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Author Topic:   Four-blade Propellers

Perry posted 04-10-2006 05:57 PM ET (US)
I'm looking for a little more grip from my propeller in rough ocean conditions as well as better acceleration. My current propeller is a Powertech stainless 15.25 X 17 and it is on a Honda BF135 which is mounted two-holes up on a 190 Outrage. The gear ratio is 2.14 and the prop spins to 6,200 RPM and 45-MPH at WOT. Max RPM for this motor are 6,000.
I have very little experience with four-blade propellers and I am wondering if a four-blade stainless prop 14.25 X 17 pitch will get me to 6,000 RPM? There must be a general rule for dropping pitch when switching from a 3 blade prop to a 4 blade prop.
Any info will be appriciated.
prm1177 posted 04-10-2006 07:21 PM ET (US)
Having considered the same move this past season, the common consensus is that moving from a three- to a four-blade prop of the same pitch will lose you about 200 to 300 RPM at the top end. Since you are over-reving by 200 RPM at WOT, a four-blade 17-inch pitch would provide added grip. The lower RPM would provide added safety.
Sal DiMercurio posted 04-10-2006 07:38 PM ET (US)
Also, if you drop your engine down one set of holes you will also loose approx 200-RPM. When I run my V20 on the ocean, I run it on the second set of holes with a 19-inch pitch propeller; when I run it on the Sacramento River, I run it up on the third set of holes with a 21-inch pitch propeller that pegs the tachometer up against the rev limiter. The 17p should be fine on your rig if you drop the engine 1 set of holes, but a 4 blade will hold you on plane at lower rpms, plus give you a better bite coming out of the hole.
4 & 5 blade props are mainly for the Bass Boat boys so they can get on plane in the shortest distance because they fish very shallow water & don't want to risk hitting bottom or a stump.
Although subs use 7 blades [ and they still cavitate ] & they don't get on plane.
Sal
Tom W Clark posted 04-10-2006 08:26 PM ET (US)
Perry,
I can bore you to tears here but before we get into that let's clarify what you have reported.
I understand you have a 190 Outrage (f.k.a. Nantucket) with a Honda BF135 mounted two holes up. The gear ratio is 2.17 and the redline is 6000 RPM.
But then you say the propeller spins to 6200 RPM? I am sure you meant to sat the motor spins to 6200 RPM or 200 RPM over redline, no?
At first I misunderstood your question and assumed you have a four blade prop. But now I presume you have a three blade Powertech and are wondering if moving from a 15-1/4" x 17" three blade to a 14-1/4" x 17" four blade prop will reduce your RPMs.
To answer you rquestion I would say: It depends.
Exactly what propeller are you looking at acquiring? Not all four blade prop are created equal.
Tom W Clark posted 04-10-2006 08:33 PM ET (US)
Perry,
Running your numbers through the prop calculator I see that you slip number is an extremely low 2 percent. I suspect the Powertech has a little more than 17" of pitch.
Tom W Clark posted 04-10-2006 08:46 PM ET (US)
Perry,
Here's some comparative data from my Revenge 25 with twin Mercury 150s.
I have tried six different sets of props so far including two sets of four blade props.
The best props I have tested yet are the Mercury Mirage Plus in a 15-1/4" x 19" pitch. These are just great propellers. Very large diameter and blade area, yet fast and efficient.
I have also tried a pair of 14-5/8" x 17" Mercury Revolution 4s (heavy, large blade area props but with smaller diameters) and a pair of 14" x 19" Mercury Offshore (k.k.a. Vensura) which have small little blades and a small diameter.
The 19" Mirage Plus allows my motors to rev up to their redline of 5500 RPM. Conventional wisdom suggests that if switching to a four blade prop, I should drop down in pitch to maintain engine speed. Not so.
The 17" REV 4s spooled almost to 6000 RPM and the 19" Offshores did hit 6000 RPM. It seems the smaller diameter more than made up for the extra blade.
Perry posted 04-10-2006 09:04 PM ET (US)
Tom, sorry for the confusion. Yes, it is the motor that spins to 6200 RPM and the gear ratio is 2.14 not 2.17. My current prop is a 3 blade Powertech and yes it does achieve very low slip numbers which leads me to believe it is closer to 18 pitch than 17.
