27 Full Cabin: Twin 225-HP Yamaha Four-stroke: Propeller Selection

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Author Topic:   27 Full Cabin: Twin 225-HP Yamaha Four-stroke: Propeller Selection

lucas posted 03-20-2006 09:40 PM ET (US)
I have just hung twin Yamaha 225-HP four-stroke motors on my 1988 Boston Whaler 27 Full Cabin. I am using the 17-inch pitch propellers that were on the 1988 Yamaha 200-HP outboard motorss that came with the boat. I need to push the new Yamaha four-stroke 225-HP motors 5,400-RPM to get a comfortable cruise. I feel that, if I changed propellers, maybe I could be more fuel efficient. I would appreciate any input on the matter.
Thanks. Lucas
Tom W Clark posted 03-20-2006 09:47 PM ET (US)
Lucas,
It would be helpful if you told us:
- How fast the boat used to go with the 200s at WOT.
- Exactly which 17" pitch props you have now.
lucas posted 03-20-2006 10:07 PM ET (US)
Tom
I wish I could. I bought the boat with engines that had bad lower units so I never actually ran it with those old engines. I would suspect from the rest of the boat that the props were 1988 originals. Lets say at 5400 we ran at 34kts(ballpark) with the old props on the new 225fs.
thanks
lucas
Tom W Clark posted 03-20-2006 10:12 PM ET (US)
Lucas,
Well, the props will have the part number on them.
Can you tell us if they are polished stainless steel? Painted black (or formerly painted black)?
You could measure the diameter.
I would suspect the boat will do about 40 MPH with those 17" props. Try them out and report back with the data. At that point we can make some recommendations.
lucas posted 03-20-2006 10:20 PM ET (US)
they are black and I will report back
-lucas
jimh posted 03-20-2006 11:06 PM ET (US)
For some reasonable basis of assessment, it would be good to know:
--propeller pitch and diameter
--engine recommend speed range for Wide Open Throttle (WOT)
--engine gear ratio
Please report boat speed as a function of engine speed at about 500-RPM increments from idle to WOT.
Tom W Clark posted 03-20-2006 11:11 PM ET (US)
If they are painted black and are 17" pitch, I suspect they are Yamaha M series propellers. I think you will find a "17-M" stamped on hub near the diffuser ring.
These props have a 13.75" diameter and a 17" pitch.
The Yamaha F225 had a 5000-6000 RPM WOT speed range and a 2:1 gearcase ratio.
Peter posted 03-21-2006 01:07 PM ET (US)
Does this 27 FC have a Whaler Drive? Having experimented with several different sets of propellers on my 27 Whaler WD, the 4 blade propellers seem to provide the best overall performance. I suspect that the same will be true for the 27 Whaler FC.
With the 4-blades you will experience increased cruising comfort, similar fuel economy and much greater docking control.
Deanster posted 03-21-2006 06:09 PM ET (US)
[This messages seems to be addressed to Lucas]
Hi - I'm looking at re-powering for my 27, and I'm looking at either Yamaha or Suzuki four-stroke motors or perhaps E-TEC two-stroke motors, if I can find a decent price.
How are you finding your 225's? It sounds as if you're feeling a bit underpowered. Or is it just that your props aren't transmitting the power you've got very efficiently?
I'm a giant fan of four blade props for the larger Boston Whaler boats. I actually had the five-blade Mercury High Five props on a Outrage 22 (prior owner had 'em, I kept 'em), and while they limited top speed quite a bit, I've never had more connection to the water, excellent acceleration, and AMAZING low-speed maneuverability.
Four-blade props are now my standard for 25-foot Boston Whaler boats.
In any case, I'd appreciate your thoughts about your re-power. Any advice to share?
jimh posted 03-21-2006 07:45 PM ET (US)
This thread has been moved to the PERFORMANCE area from another area. Articles whose topic is the performance of Boston Whaler boats and how to improve it should be posted to the PERFORMANCE area.
handn posted 03-22-2006 09:14 AM ET (US)
My 305 Conquest with 225 Yamamerc efi 4-strokes runs 17p Mercury Revolution 4's. I couldn't be more pleased with the performance of those props.
