Repowering 20' Weeres Pontoon... Need Advice

[FlyboyTR]

Re: Repowering 20' Weeres Pontoon... Need Advice

A 2002 motor must be oil injected should do well trolling.
One of the things that can cause a 4 stroke to make oil is trolling.

Yes, if my choice is a 2-stroke, it will have to be oil-injected. I do believe they do better at idling than a pre-mix would...since the oil is metered based upon throttle position. Also, using a synthetic oil reduces the smoke, etc.

 

[Silvertip]

Re: Repowering 20' Weeres Pontoon... Need Advice

Since you mentioned long periods of idling/trolling there is an issue with 4-strokes (some more than others) that you need to be aware of. "Making oil" means when checking oil level you see a gradual increase on the dip stick. This is not a good thing since that extra oil is not really oil but unburned fuel. This is due to the engine running cool and is made even worse if the wrong prop is installed and the engine is lugging (not able to reach the upper end of the manufacturers rpm band at wide open throttle. This diluted oil means the engine is not being lubricated properly and excessive wear occurs. Two strokes don't have that problem.

Then the fuel economy misinformation enters the picture. If you compare a 90 2 stroke and 90 four stroke on the exact same boat you will see that at wide open throttle, both engines burn within a whisker of the same amount of fuel. It is at idle and light throttle settings that the four storke has a significant advantage. If you study fuel consumption charts (Yamaha has them in the "performance Bulletin" section of their web site) you will see that if you compare fuel consumption at any specific RPM, the four stroke burns less fuel. However, if you compare fuel consumption at the same boat speeds, you will see these numbers are again very close. Why? Because a two stroke almost always is pushing a boat faster at the same rpm as a four stroke. Understand what you are looking at when comparing two and four stroke motors.

 

[steelespike]

Re: Repowering 20' Weeres Pontoon... Need Advice

Well said Silvertip.

 

[FlyboyTR]

Re: Repowering 20' Weeres Pontoon... Need Advice

Since you mentioned long periods of idling/trolling there is an issue with 4-strokes (some more than others) that you need to be aware of. "Making oil" means when checking oil level you see a gradual increase on the dip stick. This is not a good thing since that extra oil is not really oil but unburned fuel. This is due to the engine running cool and is made even worse if the wrong prop is installed and the engine is lugging (not able to reach the upper end of the manufacturers rpm band at wide open throttle. This diluted oil means the engine is not being lubricated properly and excessive wear occurs. Two strokes don't have that problem.

Then the fuel economy misinformation enters the picture. If you compare a 90 2 stroke and 90 four stroke on the exact same boat you will see that at wide open throttle, both engines burn within a whisker of the same amount of fuel. It is at idle and light throttle settings that the four storke has a significant advantage. If you study fuel consumption charts (Yamaha has them in the "performance Bulletin" section of their web site) you will see that if you compare fuel consumption at any specific RPM, the four stroke burns less fuel. However, if you compare fuel consumption at the same boat speeds, you will see these numbers are again very close. Why? Because a two stroke almost always is pushing a boat faster at the same rpm as a four stroke. Understand what you are looking at when comparing two and four stroke motors.

Thanks for the making oil explanation. Good info! I will check the Performance Bulletin section of the Yamaha website.

I am finding only a few 90's for sale. Any comments regarding older models? I have found a 97 model in good condition for $1,700. I don't have any problem with an older engine...since the 90HP 2 strokes are all pretty much the same. With that said...what specifics should I be looking for in determining the health condition of a used engine. Thanks!

 

[lncoop]

Re: Repowering 20' Weeres Pontoon... Need Advice

I contacted my insurance company this afternoon. They will not insure the toon if the motor is larger than what is posted by the manufacturer.

This quote should be a sticky.

 

[Silvertip]

Re: Repowering 20' Weeres Pontoon... Need Advice

I am finding only a few 90's for sale. Any comments regarding older models? I have found a 97 model in good condition for $1,700. I don't have any problem with an older engine...since the 90HP 2 strokes are all pretty much the same. With that said...what specifics should I be looking for in determining the health condition of a used engine. Thanks!

Compression test is mandatory in my view as is an on-water test or as a minimum, a test tank. I will pay junk prices for an engine that the owner will not allow me to run (or attempt to run).

 

[EGlideRider]

Re: Repowering 20' Weeres Pontoon... Need Advice

Thanks for the making oil explanation. Good info! I will check the Performance Bulletin section of the Yamaha website.

