Honda 4 stroke 90hp prop question

rb8484

Petty Officer 2nd Class
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Jun 17, 2009
Messages
135
I have a 2001 Honda 90hp 4 stroke on my bennington pontoon. Pontoon is a 22 footer.
I would like to see if I can get more speed out of it, right now I can pop up out of the water pretty quick. The prop that is on it now is stamped with D 3x13.5x15R.
WOT I turn between 4900 t0 5000rpms. I can only get 19 to 20 mph out of it with just my wife and I. Does that sound normal or should I be able to get more out of it?
 

rb8484

Petty Officer 2nd Class
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Jun 17, 2009
Messages
135
Any help would be much appreciated! I really want to buy a different prop for this weekend!
 

steelespike

Supreme Mariner
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Apr 26, 2002
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19,069
While pontoon speeds tend to be all over the place and similar size and weight don't necessarily mean similar speeds.
Your speed does seem too low for a 90 on a 22ft.We need your wot rpm and gps speed.The 15" prop may be too much.
I couldn't find any 90 hp pontoon tests but I did find a number of 17' outboards running 17" and one with a 15" prop.
Further research different brand similar gear ratio yours 2.33 theirs 2.36.
Speeds ranged from about 27 to about 23 all with a 15" prop.
Your max rpm rating is higher at 6300 so you might be able to run less prop and get more rpm.
Depends on yopur present rpm. Your motor needs to rfev easily.
 
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rb8484

Petty Officer 2nd Class
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Jun 17, 2009
Messages
135
Thanks steelespike, I was hoping you would chime in. I've been reading through the prop section of the forum, and you have helped a lot of people. Like I said above, my wot rpm is right about 5000, and my gps speed I'd 20. All on a calm day with just my wife and I. What size do you think I should go to get more speed? I hope to pick up a prop tomorrow to try this weekend.
 

rb8484

Petty Officer 2nd Class
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Jun 17, 2009
Messages
135
I called a few marinas near my, one told me I should go with a 11x14r prop, but I won't notice much difference in speed, he said 20mph is not bad. The other place I called said a 13.5x13r is where I need to be. What do you think?
 

YoungMind

Seaman
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Feb 25, 2014
Messages
69
Gotta get your RPM up. I would think (if you can find one) the Michigan Match number 031201 - 14x12 3-blade Alum would do much better. That prop is made for pontoons with extra cup and larger diameter. I would say that whatever you go with 13 pitch would be the largest, probably better to go smaller.
 

rb8484

Petty Officer 2nd Class
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Jun 17, 2009
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so whats with the 4 blade props. my Honda dealer has a 4 blade, 13.25x13 prop on the self for a good price.
 

rb8484

Petty Officer 2nd Class
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Jun 17, 2009
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YoungMind, will that help my top end speed, I am looking to better my speed
 

steelespike

Supreme Mariner
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Apr 26, 2002
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Your rpm is off by 1000 The 200 rpm per inch rule of thumb indicates a 5" reduction in pitch.
You may want to verify the tach.If we assume the tach is accurate your slip is 34%
Pontoons usually are around the low 20s. Your slip might improve with more rpm.
Perhaps that 4 blade 13" the dealer has.Should grip better and may handle better around the dock.
I think you need to check the motor out.At 13 years old it may be a little tired.
do the simple stuff first firing on all cylinders?Throttle opening all the way?
Be sure then timing is set right?
Do a compression test, note the location and condition of each plug?
 

rb8484

Petty Officer 2nd Class
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Jun 17, 2009
Messages
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The boat only has 180 hours on it, bought it last month. I took it to the dealer and had a full service done on it, including having the carbs rebuilt
 

steelespike

Supreme Mariner
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Apr 26, 2002
Messages
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So it appears the 4 bld. 13 is a reasonable approach. At least it should improve the rpm and being a 4 blade it may grip better and improve the slip.
Is there any chance there is water in the tubes. Does it sit really low at rest?
Do you have any venting problems(some call it cavitation) If no problems the motor may be too low. Raising it may help if it is excessively low.
But don't expect miracles.Have you tried moving weight around,trimming up or down?
There is a add on toon like devise I think called something like "Easy Glide" Makes the pontoon respond almost like a runabout.
You can skin the underside for less drag.
 

YoungMind

Seaman
Joined
Feb 25, 2014
Messages
69
YoungMind, will that help my top end speed, I am looking to better my speed

Unfortunately it might be very hard to get much better speed out of a pontoon without going larger in HP. Getting a 4-blade that will maximize the power of your engine will surely make your boating more enjoyable.
 
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