Other than the black cowl and the binacle, the Yamamerc efi 4-strokes are 100% Yamaha so the props should fit.
At wot throttle, my engines are turning 5400 rpm.
My only question is 17p too little for your boat or would you be better off with 19p. The 305 weighs 8500 dry and is over 10,000 with engines passengers and fuel. I would guess with a lighter boat, the engines would be turning 5800 rpm or better with 17p props and pushing the boat 40 mph plus.
JMR posted 03-22-2006 09:38 AM ET (US)
I have a 1988 Whaler 27 WD with twin 200 hp Johnson Ocean Runners from 1997 (183 cu. inch/149.2 Kw)-- center & two saddle tanks with 310 gallons, radar arch, stern seat, but no other extra weight. My very limited experience on this boat late last fall seemed to confirm what the seller had indicated as to performance, namely:
WOT 5,500 rpm gave about 35 mph on the GPS -- with 15x17 OMC SST props (431930/391290) and a 1.86:1 gear ratio. Using the propeller calculator I find that this makes the slip rate about 26%.
The tanks were mostly empty & there were two adults on board at 195lbs each. My WOT rpm is in the middle of the factory range of 5-6,000 rpm & I understand from Peter and others on this site that I should try to get it up into the higher end of the range.
The low speed handling for docking is awful so I am tempted by the promise of 4-blades but can I reasonably expect to use 17' pitch 4-blades given the rule of thumb that the extra blade will drop my rpm? The only 16' pitch 4-blade I have seen is the Apollo by Michigan Wheel, as for the BRP Cyclone I haven't seen specs. yet, and the Mercury Rev 4 is 17'
I understand that it is a question of testing and testing with different props etc but any guesses on (a) what the problem might be with my SSTs and (b) what I might expect to succeed in the 4-blades?
Peter posted 03-22-2006 10:45 AM ET (US)
JMR -- A few suggestions based on my experience when I got my 27 and the top speed was 34 MPH. It's now 45 MPH.
1. Check to make sure that your trim tabs are fully retracted when you are trying to gauge top speed. When I got my 27, the hydraulic trim tab pump was shot and the tabs were in the deployed position, one more than the other, driving the bow down into the water creating excessive drag.
2. Check the toe-in alignment of your motors. Specification calls for 1/2 to 3/4 inch toe-in alignment which means the distance between the noses of the gearcases is 1/2 to 3/4 shorter than the distance between the centers of the prop shaft. When I got my 27, the motors were incorrectly aligned with about 3/4 inch toe-out, not toe-in! Some riggers confuse toe-in and toe-out settings.
3. Check engine height. The center (from port to starboard) of the anti-vent plate should be just slightly higher than bottom of the boat at that point.
4. Replace the 15 x 17 SSTs with 4 blade propellers. I would try the 14 1/4 x 17 Cyclones, the 14 5/8 x 17 Revolution 4s (this is what I'm running right now) or also the PowerTech 4-blade propellers (you'd have to ask PT what pitch to use because their pitch scale is different than OMCs, probably a 15 inch pitch would cut it).
You will find that with the increased traction of the 4-blade propellers that the ride of the boat is much better (it doesn't lose its momentum as easily in a chop), that docking is significantly easier, and that you can maintain a low speed plane much better. I'll bet that your 27 falls off plane at close to 3700 RPM right now with the SSTs and that they have a tendency to blow out fairly easily.
Peter posted 03-22-2006 10:48 AM ET (US)
I should add that the tie-bar allows for about 1/4 inch adjustment on the toe-in/out alignment. I had to have about 1/2 inch cut off one of the ends of the tie-bar to go from the incorrect toe-out to the correct toe-in alignment.
