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Author Topic:   16-footer, Suzuki DF70

NJCoastFlyFish posted 06-01-2007 12:32 AM ET (US)
Dealer [installed the] wrong [propeller on my] 1966 16-foot Boston Whaler boat with a new Suzuki DF70. I ordered the stainless propeller with the engine and [the dealer] tried out an 18-inch pitch propeller. [I] was told it didn't turn enough RPM. I thought this was the perfect prop? [The dealer] told me they have to order the 16-inch pitch propeller which would go better with the boat. For the meantime they gave me a 15-inch pitch aluminum propeller. The 15-inch pitch aluminum propeller obviously turns way more than the maximum RPM that this engine should deliver.
I'm thinking a 16-inch stainless steel propeller isn't going to help all that much over the 15-inch aluminum propeller. I'm confused on how they are going about [selecting the propeller]. I think I'm going to get [forced against my will] into buying a stainless prop that I'm going to end up replacing. I'm a little confused on how to go about solving this problem
Could engine height be playing a factor [in selecting the proper propeller]?
With the 15-inch aluminum propeller [the performace is]:
2000-RPM = 5-MPH
4000-RPM = 17-MPH or 20-MPH, depending on sea conditions.
Speed measured by GPS. I should be fetching better numbers than that.
rtk posted 06-01-2007 08:04 AM ET (US)
Congrats on the new engine.
Try to find out the RPM at wide-open throttle with the 18-inch pitch propeller. You can use that as a benchmark.
The proper propeller will allow the boat to run in the proper rpm range when running at wide open throttle.
Rich
jimh posted 06-01-2007 09:01 AM ET (US)
Give the following information:
--engine gear ratio
--engine maximum speed in RPM
--engine speed observed at wide-open throttle with each propeller tested
Tom W Clark posted 06-01-2007 09:44 AM ET (US)
There are a lot of propellers with 18 inches of pitch that will fit a Suzuki DF70. Would you care to tell us exactly WHICH prop it was? It just might be a relevant piece of information.
Tohsgib posted 06-01-2007 11:12 AM ET (US)
Well I assume he means a Suzuki prop. Yes the 13x18" is perfect, 17" is good for heavy loads. 15-16 just too darn small. My heavier 17 Newtauk would fetch about 5600WOT and redline is 5800. Tell your dealer you want to try the 18 because the 15 is too small. When he gives it to you, try it and probably keep it. Don't be a wuss ;)
bamatenn posted 06-01-2007 08:27 PM ET (US)
Go with the Suzuki 13 x 18 SST prop and raise the engine 3" above the AV plate. You'll be happy.
Ken
Tom W Clark posted 06-02-2007 10:01 AM ET (US)
I do not assume much. To assume things mean you will make mistakes when the assumptions are wrong. The old adage applies: Garbage in, garbage out.
NJCoastFlyFish,
If your dealer cannot prop your boat correctly, I can. Do not limit yourself to thinking your dealer is the only place to buy a prop.
I agree a trial with speed and rpm data is the best way to deduce if a propeller is suitable or not.
Yes, engine height will affect the boat's performance.
NJCoastFlyFish posted 06-02-2007 04:45 PM ET (US)
Ok- After a heavy weekend of boating here is what I found out-
Stainless 13 1/4 X 18in Suzuki prop went 4800rpm max
Aluminum 13 1/4 X 17in Suzuki prop went 5500rpm max
Aluminum 13 1/2 X 15in Suzuki prop went 6000 + max
I have the 17in pitch prop on there now and waiting for the 16in stainless suzuki prop in the mail, the dealer was kind enough to let me test all of these props out, and I think the 16in will be the best.
The 17in pitch prop does 22/23 mph at 4000 with a slight chop in sea conditions.
Bottom line is I don't think the engine is mounted right. I think for the mounting it is at now the 16in stainless suzuki prop will be a good all around choice, it is 13 1/4 X 16in and should give me the upper range of the engines operating rpm with just me on board and with a slight load it should go down a little. I won't be able to test it until some time next week.
I am not getting anywhere near the 39mph others have gotten with this same engine, or the gas mileage, so something has to change which will probably take place at the beginning of next season because I have no trailer for this boat and it is moored-
Other than that I am extremelly pleased with this engine and set up. I love the way it hums over my old 2-stroke yamaha v6 and even though i'm not getting 10mpg it sipped around 6 gallons for a 25mile or so trip with two people on boats and choppy sea conditions which I hope will get better once the engine breaks in. In hindsight this is better than the 18gallons it would have took me on the old grady.
