GTS Wont rev to Full Speed???

[victorgallas]

Hey,

I have tried doing some search on this and wasn't able to find much.
I have a 2001 GTS with the Rotax engine and a single carb.
A month ago I took it out after sitting for about a month and in order to have the jet ski crank over I had to use a battery charger to help boost the engine. I know you are not supposed to boost it but I boosted the jet ski using a battery charger on which you can control the current and voltage levels. When I took the jet ski to the water it started but it wouldn't rev past half of its engine speed range. Essentially it never went past LO speed. If you held it at wide open throttle the engine just sounded really loud and bogged down.

So after this failed attempt, I took the carb apart completely and cleaned everything and reassembly it. I also put a brand new battery since I was able to determine that the previous one had failed. This past weekend I put it on the water and again the same problem, it wont rev to full speed and sounds bogged down loud. I then took the seat cover off and tried to running the jet sky while feeling for anything in there. What surprised me was that on the air inlet box, instead of feeling a constant air flowing into the box, I could feel a good amount of air flowing OUT of the box, as if it was being pumped out trough the carb???

My question is: If a jet Ski has been boosted, will the booster damage the electric control unit?
If so, what is the damage? Will the control unit simply stop working altogether or will it not do the ignition advance necessary to rev the engine to its full speed?
Is there something else, based on my description that I am missing out?

I also wanted to ask about the engine temperature sensor, if that sensor fails and the control unit thinks that the engine is over heating, will it limit the engine RPM as a safety default?

Thanks and please feel free to ask for more information.

 

[Dr Honda]

My question is: If a jet Ski has been boosted, will the booster damage the electric control unit?

Yes it can. a charger will give a voltage spike when a sudden load is applied. The damage can be a roasted MPEM. BUT, since yours is starting, I would say that it's fine.

I also wanted to ask about the engine temperature sensor, if that sensor fails and the control unit thinks that the engine is over heating, will it limit the engine RPM as a safety default?

No... your ski will just sound the warning buzzer, if it overheats.

You are describing a fuel related problem. Do you have gray fuel lines? If you do... the need changed, and the entire system cleaned. Or, you could have an air leak somewhere. (like a bad O-ring in the filter)

Finally, check your compression.

 

[victorgallas]

yeah I have replaced some of the gray lines, but not all of them, so I will go ahead and replace the entire system.
I wasnt thinking too much on the fuel system because I had just cleaned the carb and I didnt find any gunk in the filter inside the carb. however it wouldnt surprise me if there is some major gunk build up on the filter screens on the pickup on the fuel tank or even the valve.

I will check the whole system.
I didn't think of fuel issue since I normally think that lack of fuel would make the engine sputter when at wide open throttle, but I don't get any sputtering, just it doesn't go at all.

Ill did into the fuel system... See what I can find.

Thanks a bunch for the input.

 

[Mr Africa]

Hi
See if you can test your Mpem. It could also be going into safe mode.
that would limit the rev range. Does it idle smooth and at about 13 to 1400 rpm. Maybe with the boost it could have damaged something.
I had the same fault with mine going into safe mode and it took me a while to figure it out. Hope you come right.

Cheers

 

[simplewon]

How do you get it out of safe mode? Reset the computer on a 97 speedster?

 

[Dr Honda]

How do you get it out of safe mode? Reset the computer on a 97 speedster?

You should start your own thread... and please don't bring threads "Back from the dead". The last post was 7 months old. Also... you are asking a boat question in the PWC section.


Anyway... a 97 speedster doesn't have a "Safe Mode"... so I'm not sure what you are asking.

 

[simplewon]

After obtaining the manual, the computer has a rev limiter while in neutral.