'96 Speedster Power Issues - Rev Limiter?

[parkericharda]

I have had an issue with my port engine this year (2012). When I first start the boat up, seems to run well. It revs up to get me on a plane, which is normal of course. After a while though, I begin to loose some power. Throttle can be all the way up, but still have issues with it. Then after a while, I might bring throttles down, and idle for a bit, and then it can magically be fine for a while. This happens on and off.

1. Does this boat have two rev limiters, or is it one combined? In other words, is it possilbe for one engine to have an issue with the RL but the other engine fine, or would they both have issues?

2. Would a dirty carbeurator cause such a problem... where it's fine for a while, then have low power?

Hope you can help!
Thanks!

------------------------
Richard P.
1996 Sea Doo Speedster
Twin 85hp Rotax Engines

 

[Shuntavi]

It could be fuel delivery. It could be running out of fuel while you have it wide open. Could be maybe overheating. Have you done a compression check on the suspect motor? Don't think the carbs are dirty but it may be the in the fuel suction.

 

[parkericharda]

Fuel Delivery

It could be fuel delivery. It could be running out of fuel while you have it wide open. Could be maybe overheating. Have you done a compression check on the suspect motor? Don't think the carbs are dirty but it may be the in the fuel suction.

Fuel... hadn't thought of that. How would one check that? Is compression check something I can do myself? I wouldn't say I'm an engine pro

 

[Shuntavi]

You can check compression yourself easily. You need a tester which you can get at your local Auto parts store. Just make sure it has the attachment for you spark plug hole so take a plug with you when you go get one. As far as the fuel problem there are other people on here that have checked it. Dr. Honda and brock 1 would know. Fuel lines could be a problem on these older machines. Make sure you don't have the old grey original lines.

 

[parkericharda]

Sea Foam

What about Sea Foam? Would that help with anything?

 

[CaptSteve]

DO NOT RUN SEAFOAM or any carb cleaner. These are two stroke engines and if you add a carb cleaner it can wash the oil off the cylinder walls. I know Seafoam says it can be used on two stroke engines, but IMHA I would not do it. Others may disagree, but that is my opinion.

As others have said, check your fuel delivery system. If you have the Gray Tempo fuel lines, replace them now. The old gray lines deteriorate from the alcohol in the gas now. Then take the carbs off and clean all the little passages inside, remove the fuel selector switch and clean the insides, change the fuel filter, check the tank for gunk on the bottom.

If your fuel lines have been replaced, look for an air leak in one of the fuel lines, check the fuel filter, clean the fuel selector switch, and check the fuel pump. If this does not fix it, then clean the carbs and check the pop-off pressure.

It also never hurts to do a compression check on the engines. They should read around 150psi in both cylinders within a few psi.

 

[parkericharda]

fuel filter

I will check the fuel filters... I think they are right on top, right? One for each engine?

 

[parkericharda]

Took out after one month, runs great for 20 minutes.

Today I took the boat out for the first time in one month. It ran so well (for a while). Both engines had maximum power I've ever had... peaked RPM around 7k. After about 15-20 minutes though, the Port engine started to get sluggish again. I can't imagine it's a fuel delivery issue if it runs great for 20 minutes. It's almost like it starts after it warms up. Any thoughts?

 

[Dr Honda]

What about Sea Foam? Would that help with anything?

As above... never put a solvent in the fuel of a 2-stroke !!!!



OK... to answer your question... yo only have one rev-limiter... but it watches the engines individually. BUT... a rev-limiter doesn't just drop the power. It a very distinctive ignition miss.

Continuing to run a 2-stroke that is "Sagging" in power, is just asking to kill the engine. When they go lean, they run hot. Also... they don't properly transport the oil into the engine.

Your problem is fuel related. It could be a clogged filter... dirty carbs... or an air leak in the fuel system on that side.

BUT... depending on how long you've been running it this way... your problems may be deeper. I would check the compression before worrying about anything else.

 

[parkericharda]

no issues at start-up for 20 min

This leads me to a question... help me understand how it can be justfine for 20 minutes when starting, and then start to be "lean"? If it is a fuel issue, wouldn't it have these power issues all the time? Thanks for helping me understand it.

Also, a bad spark plug wire would be causing this all the time as well, right? I can see I could spend a butt-load just to find the issue, then pay to repair it. Ca ching. :O)

 

[parkericharda]

problem fixed

Turns out that had to have the two carbs rebuilt ($$$) to fix the problem. I guess when they got warmed up, that's when the issues started. They are looking at something else now too, because it's having issues getting up to speed initally... not sure what they mean, but hopefully when I get it back, it will be like new. Thanks for your advice everyone.

 

[parkericharda]

Now they are telling me they think the wear ring is worn on the Port engine. I find this hard to believe becuase they say once it gets up to speed it runs great, and I've not had any issues with it lately, other than the carb issues.

1. How long in average situations should a wear ring last? I replaced one not terribly long ago.
2. Would a worn wear ring cause it to be slow to get up to speed, but then take-off and be consistent at 7k RPM without any hiccups? Or if it's worn, should it have issues the whole time, whether going slow or fast?

 

[95seadooser]

having the same problem
motor runs like a raped ape for 10 min then loses rpm to 4500

also if you turn hard right it will gain its rpm back for 30 seconds