NJCoastFlyFish posted 06-02-2007 04:50 PM ET (US)
The maximum engine operating speed in rpm for this engine is 5800/5900.
Unfortunately I did not get the gps speed numbers when maxed out- Honestly it was "fast enough" for me considering the sea conditions yesterday I couldn't keep it up that long, just long enough to see it get up in rpm then lay back. Also, it probably isn't good for the break in to beat the engine up but once I get some good days this week I will come back with better data.
NJCoastFlyFish posted 06-07-2007 10:38 AM ET (US)
Since the beginning of this post the engine has actually seemed to loosen up a lot, I can't explain it but it is running a lot better now.
Yesterday at 4000 rpm with a 17in alum prop I got a nice cruise at 25mph with two people on board and moderate choppy conditions.
The fuel usage for this engine has also imporved averaging between 3-4 gallons for 25 mile trips.
These trips are usually 10 mile runs north and 10 mile runs south with about 5 miles of running while reseting the drift in between so I can't say the wind, current, or water conditions affected the improved gas mileage because it is an equal run both ways.
Love the engine-
Tohsgib posted 06-07-2007 01:15 PM ET (US)
That is why it is called the break-in period. You get even better performance in another 20+ hours.
NedsPoint posted 06-10-2007 07:57 AM ET (US)
Mine tops out at 5600. The speed is disappointing at 33mph tops. Great gas mileage and reliability, poor performance and weight load....guess its a trade.
Has anybody seen [a problem] with trimming the engine when operating at high speeds? I can't trim mine more than an inch or so or it sounds the overheat or lack of cooling alarm. Had it back to the dealer three times, he said it is operating normally. Makes the boat plow a bit.
NJCoastFlyFish posted 06-10-2007 08:42 PM ET (US)
That is interesting about the engine cooling alarm going off. I have had mine trimmed up until the rpm's start fluctuating on my 16fter and no cooling alarm, she still piss's water. Maybe your engine is mounted too high ?
If the boat is plowing trimming the engine up will help but it seems you can't do that, ever think about a bracket?
NedsPoint posted 06-11-2007 04:29 AM ET (US)
Engine is mounted all the way down on a 17 ft Newport. Believe me, we have explored all possibilities, and I have learned to live with it. Not the optimal power plant in my mind.
Tohsgib posted 06-11-2007 10:27 AM ET (US)
Nedspoint I have said this many times. Without being able to trim it, she is not going to give you the other 4+mph. I would take it to a different dealer being you are the ONLY one with that problem.
NJCoastFlyFish posted 06-11-2007 11:54 AM ET (US)
Ned- Not every dealer is going to know the best way of going about powering all boats. Have you ever considered a jackplate/setback bracket? That might help get the engine into cleaner water and help on performance.
I just called my dealer about adding a bracket to my boat and they are telling me it will offer no advantages to my set up but they also propped me wrong from the get go so I don't know what to beleive.
The members of this site that preach for the suzuki df70 all have set back brackets, swinging 18/19in pitch props and getting close to 40mph with this engine. When I first got my engine swinging a 15in pitch prop from the dealer I was more than dissapointed at 17mph at 4000rpm. Now i'm up to 17 inches and 23/24mph at 4000 but still no where near the 40mph top end and 10mpg set-up I thought I could acheive. I think engine height is the key to getting the suzuki into a speed range that is more desirable for whaler owners but my dealer doesn't think so and doesn't want to instal the bracket.
I may just run it how it is and wait until the boat is out for the winter to start changing things around.
Tohsgib posted 06-11-2007 12:21 PM ET (US)
Yo also said you transom was raised up a couple inches so I doubt a setback wll do much more for you. What are running WOT full tilt boogie(mph & rpm)? Again with most light load runners the 18" Suzki prop is great. Some here run the 17" OMC SS prop which did not work that well for me. Without jackplate and right setup you should see 37 or so. Many with 90 e-tecs are not getting 40mph.
NedsPoint posted 06-11-2007 08:00 PM ET (US)
I've discussed this ad-nauseum with members here a year ago. My Suzuki dealer is the largest dealer in New England. I am relatively disappointed in this over-weight engine, but as I said before, it seems to be reliable and fuel efficient.
