Yamaha 60hp to 90hp on a pontoon

Reg312

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I have a 2005 20' G3 pontoon with same year 60hp yamaha 2 stroke. Transom rated for 100hp. I just don't have enough power to give my grandkids a good ride on the tube. Would moving up to 90hp Yamaha be worth it? Both the 60 and 90 are 3 cylinder motors. I don't need much .... maybe 5mph would do it. With the 60 I can get up to 18mph with 4 people no tubers. Any input would be helpful ..... thanks!
 

Sea Rider

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Prop the motor right to run towards its max wot rpm range factory stated. Down issue is tubbers + 4 on board at same time. How about leaving those 4 souls at terra firme and going out with the kids for tubbing, afterwords can pick the 4 souls and have fun and not invest on a 90 HP motor.

Happy Boating
 

captmello

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I'd go with the 90 if it fits your budget, I can tow 2 tubes with my 90, with top speed of 27 mph running alone.
 

flyguy2693

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A 90hp on a 20' is almost at the top of the hp limit. You do not want to damage the transom well. A 75hp, propped correctly is the minimum for what you are trying to accomplish.
 

Sea Rider

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Or you can keep the current Yam 60 HP, buy a Propulse or Piranha type prop. It's a four blade with 5 variable pitches to choose from, can kill two birds with a single shot for the motor to run towards its max wot rpm range factory stated. These type of props will dial the correct pitch needed on water tests as loaded much faster than buying more than one traditional prop to test.

Cons: will break any blade if hitting hard any submerged object. Pros : can buy spare blades and replace any broken one in just a few minutes wherever the combo was running at. Ain't that super cool !!

Happy Boating
 

Faztbullet

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90 will work great....my 24ft is rated for 115 and has 150. Slings tube with 3 riders and 4 people on board..tops out at 34MPH GPS
 

MRS

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I have a 20ft. and run a 90ct merc. on it works great I would go with the 90.
 

Sea Rider

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Before going for a 2 stroke 90 HP motor need to post the max wort rpm the 60 HP motor achieved with four up along 2 kids being pulled on tubes. You could be lugging the motor with all that load and never knowing a thing about it. Does the motor counts with an installed dash tach ? Max speed is relative, wot rpm is all to prop right any motor for a given application.

Happy Boating
 
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captmello

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Before going for a 2 stroke 90 HP motor need to post the max wort rpm the 60 HP motor achieved with four up along 2 kids being pulled on tubes. Does the motor counts with an installed tach ? Max speed is relative, wot rpm is all to prop right any motor for a given application.

Happy Boating
while the prop on a planing hull can make dramatic differences with water sports, I would say that this boat is lacking the speed needed to scare the grandkids. it's hard to believe a prop is going to give him the extra speed he's looking for. unless, of course, he is underproped, which would not be solved with 5 blade props etc. imo.
 

Sea Rider

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As the song goes : The OP only wants a little help from... doesn't want a speed demon pontoon to scare the kids out. Untill a wot rpm run as loaded it's not reported, this post will turn very speculative. That motor/pontoon combo will benefit achieving a higher fast displacement non planing speed if correctly propped for that given load.

Personally would stay with an OEM Yam 3 blade prop with less pitch or the Propulse, Piranha alternative. It's out of this workd going straight for a higher 90 HP motor without knowing the current wot rpm range the 60 HP motor is currently revving at as loaded.

Happy Boating
 

ahicks

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The 2 stroke 60's and 90's both weigh the same, so I think you'll see a significant difference, especially if you take the time to get the right prop for the job.

The Honda 90 (4 stroke) on our 24' boat does a nice job with young kids. Can't toss them around like a ski boat could, but the young ones will still have a blast, especially if they've never done anything like that before.

If talking a new motor for this conversion, and you have the room for it, you might look into a simple 16'-18' ski boat that's a few years old. That would do a much better job, and may be even less expensive than the 60 > 90 conversion.

I just restored an aluminum 19' deck boat w/115 Johnson for our grand kids.... -Al
 
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Reg312

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90 will work great....my 24ft is rated for 115 and has 150. Slings tube with 3 riders and 4 people on board..tops out at 34MPH GPS
I have contemplated a 110 / 115 because I've found a couple at reasonable price. I know thats controversial on here so I chose not to mention that.
 

Reg312

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Jul 12, 2009
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The 2 stroke 60's and 90's both weigh the same, so I think you'll see a significant difference, especially if you take the time to get the right prop for the job.

The Honda 90 (4 stroke) on our 24' boat does a nice job with young kids. Can't toss them around like a ski boat could, but the young ones will still have a blast, especially if they've never done anything like that before.

If talking a new motor for this conversion, and you have the room for it, you might look into a simple 16'-18' ski boat that's a few years old. That would do a much better job, and may be even less expensive than the 60 > 90 conversion.

I just restored an aluminum 19' deck boat w/115 Johnson for our grand kids.... -Al
I'm looking used and a Yamaha 90 runs $3000 - $5000. But I can also sell my 60 for similar price. I've contemplated a used ski type boat but thats more upkeep, Licencing, for the few times I need it on the water. A old 70 Johnson would do fine on a 16' and affordable. Running a stock pitch blade. I only have my panel tach to go by and it say 5000 rpm WOT. Thanks
 

Reg312

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As the song goes : The OP only wants a little help from... doesn't want a speed demon pontoon to scare the kids out. Untill a wot rpm run as loaded it's not reported, this post will turn very speculative. That motor/pontoon combo will benefit achieving a higher fast displacement non planing speed if correctly propped for that given load.

Personally would stay with an OEM Yam 3 blade prop with less pitch or the Propulse, Piranha alternative. It's out of this workd going straight for a higher 90 HP motor without knowing the current wot rpm range the 60 HP motor is currently revving at as loaded.

Happy Boating
When tubing we keep a light load. 3 on the pontoon (1 adult and 1 kid) and 2 on the tube (again 1 adult and 1 kid.) I have a stock prop that runs 18 to 19 mph which I've read is close to max for that HP range. I rev at 5000 rpm according to dash gauge (I can't say if thats accurate). Will a different ptich prop or the one you recommend really give me 4+ mph more?
 

ahicks

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When tubing we keep a light load. 3 on the pontoon (1 adult and 1 kid) and 2 on the tube (again 1 adult and 1 kid.) I have a stock prop that runs 18 to 19 mph which I've read is close to max for that HP range. I rev at 5000 rpm according to dash gauge (I can't say if thats accurate). Will a different ptich prop or the one you recommend really give me 4+ mph more?
I would say not very likely. A prop turning up about 6k would give you better pulling power, and you might see an additional 1 or 2 mph.
 

Reg312

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I would say not very likely. A prop turning up about 6k would give you better pulling power, and you might see an additional 1 or 2 mph.
Thanks .... So bigger motor or 16' runabout seems to be my 2 choices. I kinda figured that but sometimes nice to get confirmation.
 
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