No acceleration, idles fine

[EricSki8]

Hi! Thought to post to see if anyone had any thoughts. I have a 97 sea-doo gti 2-stroke pwc that starts right up, idles good, but does not accelerate. The pitch of the sound changes when I hit the throttle like it wants to rev up, but it does not. I was just idling on the water when I last took it out so had to put it back on the trailer and tow it back.

The grey fuel lines were replaced by previous owner (time frame unknown). Just rebuilt the single carb on it. Put new spark plugs in. Put in new fuel filter. Emptied the gas tank (as much as I could pump out) and put in fresh 93 octane premium gas in today. Pumped out old oil and put in XPS stuff. Put in new and fully charged battery (AGM) that I had put in a trickle charger for at least 36 hours. The battery is reading above 12 volts on the meter. When I start it to idle briefly (under 10 secs), I can see the impeller moving without any obstruction. I checked in intake underneath the pwc and with a flashlight could not see anything wrapped around the shaft to the impeller or obstructing the intake area. I did a compression test and both read slightly on the lower side of 125-130 for both MAG and PTO cylinders, but nothing in my mind for concern when it comes to accelerating and revving the engine with full throttle.

So I am a little confused as to what could be causing it to not accelerate or rev up when I open the throttle. Any ideas? Thanks! Eric

 

[Mraw]

Is the engine revving up but not moving? Does it feel like a slipping clutch in a car?

 

[NickCawks]

Those compressions are a bit low. Are you using a reliable compression gauge (not from harbor freight)?

Whenever I hear symptoms like this the first thing I think is low compression. The second is carb issues.

 

[EricSki8]

Is the engine revving up but not moving? Does it feel like a slipping clutch in a car?

Unfortunately no revving. It was able to rev up just fine about 2 weeks ago while on the trailer. Unfortunately it did not want to rev ever since I tried to take it out on the water. It doesn’t feel like the clutch is slipping cause of the no revving.

 

[EricSki8]

Those compressions are a bit low. Are you using a reliable compression gauge (not from harbor freight)?

Whenever I hear symptoms like this the first thing I think is low compression. The second is carb issues.

I bought an Innova compression gauge (around 30 bucks) to test. I was thinking I would recheck the carbs. Plus I plan to replace both of the carburetor gaskets (1 that meets the air box/fire suppression and 1 that connects to what I think is the bottom end of the engine). Not enough air getting to the carbs or not enough fuel getting there? I’m open to all suggestions and things to look for.

 

[mikidymac]

Compression is low.

Did you use Genuine Mikuni carb kits and needle and seat?

 

[EricSki8]

Yup since I have seen that being brought up in other threads.

 

[POPPS]

Is it charging?

 

[EricSki8]

Is it charging?

I haven’t checked the stator, but the battery is new and fully charged. Would this affect acceleration with a bad stator?

 

[POPPS]

A failing stator can cause rev'ing issues

 

[EricSki8]

Replaced stator… pain in the ass taking off the flywheel. Same issue, no revving or acceleration.

 

[POPPS]

I did not intend for you to replace the stator,,,but to test it out,,,when you start
the ski...your initial voltage should be at least 12.5 V

 

[Lothsahn]

Eric,

Does it have an RPM gauge? When you give it gas on the water, does the RPMs increase?

You have two possibilities:. It won't rev or it is revving but not going.

The first is engine or electrical, the second is pump related. Really need to understand which of the two you're having.

You said the pitch changes but it doesn't rev, which doesn't make much sense to me... Usually the pitch is related to the RPMs.

I'm just guessing but try unplugging the red wire from the voltage regulator and see if that resolves the problem. If so, you need a new voltage regulator.