I would love a v-4 Johnson 90 2-stk. Thats what I took off (it was a few years old and questionable reliability), it was a lot lighter and cranked!!!
NJCoastFlyFish posted 06-11-2007 09:13 PM ET (US)
Tohs- Yeah the 18in would probably be good if I was the only one to ever use the boat, even the 17in had trouble getting up to over 5200 with three people so I think the 16in stainless will be a good all around but I am definitely going to buy an 18in-
Neds- Remember at the end of the day you need to get from point A to B, some engines can't even do that and the suzuki will do it and on little gas, kind of like paying someone less to do the same job, it's a great deal!
Tohsgib posted 06-12-2007 11:34 AM ET (US)
If you are only getting that RPM with a 17, forget the 18. Did they change the gear ratio?
NJCoastFlyFish posted 06-30-2007 08:21 PM ET (US)
Here is a quick follow up-
Finally tried out the 16in stainless and it is turning tops 5500 rpm with one person which is fine for now. The stainless prop also stopped some engine vibration which is nice.
Weird thing is the 16in stainless is turning LESS rpm than the 17in aluminum ? What gives, i'm beginning to think the dealer actually gave me the 18in stainless back?!?!
Whatever prop this is i'm satisified, 5500rpm @ 35mph is plenty enough for me-
skiff posted 07-03-2007 07:41 AM ET (US)
I run the same motor on an Avon RIB 5 meter and we have a 13 x 19 Piranha (plastic) prop on it and get 5500 and about 35mph. I've got to believe they've mounted it correctly but check.... when the motor is trimmed all the way in/down, the cavitation plate should be even or within a half inch of the very lowest/bottom of your hull. I think this is standard practice for almost every motor or hull. Lower than this and you're draggin, higher than this and you cavitate when turning. Just a thought....
Tom W Clark posted 07-03-2007 09:06 AM ET (US)
"...and you cavitate when turning."
VENTILATE, not cavitate. Why is it more folks than not insist on confusing these two phenomena?
Stainless steel propellers are now universally cupped and cupped more that aluminum propellers. Cupping increases the effective pitch.
It may also be the blade design is not the same between the two propellers with the stainless steel prop having greater blade area regardless is diameter.
NJCoastFlyFish posted 07-03-2007 10:29 PM ET (US)
Whatever the differences are between the two propellers something is WRONG! I took the boat out today with four people on board, with the heavy load I could NOT stay at 4000rpm and not get a overheat alarm to come on every 10 minutes. I don't know what gives, maybe because I am running a propellor with two much pitch and too big a load? I ended up running it at 3500 rpm and that did not set off any overheat alarms but running 3500 and 15mph for an hour was painful with four people on board, boat is going to get schedualed to go back and have them figure this out. Give me SIX!!!
How hard is it for a dealer to prop a boat right? They propped me wrong from day one with a 15inch aluminum that turned well above 6000, then they gave me a 17in aluminum that was good but couldn't hit RPM with four people. Then they give me this "16in pitch" stainless prop that turns less rpm than the 17in aluminum! I swear this "16in " prop must really be an 18in, they must have forgot what I needed-
roloaddict posted 07-04-2007 12:43 AM ET (US)
NJCoastFlyfish,
Perhaps you have a fuel delivery issue. Low power under load, good cooling water, high temp alarm (due to a lean condition?).
I would check hose conections, fuel filter, blockage in the pickup, etc. Is the primer bulb sucked flat at wide open throttle?
Are you using a 3/8" fuel hose?
Is your battery healthy w/ a good charge?
Your not dragging the trailer are you? Just kidding.

New motor, big bucks, not running right, frustrating.
Sometimes when nothing makes sense, you have to check your assumptions. Are we assuming that the engine is in fact running right?
It has been my impression that propping an older whaler with a new 4S is not always an easy setup for the "average" dealer. I have watched Tom Clark help a number of folks get set up over the last few years.
Good luck, step back and look it over.
Regards,
John
roloaddict posted 07-04-2007 12:49 AM ET (US)
And you could look at the post about the flat primer bulb too. :)
NJCoastFlyFish posted 07-04-2007 09:04 AM ET (US)
Rolo- Thanks for the suggestions. I had the fuel primer bulb go flat when I forgot to open the vent to the gas tank, the engine did conk out but no alarms went off. There is definitely something causing the engine to overheat causing it to cut off to low rpm. All it takes is about 30 seconds before the engine is cool and I can run again. Maybe it was something as simple as sucking in weeds?
