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Author Topic:   old boat, new engine some questions!
akcabedo posted 06-03-2003 05:26 PM ET (US)   Profile for akcabedo   Send Email to akcabedo  
A year after my old engine gave up the ghost, I have finally got myself a new Merc 150 efi. The boat is an outrage II (Hull No. BWC8036?C292). The boat goes well, gives me 20 kts at 3,300 revs and 33kts at 5,600 revs with just me and 1/2 a fuel tank. Problem is the engine is rated to rev at between 5,000 and 5,600 and as it is now the revs creep up to about 5,800. I presume it shouldn't be doing this! The propeller number is 48 16440 A45 16P , I think it's a 16" dia, don't know what pitch.
I need to get the revs down, and I would like to know how I can reduce fuel consumption (fuel here in Gibraltar is very expensive!) Are there an ideal set of conditions one can aspire to!!?( Prop, revs, trim etc?) Also, once I'm on the plane, the engine having been trimmeed right in, a huge plume of water shoots up on either side of the engine, and the only way to get rid of it seems to be to trim the engine almost as far out as it will safely go and still stay in the water. (I must admit this trimming thing has me a little baffled, can't quite work it out!) Regarding my fuel consumption, (I don't know if this is good or bad) roughly it seems to be around 27lts an hour, (this running the boat at various speeds etc.,
Any comments, advice etc gratefully received!
JBCornwell posted 06-03-2003 05:48 PM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
Howdy, AKCabedo.

Sounds like you have more than one opportunity to improve your boat's performance.

First: Examine the relationship between the AV plate and the keel. The AV plate should be even to 1.5" above the keel and parallel with the bottom of the boat at neutral (zero) trim. Some folks would say 2" above the keel.

A wedge between transom and engine can correct trim errors. The engine can be raised to correct for too low mounting.

Once satisfied with those concerns you probably will need a 17" or 18" pitch prop to replace the 16" you are now runnning. If you have made significant changes in the engine rigging you might even find a 19" to 21" works better.

Your boat should be able to reach the low to mid 40mph range with a 150.

Sal may want to add to or argue with my suggestions. If so, use his advice.

Red sky at night. . .

Sal DiMercurio posted 06-03-2003 06:31 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
First of all, your engine is mounted to low on the transom, i'd bring it up 2 holes & see if you still get the 2 rooster tails on each side of the engine, if not, your on tract.
Second, the 16 is the pitch, no such thing as a 16" diameter for an outboard, it would hit the anti vent plate.
JB is on target when he said the 16 pitch might not be enough after you raise the engine about an inch & 1/4.
When raising the engine higher on the transom your going to gain more rpms depending how high you raise it.
My thoughts are, you may need to go to a 14.25 x 19 or even a 21 pitch as JB recommends, but we don't know just yet until you raise the engine & try a 14.25 x 19 & see just how many rpms the engine is twisting the prop.
I think it will twist a 19 [ after raising the engine ] to about 5,600 - 5,700 & if thats the case, your dialed in, if she wants to run at 6,000 with the 19 p, then you must change the prop to a 14.25 x 21.
We can't tell you exactly which prop is going to be right until you raise it & try the 19p.
Let us know & we will correct it if it's still off.
Check your rpms with the engine trimmed out & a normal load as you would carry on any given day, not empty on fuel & alone in the boat, unless thats how you run 90% of the time.
JB gave you the correct answers, i'm just backing up what he said & trying to explain it to you in laymans language in case you didn't understand.
akcabedo posted 06-04-2003 03:37 AM ET (US)     Profile for akcabedo  Send Email to akcabedo     
thanks guys, your comments make sense, I seem to remember that my last engine was a little higher, (the bracket didn'y quite touch the top of the transom) and I also seem to get a load of porpoising or the rooster tails! I will make the adjustments and get back to you. Thanks again
lhg posted 06-04-2003 12:35 PM ET (US)     Profile for lhg    
Since the 19' Outrage II is quite heavy for it's size, the engine may not take as much pitch as you think. You indicate a 16" pitch prop. Mercury makes very few props for that engine in even pitch sizes. The 4 blade aluminum is the only one I know of, and I would not recommend it.