I am finding only a few 90's for sale. Any comments regarding older models? I have found a 97 model in good condition for $1,700. I don't have any problem with an older engine...since the 90HP 2 strokes are all pretty much the same. With that said...what specifics should I be looking for in determining the health condition of a used engine. Thanks!

As said before, most 2-strokes are pretty much bullet proof if the correct fuel/oil ratio is maintained. Check the compression of each cylinder and if they are ok, then go for it. If it has carbs and they have never been rebuilt, then I would recommend that you do so.

 

[FlyboyTR]

Re: Repowering 20' Weeres Pontoon... Need Advice

Compression test is mandatory in my view as is an on-water test or as a minimum, a test tank. I will pay junk prices for an engine that the owner will not allow me to run (or attempt to run).

I was contacted today by a local Yamaha dealer. He's got a 98 model that he took on trade 6 monhts ago and it's just been sitting in the corner of the shop. It is not on a boat. Compression was checked while I watched. It was approximately 130-135 for all three. The engine has a clean overall appearance (without actually being cleaned/detailed. It appears to have all new head/cover bolts and the head cover (water jacket cover) appears to be new. The dealer said that he had provided service on this engine up until 5 years ago...after that, unknown. They are going to hook it up tomorrow and run it. It is a pre-mix (no oil injection). I believe I can buy it for 2K, and he will mount it on the pontoon boat.

While I will not have any in-water test, nor a test tank...I feel pretty good about this one. While I was wanting oil injected for convenience... with this motor I wont have to travel hundreds of miles, transport a motor and then try to mount the thing. One drawback is that there is no propeller. So I am at a loss as to what size to be looking for.

 

[wagnerz]

Re: Repowering 20' Weeres Pontoon... Need Advice

One thing you can negotiate that many people don't even think about, especially with the dealer, is ask for a 60 or 90 day warranty on the engine. And then run the hell out of the motor in the first 60 days. Well maybe not run it that hard, but put it to use and test that motor out. That way you can have some assurance that if the motor is crap he will repair it or give you your money back.

 

[Jeep Man]

Re: Repowering 20' Weeres Pontoon... Need Advice

I was contacted today by a local Yamaha dealer. He's got a 98 model that he took on trade 6 monhts ago and it's just been sitting in the corner of the shop. It is not on a boat. Compression was checked while I watched. It was approximately 130-135 for all three. The engine has a clean overall appearance (without actually being cleaned/detailed. It appears to have all new head/cover bolts and the head cover (water jacket cover) appears to be new. The dealer said that he had provided service on this engine up until 5 years ago...after that, unknown. They are going to hook it up tomorrow and run it. It is a pre-mix (no oil injection). I believe I can buy it for 2K, and he will mount it on the pontoon boat.

While I will not have any in-water test, nor a test tank...I feel pretty good about this one. While I was wanting oil injected for convenience... with this motor I wont have to travel hundreds of miles, transport a motor and then try to mount the thing. One drawback is that there is no propeller. So I am at a loss as to what size to be looking for.

Don't sweat the prop thing too much. If the motor wasn't on a toon previously, it wouldn't have been propped correctly anyway. It is a 20" shaft, right?

 

[FlyboyTR]

Re: Repowering 20' Weeres Pontoon... Need Advice

Excellent point about the warranty. I will ask and push for that. Yes, 20" shaft.

 

[Silvertip]

Re: Repowering 20' Weeres Pontoon... Need Advice

You have a very good reference on the Yamaha web site for propeller selection. Remember the Performance Bulletins I mentioned awhile back. Pick a 20 foot toon, 90 hP 2 stroke engine and you will be presented with test reports for those models complete with fuel consumption and prop selection. Can't be simpler. You don't need to see the exact pontoon. 20 footers are pretty standard in weight and equipment.

 

[FlyboyTR]

Re: Repowering 20' Weeres Pontoon... Need Advice

You have a very good reference on the Yamaha web site for propeller selection. Remember the Performance Bulletins I mentioned awhile back. Pick a 20 foot toon, 90 hP 2 stroke engine and you will be presented with test reports for those models complete with fuel consumption and prop selection. Can't be simpler. You don't need to see the exact pontoon. 20 footers are pretty standard in weight and equipment.

OK. I checked the Yamaha site. There were no 20' toons listed with a 90 HP. I did note they used the same engine/prop combo on everything they tested in the pontoon ,90 HP, 2 stroke category. The prop was a 13 5/8 x 13. ...I'm still at a loss.