RWM posted 07-04-2007 10:02 PM ET (US)
Check out this thread on how I propped my Montauk with the same engine. P.S. I'm right across the Bay if you want to check it out..Bob M.
http://continuouswave.com/ubb/Forum4/HTML/000503.html
Tohsgib posted 07-05-2007 11:23 AM ET (US)
Yes weeds are bad on the bay and will overheat you quickly. You also should NOT prop a boat to run max rpm with 4 people. Prop the boat with just you and WOT full tilt.
SpeedBump posted 07-05-2007 09:00 PM ET (US)
NJ- you are all over the place with your prop discussion. Are all these props mentioned the same diameter just a different pitch and are they all the same blade type?
Props are marked with size on the collar of the hub where the prop ear is attached or under the thrust washer and prop nut. if on the collar you can read the size while mounted on the lower unit. if under the thrust washer and prop nut you may have to remove the prop to see the size.
I run a 70 Nissan 2 stroke on my Nauset 16'7" hull. Same hull as yours I believe, you have a tad more engine weight and a bit lower hp in the lower end of your engine power curve. I run a 13 1/4 diameter X 17 pitch vortex prop. A big improvement over the 13 1/4" X 17" prop that came with the engine. It was all in the blade design. Your optimum RPM range is 5200-5800 RPM as is my Nissan. I max out at 5600rpm turning a 17"pitch with a GPS measured 32mph top end, 34 w/ a tail wind and two persons on board, if I go to a 19" it drops to about 4300rpm. I can't properly swing a 19-pitch prop, just doesn't work. My engine is not raised, it’s mounted all the way down on transom and I like it that way.
With the current arrangement I can effectively carry 4 on board in a nasty mid day chop across the bay but I don’t run at WOT on days like this as I don’t want to beat the boat up or shake the stuffing out of the family, there is enough power to get the boat on plane quickly with the family onboard and all the assorted beach gear.
Find a good pitch aluminum prop that works well for you with one person onboard, find that sweet spot WOT that is in the RPM range recommended by the manufacturer. At season end take the prop to a good prop shop and have them add "a little cup" to it which will increase your effective pitch with out adding a larger prop. It can make a big difference in a positive way. IF it turns out to be too much the cup can be easily removed
If you are in the Barnegat bay area J&B props in Bayville do a nice job on props and are very reasonable.
As for your overheating problem if you are running in the Barnegat area eel grass is a major problem this time of year that will get caught on your lower unit and block the water intakes causing an overheat situation. but from your discussion it sounds like you have another issue at hand with the overheating.

NJCoastFlyFish posted 07-06-2007 12:18 AM ET (US)
Speedbump- All props are Suzuki factory props
Stainless 13 1/4 X 18in Suzuki prop went 4800rpm max
Aluminum 13 1/4 X 17in Suzuki prop went 5500rpm max
Stainless 13 1/4 X 16in Suzuki prop went 5500rpm max
Aluminum 13 1/2 X 15in Suzuki prop went 6000 + max
I would think the perfect prop would put me around 5700rpm at top end with just me but the 16in stainless seems to be the best prop for now.
Fastest out of the four so far has been the 16in pitch stainless going 35mph.

As for the overheat issue, I think I ran the boat in shallow water on plane for too long without noticing and might have damaged my water pump. I am going to do some testing tomorrow in known deep water to see if the overheat alarm comes on in a situation where I know I am not kicking up mud that could temporailly cause a lack of water issue thereby insuring me that this issue is indeed a damaged water pump. Thank god for idiot proof alarms on these new engines!
Tohsgib posted 07-06-2007 11:16 AM ET (US)
Barnegat bay is absolutely HORRIBLE for weeds and even a seasoned Bay rat like myself will overheat an engine there. for some reason I/O's grab less if any weeds but outboards pick them up quick. Running in muck will clog your engine temporarily but will not ruin a pump that easily. If you made it home, she is fine. They are tougher than you think and trust me I dredged most of Harvey Cedars as a kid. I would fetch 39 on a good day with my 17 and a 18" but I had a jackplate etc and my smirked hull although heavier might handle the weight better etc and yield better performance(who knows).

Tohsgib posted 07-06-2007 11:19 AM ET (US)
Ps...been some confusion here lately with GPS speeds. Are you running naut. or stat. miles? You should be on statute and hence why your readings are a tad slower.