My experience with that boat is the transom is quite short on it, and the engine should be in the 3rd (middle) set of holes. For this height you will need a Mercury performance line prop, and I would recommend the 17" 4 bladed "Offshore". These hold like glue, and are for heavier loads relative to engine HP. The Mirage model would be an alternative, but they are more for top speed. Both have the large blade areas to carry the load. My Mercury charts show that you should achieve close to 46 MPH with a 17" prop like these. The 19" versions indicate 51 MPH, and I'm not sure the boat will go that fast with 150HP.

You might want to check for prop information and pitch selection.

akcabedo posted 06-04-2003 05:28 PM ET (US)     Profile for akcabedo  Send Email to akcabedo     
I've got some pals to help me lift the engine on Monday, I've managed to get a 14.25 x 19 prop, I'm not sure the dealer here will have a 17" 4 bladed "offshore", I'll ask, meanwhile I'll try upping the engine and adding the 14.25 x 19. Will post the results soon.
Thanks Adrian
Can't open prop selector on the mercurymarine site with my mac!
gvisko posted 06-04-2003 07:01 PM ET (US)     Profile for gvisko  Send Email to gvisko     
My 83 18,6 outrage with new johnson 150
2 stroke runing a 14.25x19 stainless
prop runs wot 5200 rpms and tops out
at 45 gps .Do you guys think this is about
right or should I reprop to get rpms up ?
the boat also has a t-top

thanks george visko

Sal DiMercurio posted 06-04-2003 07:11 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
George, if you drop to a 17 pitch your engine will run 5,600 rpms & i'm sure it would be happier.
It's possible to even gain 1 - 2 mph because of the rpms.
If your engine is mounted all the way down, you can come up a couple holes & that would give you 5,400 rpms, maybe a few more.
I kinda feel the 19 pitch is a bit much for that setup, but as long as she can get to 5,500 rpms, thats what matters.
gvisko posted 06-04-2003 07:29 PM ET (US)     Profile for gvisko  Send Email to gvisko     
Thanks sal I thought that was the way to
go but was not sure. I will keep you posted.

many thanks george v

akcabedo posted 06-09-2003 03:44 PM ET (US)     Profile for akcabedo  Send Email to akcabedo     
OK, I just got back from making the suggested changes and here's the thing!:

engine mounted on top hole, (ie as low as it would go).
Huge rooster tale at lower speeds.
Horrible porpoising.
Terrible ride in general.
Max revs. 5,800 (over the max by 200)
Max speed 33mph

After raising the engine by about 1 1/4" (2 holes) and changing the prop from a 16" to a 19" as suggested:

Max revs 5,400
Max speed 35mph ( a gain of 2 mph)
no rooster tale at all
No porpoising at all
better ride (I think!) I'm just so happy about everything else!

The trim gauge is now pretty useless. (can this be calibrated?) I am amazed at what a difference 11/4" makes!!! You guys are something else, the dealer was not convinced by my having come to the forum to get my info, but boy I'm glad I did. It's like a different boat, now I can really enjoy it. Thanks again guys, you made my day.
PS anyone of you ever come this way gets a few beers from me!!!!