As for the type of prop I plan on getting, well, the Honda dealer who sold me the motor owes me a new stainless prop but he says it has to be from Honda Marine. Honda stamps their name on Powertech's and Solas as well as their own Honda "Turbo" models. I have to choose one of these three brands. I am leaning toward the Honda "Turbo" 4 blade because I have owned their 3 blade model and it provided good performance and low slip %. I can also choose a Powertech or Solas 4 blade prop too.
I am aware that not all 4 blade props are created equal but I was hoping to find one that gets me to 6000 RPM on the first try.
jimh posted 04-10-2006 09:04 PM ET (US)
My experience with four-blade propellers was an increase in vibration. This is somewhat counter to the conventional wisdom. I believe that it occurs because in a four-blade propeller, as the blades pass into the shadow of the gear case, there are two blades shadowed at a time. On propellers with three or five blades, only one blade at a time is shadowed.
If everything were held constant, adding a fourth blade to a three-blade design would certainly tend to make the engine speed decrease. However, it is more common that the four-blade designs have different diameters and blade shapes. When you change from a three-blade to a four-blade of the same pitch, there is an expectation of engine speed dropping, but, as Tom Clark has observed, this is not always the case. As you suggest, the four-blade propeller you are consider is smaller in diameter than the three blade.
Perry posted 04-10-2006 09:20 PM ET (US)
Tom and jimh, you both bring up a good point concerning prop diameter. The 4 blade Honda "Turbo" comes in 14.24" diameter where my current 3 blade prop is 15.25 X 17. I suppose the one inch smaller diameter may more than make up for the extra blade. If this is the case a 17 pitch 4 blade prop in 14.25 diameter may not be enough pitch and a 14.25 X 19 4 blade prop may be a better choice.
On the other hand, Powertech makes a 4 blade Offshore prop in the same 15.25 diameter as my current prop. This is the same model I have on my motor now only one has 3 blades and the other has 4. Maybe if I stick to the same brand, model, diameter and pitch but switch to 4 blades instead of three I will drop the 200 RPM and get to the 6000 RPM mark I desire.
Tom W Clark posted 04-11-2006 12:12 AM ET (US)
Perry,
Yes, I think that if there is a four blade version of what you have then yes, you will reduce your RPM and gain some thrust. But I have to say that a four blade prop with a 15-1/4" diameter is a VERY large prop. On a 135 HP motor it is even more so.
I will also tell you quite honestly, that you will not know what works until you try it out. I have been surprised several times now.
Since you are owed this prop from your dealer, he should let you trial them until you find what works best for you.
Tom W Clark posted 04-11-2006 01:12 AM ET (US)
Perry,
Crunching some numbers I think your best bet would be to select a 14-1/4" x 19" pitch prop. That seems to fit best with other performance reports I've been looking at.
I have to say that I am VERY impressed by the 45 MPH top speed of your Honda 135 on the Outrage 190. That's more or less as fast as a (much lighter) classic Outrage 18 with a classic 150 HP two stroke!
Perry posted 04-11-2006 01:34 AM ET (US)
OK Tom, I'll first try the 14-1/2 X 19 4 blade prop. I agree that 15-1/2 diameter is rather large but the BF135 uses the same gear case as the BF225 and shares the same props.
I have been quite pleased with the performance of this motor. It is essentially the same motor as the BF150 minus the VTEC. I have seen a best of 46.7 MPH (GPS) on a flat ocean with a 1/4 tank of gas and myself aboard. A two way average of 45 MPH is easily achieved.
Will the 4 blade prop provide better fuel mileage at cruise? I get over 6 MPG with the 3 blade prop @ 3500 RPM and 25 MPH as it is but more is always better.
Perry posted 04-11-2006 03:10 AM ET (US)
I meant to say I'll first try a 14-1/4 X 19 pitch prop. And I agree that a 15-1/4 diameter is rather large.