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Author	Topic: 16-footer, Suzuki DF70
NJCoastFlyFish	posted 06-01-2007 12:32 AM ET (US) Dealer [installed the] wrong [propeller on my] 1966 16-foot Boston Whaler boat with a new Suzuki DF70. I ordered the stainless propeller with the engine and [the dealer] tried out an 18-inch pitch propeller. [I] was told it didn't turn enough RPM. I thought this was the perfect prop? [The dealer] told me they have to order the 16-inch pitch propeller which would go better with the boat. For the meantime they gave me a 15-inch pitch aluminum propeller. The 15-inch pitch aluminum propeller obviously turns way more than the maximum RPM that this engine should deliver. I'm thinking a 16-inch stainless steel propeller isn't going to help all that much over the 15-inch aluminum propeller. I'm confused on how they are going about [selecting the propeller]. I think I'm going to get [forced against my will] into buying a stainless prop that I'm going to end up replacing. I'm a little confused on how to go about solving this problem Could engine height be playing a factor [in selecting the proper propeller]? With the 15-inch aluminum propeller [the performace is]: 2000-RPM = 5-MPH 4000-RPM = 17-MPH or 20-MPH, depending on sea conditions. Speed measured by GPS. I should be fetching better numbers than that.
rtk	posted 06-01-2007 08:04 AM ET (US) Congrats on the new engine. Try to find out the RPM at wide-open throttle with the 18-inch pitch propeller. You can use that as a benchmark. The proper propeller will allow the boat to run in the proper rpm range when running at wide open throttle. Rich
jimh	posted 06-01-2007 09:01 AM ET (US) Give the following information: --engine gear ratio --engine maximum speed in RPM --engine speed observed at wide-open throttle with each propeller tested
Tom W Clark	posted 06-01-2007 09:44 AM ET (US) There are a lot of propellers with 18 inches of pitch that will fit a Suzuki DF70. Would you care to tell us exactly WHICH prop it was? It just might be a relevant piece of information.
Tohsgib	posted 06-01-2007 11:12 AM ET (US) Well I assume he means a Suzuki prop. Yes the 13x18" is perfect, 17" is good for heavy loads. 15-16 just too darn small. My heavier 17 Newtauk would fetch about 5600WOT and redline is 5800. Tell your dealer you want to try the 18 because the 15 is too small. When he gives it to you, try it and probably keep it. Don't be a wuss ;)
bamatenn	posted 06-01-2007 08:27 PM ET (US) Go with the Suzuki 13 x 18 SST prop and raise the engine 3" above the AV plate. You'll be happy. Ken
Tom W Clark	posted 06-02-2007 10:01 AM ET (US) I do not assume much. To assume things mean you will make mistakes when the assumptions are wrong. The old adage applies: Garbage in, garbage out. NJCoastFlyFish, If your dealer cannot prop your boat correctly, I can. Do not limit yourself to thinking your dealer is the only place to buy a prop. I agree a trial with speed and rpm data is the best way to deduce if a propeller is suitable or not. Yes, engine height will affect the boat's performance.
NJCoastFlyFish	posted 06-02-2007 04:45 PM ET (US) Ok- After a heavy weekend of boating here is what I found out- Stainless 13 1/4 X 18in Suzuki prop went 4800rpm max Aluminum 13 1/4 X 17in Suzuki prop went 5500rpm max Aluminum 13 1/2 X 15in Suzuki prop went 6000 + max I have the 17in pitch prop on there now and waiting for the 16in stainless suzuki prop in the mail, the dealer was kind enough to let me test all of these props out, and I think the 16in will be the best. The 17in pitch prop does 22/23 mph at 4000 with a slight chop in sea conditions. Bottom line is I don't think the engine is mounted right. I think for the mounting it is at now the 16in stainless suzuki prop will be a good all around choice, it is 13 1/4 X 16in and should give me the upper range of the engines operating rpm with just me on board and with a slight load it should go down a little. I won't be able to test it until some time next week. I am not getting anywhere near the 39mph others have gotten with this same engine, or the gas mileage, so something has to change which will probably take place at the beginning of next season because I have no trailer for this boat and it is moored- Other than that I am extremelly pleased with this engine and set up. I love the way it hums over my old 2-stroke yamaha v6 and even though i'm not getting 10mpg it sipped around 6 gallons for a 25mile or so trip with two people on boats and choppy sea conditions which I hope will get better once the engine breaks in. In hindsight this is better than the 18gallons it would have took me on the old grady.
