97 GTI Power Loss

[spydraver]

I’ve got a 97 GTI. New to me. I’ve replaced the fuel lines, cleaned the fuel selector switch, new plugs, and rebuilt the carb. Yesterday it ran great WOT all afternoon no issues. Today after about 20 minutes of riding I notice top speed is dropping off. Start heading back and it’s getting slower and slower. Eventually it dies. Restarts immediately and it went fast again for about a minute then same thing happens. I notice what I think is a buzzing or noise from the area under the front storage where the MPEM is located. Rinse and repeat a millions times to get back to dock.
Looking for ideas where to begin diagnosing this problem.
Thanks

 

[Saludadoo]

Did you ever pull the carbs off?
There is a small filter inside the carb.

 

[spydraver]

Yes I've pulled the carb cleaned and rebuilt it last week.

 

[POPPS]

What is the motor?

 

[spydraver]

It’s the 717. Going to pull plugs, compression check, check battery, check rectifier, grounds, connections. Will report back my findings once I get the ski back in the garage.

 

[POPPS]

Check your connections up front,,,male and female.,there should not be any buzzing sounds,,,unless you are in a garden.

 

[mikidymac]

First off you can't clean the fuel selectors, they need to be replaced.

Second did you actually rebuild the carbs with all new Genuine Mikuni parts?

 

[spydraver]

The engine is a 717
I removed the fuel selector and verified it wasnt clogged or full of crap, blew it out etc etc.
Yes I fully rebuilt the carb with genuine mikuni parts. Did not replace the needle and seat.
So far I’ve checked the compression, both cylinders at 135 psI. Replaced and gapped plugs. Removed battery Ground and cleaned all connections. Replaced the rectifier (really thought that was the problem). Checked the voltage coming into the battery while at high rpm about 12.9 V. I disconnected the battery and charged it with an automatic charger until I noticed the battery getting very hot, but the charger still thought it needed more. So once the battery cooled down I took it to the auto store and had it tested. They said it was fine.
Today I took it back out today and it ran great for about an hour then top end started dropping off again. I would kill the motor and restart. Same thing. Take off at full speed for a few minutes and drop off again. After todays run I checked the plugs and they were very wet looking.
My shop manual says the HS screw should be at 0, Seadoo Source says 1 1/2. It's currently set at 1 1/2.
back to the drawing board

 

[mikidymac]

Replace that fuel selector and get new needles and seats.

 

[Legacy37]

I recently was having issues with my 97 gti. Rebuilt the carb....kit did not come with needle and seat, it did not fix the issue. Got mikuni needle and seat, it fixed it.