Tom W Clark posted 04-11-2006 10:58 AM ET (US)
Perry,
It is very possible that a four blade propeller will provide better fuel economy, though at your current 6 MPG, I am very jealous ;-)
Sal DiMercurio posted 04-11-2006 10:12 PM ET (US)
Perry, flat calm water is poison for Whalers.
Optimum racing water is 18" chop real close together so you can get some air under her.
Makes a difference of at least 5 mph on the top end.
On dead flat water the boat sticks like glue even trimmed out to maximum because there's no air pockets to break that suction loose.
There's absolutly no need for a 15.25 diameter prop for that rig.
When you get over 21 ft & your engine has the power to twist one, than you start looking into a bigger diameter such as a 15.25.
Sal
Perry posted 04-12-2006 12:48 AM ET (US)
Sal, I agree that 15.25" diameter is overkill for a 19 foot Whaler with 135 HP. That is one reason why I'm getting a prop in 14.25 diamerter.
I should have been more clear about what I consider a flat ocean. I was referring to 6-12 inch wind chop inside a very large bay.
bigjohn1 posted 04-12-2006 07:48 AM ET (US)
Perry,
I replaced my stock Black Max six months ago with a 4-blade Trophy Plus (170 MONTAUK/Merc 115efi). Like jimh, I have experienced a bit of vibration. It seems to come on right around 800 rpm's but is gone at around 1,100 rpm's. I will live with it for now though as the prop definitely has increased my low-end power and does indeed help me plane at a lower rpm.
Sal DiMercurio posted 04-12-2006 02:12 PM ET (US)
Bigjohn, thats strange, because a 4 blade is normally smoother than a 3 blade, & a 5 blade is smoother yet.
It is possible [ but not probable ] that both you & Jim's props were not ballanced right.
Strange...........
I would say it was the engine vibrating at idle speed, but if it didn't with the 3 blade on it, than that's not the problem.
Sal
bigjohn1 posted 04-13-2006 12:03 AM ET (US)
I hear ya load and clear Sal on 4-blades are supposed to be smoother. Since I bought my Trophy prop from a custom marine performance shop, I had them check the balance when I bought it (just to be sure). I surely thought I would see less vibration but that has not been the case - at least not in the rpm range I mentioned. Confusing to say the least!
Perry posted 04-14-2006 06:56 PM ET (US)
Tom, Sal,
I know both of you say that a 15- 1/4 diameter prop is too large for the 190 Outrage. This seems logical to mee too but when I went to Boston Whaler's performance data for the 190 Outrage, I notice that all 4 motors that are offered on this hull come from the factory with a 15- 1/4 diameter prop.
I figure Boston Whaler rigs these boats for maximum performance and efficiency. Why would they put on a 15-1/4 diameter prop if it was too large?
I know both of you have lots of experience with Whalers and props so I thought either or both of you could shed some light on this quandry.
Sal DiMercurio posted 04-14-2006 07:35 PM ET (US)
I don't even think a 15.25 diameter prop will clear the antivent plate on a 130 hp engine.
100 - 140 hp engines normally run 13.50 dia
15.25 dia is for "V"6 engines & inboard/outboards.
Unless I'm missing something here.
Don't forget Boston Whaler is selling Mercs, & your running a Honda, but there shouldn't be that much clearance between the prop blades & the antivent plate to fit a 15.25 dia prop in there with enough room to clear.
Sal
Perry posted 04-14-2006 09:10 PM ET (US)
Sal,
My motor is a 2005 BF135 The new BF135/BF150 uses the same gear case as the BF200/BF225. Thus the larger diameter props. Mine came from the dealer with a 15- 1/4 X 17 prop.
Sal DiMercurio posted 04-15-2006 11:53 AM ET (US)
I found out years ago, many dealers will put a certain prop on new engines, just because that is the prop they had in stock, or they got a deal on 6 of them for the price of 2, & now they stick them on any engine they fit on & tell the customer thats the right one.
For instance, in 1992 I bought a Johnson 150 for my "V"20 & the dealer put on a 15 x 16 OMC prop., telling me it's the right one.
Well, I know a little about props & saw that my rpms were in the right place, but my speed should have been better.