NJCoastFlyFish	posted 06-02-2007 04:50 PM ET (US) The maximum engine operating speed in rpm for this engine is 5800/5900. Unfortunately I did not get the gps speed numbers when maxed out- Honestly it was "fast enough" for me considering the sea conditions yesterday I couldn't keep it up that long, just long enough to see it get up in rpm then lay back. Also, it probably isn't good for the break in to beat the engine up but once I get some good days this week I will come back with better data.
NJCoastFlyFish	posted 06-07-2007 10:38 AM ET (US) Since the beginning of this post the engine has actually seemed to loosen up a lot, I can't explain it but it is running a lot better now. Yesterday at 4000 rpm with a 17in alum prop I got a nice cruise at 25mph with two people on board and moderate choppy conditions. The fuel usage for this engine has also imporved averaging between 3-4 gallons for 25 mile trips. These trips are usually 10 mile runs north and 10 mile runs south with about 5 miles of running while reseting the drift in between so I can't say the wind, current, or water conditions affected the improved gas mileage because it is an equal run both ways. Love the engine-
Tohsgib	posted 06-07-2007 01:15 PM ET (US) That is why it is called the break-in period. You get even better performance in another 20+ hours.
NedsPoint	posted 06-10-2007 07:57 AM ET (US) Mine tops out at 5600. The speed is disappointing at 33mph tops. Great gas mileage and reliability, poor performance and weight load....guess its a trade. Has anybody seen [a problem] with trimming the engine when operating at high speeds? I can't trim mine more than an inch or so or it sounds the overheat or lack of cooling alarm. Had it back to the dealer three times, he said it is operating normally. Makes the boat plow a bit.
NJCoastFlyFish	posted 06-10-2007 08:42 PM ET (US) That is interesting about the engine cooling alarm going off. I have had mine trimmed up until the rpm's start fluctuating on my 16fter and no cooling alarm, she still piss's water. Maybe your engine is mounted too high ? If the boat is plowing trimming the engine up will help but it seems you can't do that, ever think about a bracket?
NedsPoint	posted 06-11-2007 04:29 AM ET (US) Engine is mounted all the way down on a 17 ft Newport. Believe me, we have explored all possibilities, and I have learned to live with it. Not the optimal power plant in my mind.
Tohsgib	posted 06-11-2007 10:27 AM ET (US) Nedspoint I have said this many times. Without being able to trim it, she is not going to give you the other 4+mph. I would take it to a different dealer being you are the ONLY one with that problem.
NJCoastFlyFish	posted 06-11-2007 11:54 AM ET (US) Ned- Not every dealer is going to know the best way of going about powering all boats. Have you ever considered a jackplate/setback bracket? That might help get the engine into cleaner water and help on performance. I just called my dealer about adding a bracket to my boat and they are telling me it will offer no advantages to my set up but they also propped me wrong from the get go so I don't know what to beleive. The members of this site that preach for the suzuki df70 all have set back brackets, swinging 18/19in pitch props and getting close to 40mph with this engine. When I first got my engine swinging a 15in pitch prop from the dealer I was more than dissapointed at 17mph at 4000rpm. Now i'm up to 17 inches and 23/24mph at 4000 but still no where near the 40mph top end and 10mpg set-up I thought I could acheive. I think engine height is the key to getting the suzuki into a speed range that is more desirable for whaler owners but my dealer doesn't think so and doesn't want to instal the bracket. I may just run it how it is and wait until the boat is out for the winter to start changing things around.
Tohsgib	posted 06-11-2007 12:21 PM ET (US) Yo also said you transom was raised up a couple inches so I doubt a setback wll do much more for you. What are running WOT full tilt boogie(mph & rpm)? Again with most light load runners the 18" Suzki prop is great. Some here run the 17" OMC SS prop which did not work that well for me. Without jackplate and right setup you should see 37 or so. Many with 90 e-tecs are not getting 40mph.
NedsPoint	posted 06-11-2007 08:00 PM ET (US) I've discussed this ad-nauseum with members here a year ago. My Suzuki dealer is the largest dealer in New England. I am relatively disappointed in this over-weight engine, but as I said before, it seems to be reliable and fuel efficient. I would love a v-4 Johnson 90 2-stk. Thats what I took off (it was a few years old and questionable reliability), it was a lot lighter and cranked!!!