 

[EGlideRider]

Re: Repowering 20' Weeres Pontoon... Need Advice

OK. I checked the Yamaha site. There were no 20' toons listed with a 90 HP. I did note they used the same engine/prop combo on everything they tested in the pontoon ,90 HP, 2 stroke category. The prop was a 13 5/8 x 13. ...I'm still at a loss.

It is not unusual to try a couple of props before getting one to perform in the rated WOT RPM range of your engine. IMHO, the 13 5/8 X 13 is a very good starting point for your boat/engine combo and hopefully will be your last.

 

[lncoop]

Re: Repowering 20' Weeres Pontoon... Need Advice

It is not unusual to try a couple of props before getting one to perform in the rated WOT RPM range of your engine. IMHO, the 13 5/8 X 13 is a very good starting point for your boat/engine combo and hopefully will be your last.

I agree. Also, if you buy the Yammy from that dealer ask him to throw in that^prop. If he doesn't no biggie, but it never hurts to ask. If it turns out not to be the best choice he'll most likely let you swap out until you get it right (within reason of course). If he doesn't let you swap out just buy another one and keep the thirteen as a spare. I had a 98 Yammy fifty horse. It was a great little motor.

 

[Silvertip]

Re: Repowering 20' Weeres Pontoon... Need Advice

And what you found for a prop is about right. 13-5/8 x 13 is in the ballpark for that combination. Remember, pontoons are barges - not planning hulls. If you check 90 HP 4-strokes on 22 footers they use a similar prop because the gear ratios are similar. Don't make this harder than it is. Yamaha also makes a pontoon-specific prop so pop for one of those. And by the way -- if you checked the fuel consumption you would have confirmed what I said earlier about fuel consumption.

 

[FlyboyTR]

Re: Repowering 20' Weeres Pontoon... Need Advice

Guys...thanks for all the help! The dealer is going to give me a 30 day warranty on the motor. He is also installing a new water pump and changing the gear oil. I have a long-time friend that is a Yamaha dealer. I was talking to him and he offered to let me play with whatever props he had laying around. He laughed and said that he had 8-10 props I could use for testing. That works for me.

Glad to hear the 13 5/8x13 is in the ball park. Yes, I did check the fuel numbers...interesting!

When I chewed up the aluminum prop on the 50, I replace it (same size) with a Solas New Saturn. It was dead-on and gave me 2 MPH more at WOT, same RPM (+ or - 50) and I no longer had the ventilation issue I did with the stock prop. Oh... with 6 people on the boat and loaded with gear, etc, it would still make 16-17 MPH at WOT. Anyway...I was very impressed with that prop. Thanks again!

 

[FlyboyTR]

Re: Repowering 20' Weeres Pontoon... Need Advice

Update... I purchased the 90 hp. Having some idling problems...but they are working on that today. I borrowed a 13x19 aluminum prop. They said it was way too big (pitch), but for the purposes of running the motor...it would be ok. I ran it yesterday. At WOT and trimmed I hit 31 MPH. I do not know what RPM...since I don't have a tach (looking at getting one today). The prop that is on order is the Solas New Saturn (stainless) 13 3/4 x13. I am concerned that it may be underpropped with that one. If I mount and use it, I can't return it to Iboats.com!

 

[Silvertip]

Re: Repowering 20' Weeres Pontoon... Need Advice

You are strongly advised to install a tachometer. It is an essential instrument when experimenting with props. If you don't know what the WOT rpm is you have no idea if you are lugging the engine, over-reving it, or if it is spot on. The optimum prop is one that allows the engine to run at or very near the top of the manufacturers recommended WOT rpm with what you will consider an average load. Speed and economy will be whatever that prop delivers so DO NOT shoot for maximum speed. The proper prop and engine rpm determines that.

 

[lncoop]

Re: Repowering 20' Weeres Pontoon... Need Advice

What Silvertip said. Operating within the proper RPM band is essential to the health of your motor. Get a tachadero. Regarding the prop from iboats; just betwixt us girls I bought one from them last summer and it turned out to be wrong for my rig. I apprised them of the situtation, advised them the prop still looked new and I had all the packaging, and told them I knew their policy when I ordered it and understood completely if they weren't willing to take it back. The CSA told me to send it back and she'd see what she could do. Two weeks later they credited my card with a full refund. Mileage may vary.