I changed that prop to a Stiletto 14.25 x 17 & picked up about 5 mph & my engine ran easier.
Later in years after they went out of business, I asked them why they put that 15 x 16 s/s OMC prop on my engine & the answer was, ..."we got a good deal on them & we had 6 of them in stock".........
Nothing is impossible.
Sal
Tom W Clark posted 04-15-2006 06:27 PM ET (US)
Perry,
I don't think a 15-1/4" diameter propeller on your boat is too large...necessarily. I do think that a FOUR blade 15-1/4" prop on your boat would be to large. It has nothing to do with clearance; as you note the prop you had fit just fine.
Let's look at some precedents. The 15-1/2" props on the Mercury equipped Outrage 190s are all Mercury Mirage Plus propellers. These are just great props (and one I would have recommended for your boat.) But they are three blade propellers, not four. I have found that the Mirage Plus's larger diameter works well to contribute stern lift which helps larger boats.
A 135 HP motor is on the bottom end of motors that will work well with the Mirage Plus. Your Honda 135 may, it may not, be able to handle it but I think it would be worth a try. Out of the six sets of props I have tried on my own boat, the Mirage Pluses have yielded the best handling and fuel economy. I have yet to try a pair of 19" Rev 4s or High Fives.
The Yamaha Saltwater Series propellers are very similar in design to the Mirage Plus. A large diameter, three blade high performance propeller used on 150 HP motors and larger. It is worth noting that Yamaha does NOT recommend their Saltwater Series propellers for their F150 four stroke. The implication being that it is really not enough motor to turn a large prop like that.
I would think that your 135 HP Honda wouldn't be much MORE powerful than the Yamaha F150, but it may have a lower gear ratio which would tend to accommodate a larger diameter prop.
At any rate this is all relative to three blade propellers and you are talking about moving to a four blade prop. I do not think that a 15-1/4" diameter four blade propeller is well advised.
As is always the case, you won't really know until you try.
Perry posted 04-16-2006 03:22 AM ET (US)
I spoke to my dealer today. I have a 14-1/4 X 19 X 4 on order. He said he will let me swap it out if I'm not pleased with it's performance. I will post the results when they become available.

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Author	Topic: Four-blade Propellers
Perry	posted 04-10-2006 05:57 PM ET (US) I'm looking for a little more grip from my propeller in rough ocean conditions as well as better acceleration. My current propeller is a Powertech stainless 15.25 X 17 and it is on a Honda BF135 which is mounted two-holes up on a 190 Outrage. The gear ratio is 2.14 and the prop spins to 6,200 RPM and 45-MPH at WOT. Max RPM for this motor are 6,000. I have very little experience with four-blade propellers and I am wondering if a four-blade stainless prop 14.25 X 17 pitch will get me to 6,000 RPM? There must be a general rule for dropping pitch when switching from a 3 blade prop to a 4 blade prop. Any info will be appriciated.
prm1177	posted 04-10-2006 07:21 PM ET (US) Having considered the same move this past season, the common consensus is that moving from a three- to a four-blade prop of the same pitch will lose you about 200 to 300 RPM at the top end. Since you are over-reving by 200 RPM at WOT, a four-blade 17-inch pitch would provide added grip. The lower RPM would provide added safety.
Sal DiMercurio	posted 04-10-2006 07:38 PM ET (US) Also, if you drop your engine down one set of holes you will also loose approx 200-RPM. When I run my V20 on the ocean, I run it on the second set of holes with a 19-inch pitch propeller; when I run it on the Sacramento River, I run it up on the third set of holes with a 21-inch pitch propeller that pegs the tachometer up against the rev limiter. The 17p should be fine on your rig if you drop the engine 1 set of holes, but a 4 blade will hold you on plane at lower rpms, plus give you a better bite coming out of the hole. 4 & 5 blade props are mainly for the Bass Boat boys so they can get on plane in the shortest distance because they fish very shallow water & don't want to risk hitting bottom or a stump. Although subs use 7 blades [ and they still cavitate ] & they don't get on plane. Sal
Tom W Clark	posted 04-10-2006 08:26 PM ET (US) Perry, I can bore you to tears here but before we get into that let's clarify what you have reported. I understand you have a 190 Outrage (f.k.a. Nantucket) with a Honda BF135 mounted two holes up. The gear ratio is 2.17 and the redline is 6000 RPM. But then you say the propeller spins to 6200 RPM? I am sure you meant to sat the motor spins to 6200 RPM or 200 RPM over redline, no? At first I misunderstood your question and assumed you have a four blade prop. But now I presume you have a three blade Powertech and are wondering if moving from a 15-1/4" x 17" three blade to a 14-1/4" x 17" four blade prop will reduce your RPMs. To answer you rquestion I would say: It depends. Exactly what propeller are you looking at acquiring? Not all four blade prop are created equal.