NJCoastFlyFish	posted 06-11-2007 09:13 PM ET (US) Tohs- Yeah the 18in would probably be good if I was the only one to ever use the boat, even the 17in had trouble getting up to over 5200 with three people so I think the 16in stainless will be a good all around but I am definitely going to buy an 18in- Neds- Remember at the end of the day you need to get from point A to B, some engines can't even do that and the suzuki will do it and on little gas, kind of like paying someone less to do the same job, it's a great deal!
Tohsgib	posted 06-12-2007 11:34 AM ET (US) If you are only getting that RPM with a 17, forget the 18. Did they change the gear ratio?
NJCoastFlyFish	posted 06-30-2007 08:21 PM ET (US) Here is a quick follow up- Finally tried out the 16in stainless and it is turning tops 5500 rpm with one person which is fine for now. The stainless prop also stopped some engine vibration which is nice. Weird thing is the 16in stainless is turning LESS rpm than the 17in aluminum ? What gives, i'm beginning to think the dealer actually gave me the 18in stainless back?!?! Whatever prop this is i'm satisified, 5500rpm @ 35mph is plenty enough for me-
skiff	posted 07-03-2007 07:41 AM ET (US) I run the same motor on an Avon RIB 5 meter and we have a 13 x 19 Piranha (plastic) prop on it and get 5500 and about 35mph. I've got to believe they've mounted it correctly but check.... when the motor is trimmed all the way in/down, the cavitation plate should be even or within a half inch of the very lowest/bottom of your hull. I think this is standard practice for almost every motor or hull. Lower than this and you're draggin, higher than this and you cavitate when turning. Just a thought....
Tom W Clark	posted 07-03-2007 09:06 AM ET (US) "...and you cavitate when turning." VENTILATE, not cavitate. Why is it more folks than not insist on confusing these two phenomena? Stainless steel propellers are now universally cupped and cupped more that aluminum propellers. Cupping increases the effective pitch. It may also be the blade design is not the same between the two propellers with the stainless steel prop having greater blade area regardless is diameter.
NJCoastFlyFish	posted 07-03-2007 10:29 PM ET (US) Whatever the differences are between the two propellers something is WRONG! I took the boat out today with four people on board, with the heavy load I could NOT stay at 4000rpm and not get a overheat alarm to come on every 10 minutes. I don't know what gives, maybe because I am running a propellor with two much pitch and too big a load? I ended up running it at 3500 rpm and that did not set off any overheat alarms but running 3500 and 15mph for an hour was painful with four people on board, boat is going to get schedualed to go back and have them figure this out. Give me SIX!!! How hard is it for a dealer to prop a boat right? They propped me wrong from day one with a 15inch aluminum that turned well above 6000, then they gave me a 17in aluminum that was good but couldn't hit RPM with four people. Then they give me this "16in pitch" stainless prop that turns less rpm than the 17in aluminum! I swear this "16in " prop must really be an 18in, they must have forgot what I needed-
roloaddict	posted 07-04-2007 12:43 AM ET (US) NJCoastFlyfish, Perhaps you have a fuel delivery issue. Low power under load, good cooling water, high temp alarm (due to a lean condition?). I would check hose conections, fuel filter, blockage in the pickup, etc. Is the primer bulb sucked flat at wide open throttle? Are you using a 3/8" fuel hose? Is your battery healthy w/ a good charge? Your not dragging the trailer are you? Just kidding. New motor, big bucks, not running right, frustrating. Sometimes when nothing makes sense, you have to check your assumptions. Are we assuming that the engine is in fact running right? It has been my impression that propping an older whaler with a new 4S is not always an easy setup for the "average" dealer. I have watched Tom Clark help a number of folks get set up over the last few years. Good luck, step back and look it over. Regards, John
roloaddict	posted 07-04-2007 12:49 AM ET (US) And you could look at the post about the flat primer bulb too. :)
NJCoastFlyFish	posted 07-04-2007 09:04 AM ET (US) Rolo- Thanks for the suggestions. I had the fuel primer bulb go flat when I forgot to open the vent to the gas tank, the engine did conk out but no alarms went off. There is definitely something causing the engine to overheat causing it to cut off to low rpm. All it takes is about 30 seconds before the engine is cool and I can run again. Maybe it was something as simple as sucking in weeds?