lhg posted 06-09-2003 05:44 PM ET (US)     Profile for lhg    
Glad to hear the boat is running better, but your speed of 35 mph is too low for that engine/prop combination. You should be running upper 40's. How are you measuring speed. You may be going faster than you think.
Sal DiMercurio posted 06-09-2003 06:00 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
Ihg is right, that boat should easily run in the mid to upper 40s with a 150.
Which prop did you put on ?
If it were me, i'd put the same prop with 1 inch less pitch & allow that engine to get to 5,600 rpms.
Was the water smooth or 1' chop ?
I have the feeling your gps or speedo is off.
35 mph is just not acceptable on that rig with that engine.
I'v been trying to get Keiths boat to hit 50 & he's been telling me 32 & 36 & 38 mph.
Told him to get a 13.25 x 17 to get those rpms up, launched this morn & brought my boat to clock him, after a nice run I stopped & had him pull over, asked him what rpms he's turning & what speed?
His answer was 6,000 rpms trimmed all the way out & 38 mph.
I smiled & said, my hunch was right, your gps is waaaaaay off, your bouncing between 49 & 50 mph.
I'v got the feeling the same problem is with your rig.
akcabedo posted 06-09-2003 06:00 PM ET (US)     Profile for akcabedo  Send Email to akcabedo     
I'm using a Garmin e-trex GPS thing, have to admit though, there were four heavy guys on board when we did the test run, also I have to keep trying to get the trim right.
akcabedo posted 06-09-2003 06:12 PM ET (US)     Profile for akcabedo  Send Email to akcabedo     
Sal, you could well be right, it feels pretty fast. The propellor is a 14.25 x 19. Over the next few days I will try and also use the speedo from my fishfinder and compare that to the gps, though that is only in knots(are the two similar?) I will let you know when I've done a little more comparison.
acseatsri posted 06-09-2003 06:45 PM ET (US)     Profile for acseatsri  Send Email to acseatsri     
Not sure about your's, but my GPS reads in knots. If so, multiply your reading by 1.15 to convert to MPH. Another thing I notice is that bottom paint knocks a considerable amount of speed off the top end. I'm considering applying a couple more coats on mine and then sanding it with 400 grit or so to smooth it out.
Sal DiMercurio posted 06-09-2003 11:38 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
Adrian, an easy way to be close, but not exact [ you will be moving a hair faster then what i'm saying ], instead of multiplying by 1.15 just figure for every 10 kts, your going a hair over 11 mph such as 10 kts = 11 mph, 20 kts = 22 mph, 30 kts = 33 mph, 40 kts = 44 mph 50 kts = 55 mph [ probably closer to 56 mph ].
Knotts is faster, so it reads slower on the speedo then mph.
acseatsri posted 06-10-2003 12:53 AM ET (US)     Profile for acseatsri  Send Email to acseatsri     
A lot of the thread here has been devoted to obtaining max speed. Sometimes setting up the boat more for power is the way to go, especially if you spend a significant amount of time in the big pond climbing over larger waves. Easy way to do this is to drop down 2" in pitch, just being careful not to over-rev.
akcabedo posted 06-10-2003 05:37 PM ET (US)     Profile for akcabedo  Send Email to akcabedo     
ok I've been out again and the speed still seems to be around the 35mph max ( my gps has statute miles, nautical or metric). Having said that, it's plenty fast for me, not really much of a speed freak, I'm more interested in economy. my ability to trim the engine seems more restricted than before, not so much movement.I'm not sure now whether I;ve really cure the porpoising as it still seems to do it a little, mind you there's been a constant swell lately so I can't really tell yet. The revs a still at about 5,300, some 300 lower than max. Should I be happy with these figures?
lhg posted 06-11-2003 05:34 PM ET (US)     Profile for lhg    
In what kind of shape is the hull bottom? Painted? Tee Top? Both are speed killers.

It seems inconceivable to me that the brand new 150 EFI will not generate more speed. Unless the engine is malfunctioning?

A friend has same boat with 1992 150 Yamaha on it, engine all the way down, and he gets 42 MPH. There is no way that a brand new 150 Mercury EFI won't walk away from a 10 year old 150 carbed Yamaha.

lhg posted 06-11-2003 05:43 PM ET (US)     Profile for lhg    
Further to this issue, if engine is fine, and GPS is correct, the prop is bad, maybe a spun hub or slipping hub, maybe pitched incorrectly. This sounds like the REAL problem. I think you said the prop had been repaired. Try out a brand new propeller, 17" pitch. I'm betting on bad prop. This issue has come up here before, and it's a very deceptive problem to figure out.
akcabedo posted 06-13-2003 03:49 PM ET (US)     Profile for akcabedo  Send Email to akcabedo     
My gps was obviously a bit off, I borrowed a friends and having finally found a small patch of flat water I topped out at 43.4mph at 5,300 rpm. (I think I'm still getting a bit of porpoising though, or maybe I haven't got the hang of the trimming yet!)
Thanks everyone for great advice and comments (something definitely lacking in this area!)
lhg posted 06-13-2003 05:47 PM ET (US)     Profile for lhg    
OK, now we're talking. That sounds more like it.

I'm beginning to think that not all GPS receivers are created equal. As I mentioned in another post, I read somewhere in a boating mag that for accurate speed, you really need DGPS. Guess this proves it out.