Tom W Clark	posted 04-10-2006 08:33 PM ET (US) Perry, Running your numbers through the prop calculator I see that you slip number is an extremely low 2 percent. I suspect the Powertech has a little more than 17" of pitch.
Tom W Clark	posted 04-10-2006 08:46 PM ET (US) Perry, Here's some comparative data from my Revenge 25 with twin Mercury 150s. I have tried six different sets of props so far including two sets of four blade props. The best props I have tested yet are the Mercury Mirage Plus in a 15-1/4" x 19" pitch. These are just great propellers. Very large diameter and blade area, yet fast and efficient. I have also tried a pair of 14-5/8" x 17" Mercury Revolution 4s (heavy, large blade area props but with smaller diameters) and a pair of 14" x 19" Mercury Offshore (k.k.a. Vensura) which have small little blades and a small diameter. The 19" Mirage Plus allows my motors to rev up to their redline of 5500 RPM. Conventional wisdom suggests that if switching to a four blade prop, I should drop down in pitch to maintain engine speed. Not so. The 17" REV 4s spooled almost to 6000 RPM and the 19" Offshores did hit 6000 RPM. It seems the smaller diameter more than made up for the extra blade.
Perry	posted 04-10-2006 09:04 PM ET (US) Tom, sorry for the confusion. Yes, it is the motor that spins to 6200 RPM and the gear ratio is 2.14 not 2.17. My current prop is a 3 blade Powertech and yes it does achieve very low slip numbers which leads me to believe it is closer to 18 pitch than 17. As for the type of prop I plan on getting, well, the Honda dealer who sold me the motor owes me a new stainless prop but he says it has to be from Honda Marine. Honda stamps their name on Powertech's and Solas as well as their own Honda "Turbo" models. I have to choose one of these three brands. I am leaning toward the Honda "Turbo" 4 blade because I have owned their 3 blade model and it provided good performance and low slip %. I can also choose a Powertech or Solas 4 blade prop too. I am aware that not all 4 blade props are created equal but I was hoping to find one that gets me to 6000 RPM on the first try.
jimh	posted 04-10-2006 09:04 PM ET (US) My experience with four-blade propellers was an increase in vibration. This is somewhat counter to the conventional wisdom. I believe that it occurs because in a four-blade propeller, as the blades pass into the shadow of the gear case, there are two blades shadowed at a time. On propellers with three or five blades, only one blade at a time is shadowed. If everything were held constant, adding a fourth blade to a three-blade design would certainly tend to make the engine speed decrease. However, it is more common that the four-blade designs have different diameters and blade shapes. When you change from a three-blade to a four-blade of the same pitch, there is an expectation of engine speed dropping, but, as Tom Clark has observed, this is not always the case. As you suggest, the four-blade propeller you are consider is smaller in diameter than the three blade.
Perry	posted 04-10-2006 09:20 PM ET (US) Tom and jimh, you both bring up a good point concerning prop diameter. The 4 blade Honda "Turbo" comes in 14.24" diameter where my current 3 blade prop is 15.25 X 17. I suppose the one inch smaller diameter may more than make up for the extra blade. If this is the case a 17 pitch 4 blade prop in 14.25 diameter may not be enough pitch and a 14.25 X 19 4 blade prop may be a better choice. On the other hand, Powertech makes a 4 blade Offshore prop in the same 15.25 diameter as my current prop. This is the same model I have on my motor now only one has 3 blades and the other has 4. Maybe if I stick to the same brand, model, diameter and pitch but switch to 4 blades instead of three I will drop the 200 RPM and get to the 6000 RPM mark I desire.