JMR posted 03-22-2006 11:54 AM ET (US)
Peter -- I am most grateful for the advice and I will try to follow it and keep you posted.

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Author	Topic: 27 Full Cabin: Twin 225-HP Yamaha Four-stroke: Propeller Selection
lucas	posted 03-20-2006 09:40 PM ET (US) I have just hung twin Yamaha 225-HP four-stroke motors on my 1988 Boston Whaler 27 Full Cabin. I am using the 17-inch pitch propellers that were on the 1988 Yamaha 200-HP outboard motorss that came with the boat. I need to push the new Yamaha four-stroke 225-HP motors 5,400-RPM to get a comfortable cruise. I feel that, if I changed propellers, maybe I could be more fuel efficient. I would appreciate any input on the matter. Thanks. Lucas
Tom W Clark	posted 03-20-2006 09:47 PM ET (US) Lucas, It would be helpful if you told us: - How fast the boat used to go with the 200s at WOT. - Exactly which 17" pitch props you have now.
lucas	posted 03-20-2006 10:07 PM ET (US) Tom I wish I could. I bought the boat with engines that had bad lower units so I never actually ran it with those old engines. I would suspect from the rest of the boat that the props were 1988 originals. Lets say at 5400 we ran at 34kts(ballpark) with the old props on the new 225fs. thanks lucas
Tom W Clark	posted 03-20-2006 10:12 PM ET (US) Lucas, Well, the props will have the part number on them. Can you tell us if they are polished stainless steel? Painted black (or formerly painted black)? You could measure the diameter. I would suspect the boat will do about 40 MPH with those 17" props. Try them out and report back with the data. At that point we can make some recommendations.
lucas	posted 03-20-2006 10:20 PM ET (US) they are black and I will report back -lucas
jimh	posted 03-20-2006 11:06 PM ET (US) For some reasonable basis of assessment, it would be good to know: --propeller pitch and diameter --engine recommend speed range for Wide Open Throttle (WOT) --engine gear ratio Please report boat speed as a function of engine speed at about 500-RPM increments from idle to WOT.
Tom W Clark	posted 03-20-2006 11:11 PM ET (US) If they are painted black and are 17" pitch, I suspect they are Yamaha M series propellers. I think you will find a "17-M" stamped on hub near the diffuser ring. These props have a 13.75" diameter and a 17" pitch. The Yamaha F225 had a 5000-6000 RPM WOT speed range and a 2:1 gearcase ratio.
Peter	posted 03-21-2006 01:07 PM ET (US) Does this 27 FC have a Whaler Drive? Having experimented with several different sets of propellers on my 27 Whaler WD, the 4 blade propellers seem to provide the best overall performance. I suspect that the same will be true for the 27 Whaler FC. With the 4-blades you will experience increased cruising comfort, similar fuel economy and much greater docking control.
Deanster	posted 03-21-2006 06:09 PM ET (US) [This messages seems to be addressed to Lucas] Hi - I'm looking at re-powering for my 27, and I'm looking at either Yamaha or Suzuki four-stroke motors or perhaps E-TEC two-stroke motors, if I can find a decent price. How are you finding your 225's? It sounds as if you're feeling a bit underpowered. Or is it just that your props aren't transmitting the power you've got very efficiently? I'm a giant fan of four blade props for the larger Boston Whaler boats. I actually had the five-blade Mercury High Five props on a Outrage 22 (prior owner had 'em, I kept 'em), and while they limited top speed quite a bit, I've never had more connection to the water, excellent acceleration, and AMAZING low-speed maneuverability. Four-blade props are now my standard for 25-foot Boston Whaler boats. In any case, I'd appreciate your thoughts about your re-power. Any advice to share?
jimh	posted 03-21-2006 07:45 PM ET (US) This thread has been moved to the PERFORMANCE area from another area. Articles whose topic is the performance of Boston Whaler boats and how to improve it should be posted to the PERFORMANCE area.
handn	posted 03-22-2006 09:14 AM ET (US) My 305 Conquest with 225 Yamamerc efi 4-strokes runs 17p Mercury Revolution 4's. I couldn't be more pleased with the performance of those props. Other than the black cowl and the binacle, the Yamamerc efi 4-strokes are 100% Yamaha so the props should fit. At wot throttle, my engines are turning 5400 rpm. My only question is 17p too little for your boat or would you be better off with 19p. The 305 weighs 8500 dry and is over 10,000 with engines passengers and fuel. I would guess with a lighter boat, the engines would be turning 5800 rpm or better with 17p props and pushing the boat 40 mph plus.