Perry posted 06-13-2003 09:26 PM ET (US)     Profile for Perry  Send Email to Perry     
I have the same Garmin e-trex. It is very accurate. According to 3 different radar displays on the highway and my 2003 Volvo's speedometer, it is spot on.
akcabedo posted 06-22-2003 12:20 PM ET (US)     Profile for akcabedo  Send Email to akcabedo     
Back again! I've been using the boat for a while now, and whilst I'm more than happy with my top speed I have a few worries about the general performance. Unfortunately I am unable to go to my local dealer/mechanic anymore as he thinks I went behind his back and that basically I (in a roundabout way) called him incompotent or at least insinuated it!
The boat has unpleasant ride in anything but absolute flat (a rarity here) it pounds and slams into even the smallest wave.
My trim capabilities I think, have been reduced by lifting the engine, the only setting that seems to get me on the plane and semi ok after that is trimmed right in as far as it will go. If I trim out the ride deteriorates. I'm not sure whether the engine should be able to trim further in.
The consumption seems very high, even for a 150, it seems to drink as much as my old 200 did.
I'm a bit peeved because I can't find anyone here who knows anything that can simply go out on the boat with me and see what problems she may have and more importanatly how to solve them!
I'm sure this boat/engine combination should give me a sweet ride and reasonable fuel consumption, just not sure how to achieve it. Any suggestions gratefully accepted!!! Thanks.
akcabedo posted 06-22-2003 03:46 PM ET (US)     Profile for akcabedo  Send Email to akcabedo     
forgot to add; the steering has also gone a little peculiar, at slow speeds (before plane) it becomes very heavy, on occasions it also feels as if it has "steps" as you turn. The steering system is a Morse Hydraulic system and I don't remember these problems being there with the old engine.
Sal DiMercurio posted 06-22-2003 06:40 PM ET (US)     Profile for Sal DiMercurio  Send Email to Sal DiMercurio     
Sounds to me like you need a lifting prop such as a Stiletto to get the hull up & out of the water.
By raising the engine, it should have stopped the porpoising & given you a softer ride.
The only time the boat should be slaming down on the water is if your trimmed all the way in, the ride gets softer as you trim out.
If your still porpoising, you should raise the engine higher to stop it.
akcabedo posted 06-23-2003 02:41 AM ET (US)     Profile for akcabedo  Send Email to akcabedo     
thanks Sal, what's a Stilleto prop?
Backlash posted 06-27-2003 09:57 AM ET (US)     Profile for Backlash  Send Email to Backlash     

The Garmin eTrex 12 channel receivers are WAAS enabled which provides accuracy down to 3 meters, while DGPS provides accuracy down to 6 meters.


Landlocked posted 06-27-2003 02:18 PM ET (US)     Profile for Landlocked  Send Email to Landlocked     
I may be off base here but are WAAS signals broadcast in Gibralter ? I thought that it was pretty much a North American correction....

As far as the porpoising - have you thought about weight distribution? Try moving a few items towards the bow and see what happens.


kingfish posted 06-27-2003 02:30 PM ET (US)     Profile for kingfish  Send Email to kingfish     

I'll check, but I think my DGPS (Garmin 181 I think, associated with a Garmin GPSMap 235) is accurate to 3 meters.


Barry posted 06-27-2003 02:30 PM ET (US)     Profile for Barry  Send Email to Barry     
I have a Garmin GPSmap 76, and while it is WAAS enabled I believe the default mode is "Battery Saver" which disables WAAS.
Landlocked posted 06-27-2003 02:30 PM ET (US)     Profile for Landlocked  Send Email to Landlocked     
According to the Garmin Website

The following is a direct cut and paste quote from the reference above... No plagerism is intended..

"Currently, WAAS satellite coverage is only available in North America. There are no ground reference stations in South America, so even though GPS users there can receive WAAS, the signal has not been corrected and thus would not improve the accuracy of their unit. For some users in the U.S., the position of the satellites over the equator makes it difficult to receive the signals when trees or mountains obstruct the view of the horizon. WAAS signal reception is ideal for open land and marine applications. WAAS provides extended coverage both inland and offshore compared to the land-based DGPS (differential GPS) system. Another benefit of WAAS is that it does not require additional receiving equipment, while DGPS does."

Backlash posted 06-28-2003 08:46 AM ET (US)     Profile for Backlash  Send Email to Backlash     
Landlocked, the intention of my original post was to point out to Larry that the eTrex GPS units with WAAS enabled are highly accurate receivers, possibly more accurate than DGPS. Of course I failed to check Adrian's profile to see that he was from Gibraltar! My mistake.

John, I got the 6 meter accuracy reference for DGPS from the West catalog. Nuff said?

Barry, you are correct, the Garmin hand helds default to the battery saver mode which disables WAAS.


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