Repowering 20' Weeres Pontoon... Need Advice

[The Rooster]

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

Congratulations. Seems like you're back on track. Try a search here on the forum about the underdeck fuel tank. I believe it's been done !!!

 

[FlyboyTR]

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

Congratulations. Seems like you're back on track. Try a search here on the forum about the underdeck fuel tank. I believe it's been done !!!

Thanks Rooster... I so some looking!

 

[FlyboyTR]

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

I have now purchased a 2003 Yamaha F90 (four stroke) with 45 hours on it. Everything was clean as a pin. I have mounted it and used the original prop 13x17. I could only get 4000 RPM out of it. I installed the 13.75x13 Solas (the one I purchased for the 90 2-stroke) and trimmed for best RPM I was able to get 4,500. ...still too slow! I am going to try raising the engine up to its highest mounting position (I"m currently in the #2 hole from the top). I am in hopes this will help some. If it's close...I will have the prop repitched.

RPM UPDATE:
I had purchased a Tiny Tach for my RPM/prop testing. As noted obove I was onlyl able to get 4,500 RPM with the Solas prop. After I raised the engine to its highest mounting postion we did another test run (actually went fishing!). I was only able to get 4,300. I backed off the throttle just a little and now the tach read 2,800! I went back to full throttle and this time it was reading 3,400. As I continued to play I came to the realization that the Tiny Tach was not reading correctly! Sucks...

I purchased a new Yamaha round digital tach with the wiring harnesses. Running the motor on the hose, at idle the Tiny Tach was showing 600 and the Yamaha tach was showing 800. ...back to the River! Best trimmed RPM was 5,800 (This was with two people and fishing gear). GPS speed was 28 mph. So.....................

Should I leave well enough alone, or should I have the Solas prop tweaked a degree or two to gain another 200-400 RPM?

 

[lncoop]

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

I don't know the RPM band for that motor, but if you're getting 5800 I suspect you're right where you need to be.

 

[FlyboyTR]

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

I don't know the RPM band for that motor, but if you're getting 5800 I suspect you're right where you need to be.

The max RPM range for the F90 is 5,000 to 6,000. So I'm close. I'm just not sure how it's going to do when we load it down.

 

[lncoop]

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

The max RPM range for the F90 is 5,000 to 6,000. So I'm close. I'm just not sure how it's going to do when we load it down.

FWIW my tach reflects very little difference between loaded and not. Glad you're getting it sorted out.

 

[FlyboyTR]

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

FWIW my tach reflects very little difference between loaded and not. Glad you're getting it sorted out.

Thanks! I won't do anything till I have a chance to run it with a load. I was just so relieved when the new Yamaha Tach showed 5,800.

 

[FlyboyTR]

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

The new F90 continues to be a great match for our toon. Loaded, my max RPM is 5700. I may still consider having the prop tweaked a little.

I had started noticing the motor mount appeared to be sagging. My Weeres is rated for 90HP max. Further investigation revealed the two aft cross members were bending under the weight of the 400 lb F90. Those two beams are 4” apart and sit 18” forward from the aft end of the motor mount. So basically, where the motor mounts is cantilevered 18”. I contacted Weeres and received a reply that they were contacting several of their reps concerning my problem.

The next question that came out of that think-tank was; How often do you trailer your pontoon? Easy answer… Always! Usually twice a week, 20 - 60 miles each trip. Next question… Was I using a transom saver while trailering. My answer, NO!

The general consensus was that the damage was occurring while trailering, NOT while boating. OK… I purchased a transom saver and the difference was amazing. When I pulled out of our driveway the first time (I have a rain-hump across the top of our driveway) I did not have the normal bounce, bounce, bounce… that I had always felt! All of that weight swinging off the back of the boat, unsupported really was the cause of the bending cross members.

Lesson Learned… I will always have my transom saver installed when the boat is being trailered!

 

[lncoop]

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

I used a transom saver for part of the summer before last, but it was a cheapie and broke under the weight of the ninety horse Merc. I need to get another one and this time not be such a cheap bass turd about it. I usually adhere to the "buy nice or buy twice" philosophy. Not sure why I broke my own rule on that one. Oh bother. Glad to hear Weeres was so eager to help. That's often not the case with manufacturers.

 

[FlyboyTR]

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

I used a transom saver for part of the summer before last, but it was a cheapie and broke under the weight of the ninety horse Merc. I need to get another one and this time not be such a cheap bass turd about it. I usually adhere to the "buy nice or buy twice" philosophy. Not sure why I broke my own rule on that one. Oh bother. Glad to hear Weeres was so eager to help. That's often not the case with manufacturers.

The transom saver I purchased was the best one I could get locally...and I needed/wanted it ASAP. So no time to order. It is a bit small for the F90, but is working. Now that the "push" is off...I will search for a better unit. Yes, I was pleased with Weeres response and interest in my problem. They also gave me pricing on purchasing two new cross members, but suggested that if "the bend wasn't getting any worse, don't worry about it." Hummmmm? Fortunately, the bending has stopped with the use of the transom saver. But I am keeping a close eye on it!

 

[brentwalker]

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

Where do you find the hp restrictions for a given pontoon boat, especially for olders models or ones bought used?

 

[FlyboyTR]

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

Where do you find the hp restrictions for a given pontoon boat, especially for olders models or ones bought used?

All boats (since back in the 1970's...I think...) carry a weight/passenger/HP rating. It is on a small plackard about the size of an index card. These can be located anywhere on the boat, transom area, motor well, steering console, etc. If your toon does not have a plackard, I would do some internet research and try to find an exact match...or something close to what you have, length, pontoon diameter, poontoon, tritoon, deck layout, etc.

My 20' Weeres is rated for a 50 to 90 HP and 10 passengers, etc. I don't remember the max weight...but it's on the plackard as well.

Travis

 

[lncoop]

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

On a barge it's usually by the helm, at least on every barge I've owned.