JMR	posted 03-22-2006 09:38 AM ET (US) I have a 1988 Whaler 27 WD with twin 200 hp Johnson Ocean Runners from 1997 (183 cu. inch/149.2 Kw)-- center & two saddle tanks with 310 gallons, radar arch, stern seat, but no other extra weight. My very limited experience on this boat late last fall seemed to confirm what the seller had indicated as to performance, namely: WOT 5,500 rpm gave about 35 mph on the GPS -- with 15x17 OMC SST props (431930/391290) and a 1.86:1 gear ratio. Using the propeller calculator I find that this makes the slip rate about 26%. The tanks were mostly empty & there were two adults on board at 195lbs each. My WOT rpm is in the middle of the factory range of 5-6,000 rpm & I understand from Peter and others on this site that I should try to get it up into the higher end of the range. The low speed handling for docking is awful so I am tempted by the promise of 4-blades but can I reasonably expect to use 17' pitch 4-blades given the rule of thumb that the extra blade will drop my rpm? The only 16' pitch 4-blade I have seen is the Apollo by Michigan Wheel, as for the BRP Cyclone I haven't seen specs. yet, and the Mercury Rev 4 is 17' I understand that it is a question of testing and testing with different props etc but any guesses on (a) what the problem might be with my SSTs and (b) what I might expect to succeed in the 4-blades?
Peter	posted 03-22-2006 10:45 AM ET (US) JMR -- A few suggestions based on my experience when I got my 27 and the top speed was 34 MPH. It's now 45 MPH. 1. Check to make sure that your trim tabs are fully retracted when you are trying to gauge top speed. When I got my 27, the hydraulic trim tab pump was shot and the tabs were in the deployed position, one more than the other, driving the bow down into the water creating excessive drag. 2. Check the toe-in alignment of your motors. Specification calls for 1/2 to 3/4 inch toe-in alignment which means the distance between the noses of the gearcases is 1/2 to 3/4 shorter than the distance between the centers of the prop shaft. When I got my 27, the motors were incorrectly aligned with about 3/4 inch toe-out, not toe-in! Some riggers confuse toe-in and toe-out settings. 3. Check engine height. The center (from port to starboard) of the anti-vent plate should be just slightly higher than bottom of the boat at that point. 4. Replace the 15 x 17 SSTs with 4 blade propellers. I would try the 14 1/4 x 17 Cyclones, the 14 5/8 x 17 Revolution 4s (this is what I'm running right now) or also the PowerTech 4-blade propellers (you'd have to ask PT what pitch to use because their pitch scale is different than OMCs, probably a 15 inch pitch would cut it). You will find that with the increased traction of the 4-blade propellers that the ride of the boat is much better (it doesn't lose its momentum as easily in a chop), that docking is significantly easier, and that you can maintain a low speed plane much better. I'll bet that your 27 falls off plane at close to 3700 RPM right now with the SSTs and that they have a tendency to blow out fairly easily.
Peter	posted 03-22-2006 10:48 AM ET (US) I should add that the tie-bar allows for about 1/4 inch adjustment on the toe-in/out alignment. I had to have about 1/2 inch cut off one of the ends of the tie-bar to go from the incorrect toe-out to the correct toe-in alignment.
JMR	posted 03-22-2006 11:54 AM ET (US) Peter -- I am most grateful for the advice and I will try to follow it and keep you posted.