Tom W Clark	posted 04-11-2006 12:12 AM ET (US) Perry, Yes, I think that if there is a four blade version of what you have then yes, you will reduce your RPM and gain some thrust. But I have to say that a four blade prop with a 15-1/4" diameter is a VERY large prop. On a 135 HP motor it is even more so. I will also tell you quite honestly, that you will not know what works until you try it out. I have been surprised several times now. Since you are owed this prop from your dealer, he should let you trial them until you find what works best for you.
Tom W Clark	posted 04-11-2006 01:12 AM ET (US) Perry, Crunching some numbers I think your best bet would be to select a 14-1/4" x 19" pitch prop. That seems to fit best with other performance reports I've been looking at. I have to say that I am VERY impressed by the 45 MPH top speed of your Honda 135 on the Outrage 190. That's more or less as fast as a (much lighter) classic Outrage 18 with a classic 150 HP two stroke!
Perry	posted 04-11-2006 01:34 AM ET (US) OK Tom, I'll first try the 14-1/2 X 19 4 blade prop. I agree that 15-1/2 diameter is rather large but the BF135 uses the same gear case as the BF225 and shares the same props. I have been quite pleased with the performance of this motor. It is essentially the same motor as the BF150 minus the VTEC. I have seen a best of 46.7 MPH (GPS) on a flat ocean with a 1/4 tank of gas and myself aboard. A two way average of 45 MPH is easily achieved. Will the 4 blade prop provide better fuel mileage at cruise? I get over 6 MPG with the 3 blade prop @ 3500 RPM and 25 MPH as it is but more is always better.
Perry	posted 04-11-2006 03:10 AM ET (US) I meant to say I'll first try a 14-1/4 X 19 pitch prop. And I agree that a 15-1/4 diameter is rather large.
Tom W Clark	posted 04-11-2006 10:58 AM ET (US) Perry, It is very possible that a four blade propeller will provide better fuel economy, though at your current 6 MPG, I am very jealous ;-)
Sal DiMercurio	posted 04-11-2006 10:12 PM ET (US) Perry, flat calm water is poison for Whalers. Optimum racing water is 18" chop real close together so you can get some air under her. Makes a difference of at least 5 mph on the top end. On dead flat water the boat sticks like glue even trimmed out to maximum because there's no air pockets to break that suction loose. There's absolutly no need for a 15.25 diameter prop for that rig. When you get over 21 ft & your engine has the power to twist one, than you start looking into a bigger diameter such as a 15.25. Sal
Perry	posted 04-12-2006 12:48 AM ET (US) Sal, I agree that 15.25" diameter is overkill for a 19 foot Whaler with 135 HP. That is one reason why I'm getting a prop in 14.25 diamerter. I should have been more clear about what I consider a flat ocean. I was referring to 6-12 inch wind chop inside a very large bay.
bigjohn1	posted 04-12-2006 07:48 AM ET (US) Perry, I replaced my stock Black Max six months ago with a 4-blade Trophy Plus (170 MONTAUK/Merc 115efi). Like jimh, I have experienced a bit of vibration. It seems to come on right around 800 rpm's but is gone at around 1,100 rpm's. I will live with it for now though as the prop definitely has increased my low-end power and does indeed help me plane at a lower rpm.
Sal DiMercurio	posted 04-12-2006 02:12 PM ET (US) Bigjohn, thats strange, because a 4 blade is normally smoother than a 3 blade, & a 5 blade is smoother yet. It is possible [ but not probable ] that both you & Jim's props were not ballanced right. Strange........... I would say it was the engine vibrating at idle speed, but if it didn't with the 3 blade on it, than that's not the problem. Sal
bigjohn1	posted 04-13-2006 12:03 AM ET (US) I hear ya load and clear Sal on 4-blades are supposed to be smoother. Since I bought my Trophy prop from a custom marine performance shop, I had them check the balance when I bought it (just to be sure). I surely thought I would see less vibration but that has not been the case - at least not in the rpm range I mentioned. Confusing to say the least!