RWM	posted 07-04-2007 10:02 PM ET (US) Check out this thread on how I propped my Montauk with the same engine. P.S. I'm right across the Bay if you want to check it out..Bob M. http://continuouswave.com/ubb/Forum4/HTML/000503.html
Tohsgib	posted 07-05-2007 11:23 AM ET (US) Yes weeds are bad on the bay and will overheat you quickly. You also should NOT prop a boat to run max rpm with 4 people. Prop the boat with just you and WOT full tilt.
SpeedBump	posted 07-05-2007 09:00 PM ET (US) NJ- you are all over the place with your prop discussion. Are all these props mentioned the same diameter just a different pitch and are they all the same blade type? Props are marked with size on the collar of the hub where the prop ear is attached or under the thrust washer and prop nut. if on the collar you can read the size while mounted on the lower unit. if under the thrust washer and prop nut you may have to remove the prop to see the size. I run a 70 Nissan 2 stroke on my Nauset 16'7" hull. Same hull as yours I believe, you have a tad more engine weight and a bit lower hp in the lower end of your engine power curve. I run a 13 1/4 diameter X 17 pitch vortex prop. A big improvement over the 13 1/4" X 17" prop that came with the engine. It was all in the blade design. Your optimum RPM range is 5200-5800 RPM as is my Nissan. I max out at 5600rpm turning a 17"pitch with a GPS measured 32mph top end, 34 w/ a tail wind and two persons on board, if I go to a 19" it drops to about 4300rpm. I can't properly swing a 19-pitch prop, just doesn't work. My engine is not raised, it’s mounted all the way down on transom and I like it that way. With the current arrangement I can effectively carry 4 on board in a nasty mid day chop across the bay but I don’t run at WOT on days like this as I don’t want to beat the boat up or shake the stuffing out of the family, there is enough power to get the boat on plane quickly with the family onboard and all the assorted beach gear. Find a good pitch aluminum prop that works well for you with one person onboard, find that sweet spot WOT that is in the RPM range recommended by the manufacturer. At season end take the prop to a good prop shop and have them add "a little cup" to it which will increase your effective pitch with out adding a larger prop. It can make a big difference in a positive way. IF it turns out to be too much the cup can be easily removed If you are in the Barnegat bay area J&B props in Bayville do a nice job on props and are very reasonable. As for your overheating problem if you are running in the Barnegat area eel grass is a major problem this time of year that will get caught on your lower unit and block the water intakes causing an overheat situation. but from your discussion it sounds like you have another issue at hand with the overheating.
NJCoastFlyFish	posted 07-06-2007 12:18 AM ET (US) Speedbump- All props are Suzuki factory props Stainless 13 1/4 X 18in Suzuki prop went 4800rpm max Aluminum 13 1/4 X 17in Suzuki prop went 5500rpm max Stainless 13 1/4 X 16in Suzuki prop went 5500rpm max Aluminum 13 1/2 X 15in Suzuki prop went 6000 + max I would think the perfect prop would put me around 5700rpm at top end with just me but the 16in stainless seems to be the best prop for now. Fastest out of the four so far has been the 16in pitch stainless going 35mph. As for the overheat issue, I think I ran the boat in shallow water on plane for too long without noticing and might have damaged my water pump. I am going to do some testing tomorrow in known deep water to see if the overheat alarm comes on in a situation where I know I am not kicking up mud that could temporailly cause a lack of water issue thereby insuring me that this issue is indeed a damaged water pump. Thank god for idiot proof alarms on these new engines!
Tohsgib	posted 07-06-2007 11:16 AM ET (US) Barnegat bay is absolutely HORRIBLE for weeds and even a seasoned Bay rat like myself will overheat an engine there. for some reason I/O's grab less if any weeds but outboards pick them up quick. Running in muck will clog your engine temporarily but will not ruin a pump that easily. If you made it home, she is fine. They are tougher than you think and trust me I dredged most of Harvey Cedars as a kid. I would fetch 39 on a good day with my 17 and a 18" but I had a jackplate etc and my smirked hull although heavier might handle the weight better etc and yield better performance(who knows).
Tohsgib	posted 07-06-2007 11:19 AM ET (US) Ps...been some confusion here lately with GPS speeds. Are you running naut. or stat. miles? You should be on statute and hence why your readings are a tad slower.