Perry	posted 04-14-2006 06:56 PM ET (US) Tom, Sal, I know both of you say that a 15- 1/4 diameter prop is too large for the 190 Outrage. This seems logical to mee too but when I went to Boston Whaler's performance data for the 190 Outrage, I notice that all 4 motors that are offered on this hull come from the factory with a 15- 1/4 diameter prop. I figure Boston Whaler rigs these boats for maximum performance and efficiency. Why would they put on a 15-1/4 diameter prop if it was too large? I know both of you have lots of experience with Whalers and props so I thought either or both of you could shed some light on this quandry.
Sal DiMercurio	posted 04-14-2006 07:35 PM ET (US) I don't even think a 15.25 diameter prop will clear the antivent plate on a 130 hp engine. 100 - 140 hp engines normally run 13.50 dia 15.25 dia is for "V"6 engines & inboard/outboards. Unless I'm missing something here. Don't forget Boston Whaler is selling Mercs, & your running a Honda, but there shouldn't be that much clearance between the prop blades & the antivent plate to fit a 15.25 dia prop in there with enough room to clear. Sal
Perry	posted 04-14-2006 09:10 PM ET (US) Sal, My motor is a 2005 BF135 The new BF135/BF150 uses the same gear case as the BF200/BF225. Thus the larger diameter props. Mine came from the dealer with a 15- 1/4 X 17 prop.
Sal DiMercurio	posted 04-15-2006 11:53 AM ET (US) I found out years ago, many dealers will put a certain prop on new engines, just because that is the prop they had in stock, or they got a deal on 6 of them for the price of 2, & now they stick them on any engine they fit on & tell the customer thats the right one. For instance, in 1992 I bought a Johnson 150 for my "V"20 & the dealer put on a 15 x 16 OMC prop., telling me it's the right one. Well, I know a little about props & saw that my rpms were in the right place, but my speed should have been better. I changed that prop to a Stiletto 14.25 x 17 & picked up about 5 mph & my engine ran easier. Later in years after they went out of business, I asked them why they put that 15 x 16 s/s OMC prop on my engine & the answer was, ..."we got a good deal on them & we had 6 of them in stock"......... Nothing is impossible. Sal
Tom W Clark	posted 04-15-2006 06:27 PM ET (US) Perry, I don't think a 15-1/4" diameter propeller on your boat is too large...necessarily. I do think that a FOUR blade 15-1/4" prop on your boat would be to large. It has nothing to do with clearance; as you note the prop you had fit just fine. Let's look at some precedents. The 15-1/2" props on the Mercury equipped Outrage 190s are all Mercury Mirage Plus propellers. These are just great props (and one I would have recommended for your boat.) But they are three blade propellers, not four. I have found that the Mirage Plus's larger diameter works well to contribute stern lift which helps larger boats. A 135 HP motor is on the bottom end of motors that will work well with the Mirage Plus. Your Honda 135 may, it may not, be able to handle it but I think it would be worth a try. Out of the six sets of props I have tried on my own boat, the Mirage Pluses have yielded the best handling and fuel economy. I have yet to try a pair of 19" Rev 4s or High Fives. The Yamaha Saltwater Series propellers are very similar in design to the Mirage Plus. A large diameter, three blade high performance propeller used on 150 HP motors and larger. It is worth noting that Yamaha does NOT recommend their Saltwater Series propellers for their F150 four stroke. The implication being that it is really not enough motor to turn a large prop like that. I would think that your 135 HP Honda wouldn't be much MORE powerful than the Yamaha F150, but it may have a lower gear ratio which would tend to accommodate a larger diameter prop. At any rate this is all relative to three blade propellers and you are talking about moving to a four blade prop. I do not think that a 15-1/4" diameter four blade propeller is well advised. As is always the case, you won't really know until you try.
Perry	posted 04-16-2006 03:22 AM ET (US) I spoke to my dealer today. I have a 14-1/4 X 19 X 4 on order. He said he will let me swap it out if I'm not pleased with it's performance. I will post the results when they become available.