97 spx

[JCS55]

Having issues with no power low to mid range, ski seems to run fine on WOT until ski is warmed up, then it is a noisy turd bobbing down the lake. I have cleaned RAVE valves, checked exhaust pipes for plugging, cleaned carbs, and scratched my head a lot. Wondering how coils fail, many ways? Slowly? Suddenly? Hate electrical, so any input is appreciated, thanks

 

[JCS55]

Having issues with no power low to mid range, ski seems to run fine on WOT until ski is warmed up, then it is a noisy turd bobbing down the lake. I have cleaned RAVE valves, checked exhaust pipes for plugging, cleaned carbs, and scratched my head a lot. Wondering how coils fail, many ways? Slowly? Suddenly? Hate electrical, so any input is appreciated, thanks

Bump, anyone?

 

[Pwnage1337]

Did you check the voltage regulator/rectifier? They can cause weird issues with AC voltage getting into the DC systems that run the ski - makes them do weird things with spark, won't rev up past certain RPM. I have seen them be intermittent where the ski will run OK for 4 minutes then totally fall on its face and not even get off idle.

At first I would say check the carbs and rebuild them. Did you check pop-off when you had them apart?

 

[tjones823]

Check your carbon seal and bellow could of slipped on drive shaft.. very common with the older models.. just had same issue and rectifiers go bad commonly on older seadoos to

 

[JCS55]

Did you check the voltage regulator/rectifier? They can cause weird issues with AC voltage getting into the DC systems that run the ski - makes them do weird things with spark, won't rev up past certain RPM. I have seen them be intermittent where the ski will run OK for 4 minutes then totally fall on its face and not even get off idle.

At first I would say check the carbs and rebuild them. Did you check pop-off when you had them apart?

Thanks. Rebuilt the carbs following the sticky to the T, pop off is 38 and 36 psi after cleaning.

 

[Ckrawiec]

According to the service manual.....depending on what size your carb valve seat diameter is: Your pop-off pressure should be (see the following) assuming you have the proper 80 gram spring installed in the carbs...

1.2mm -> 48 +/- 12 psi
1.5 mm -> 33 +/- 10 psi
2.0 mm -> 21 +/- 7 psi

So, judging by your pop-off settings of 38 & 36 psi....we would assume you have the 1.5 mm valve seat diameters

 

[JCS55]

According to the service manual.....depending on what size your carb valve seat diameter is: Your pop-off pressure should be (see the following) assuming you have the proper 80 gram spring installed in the carbs...

1.2mm -> 48 +/- 12 psi
1.5 mm -> 33 +/- 10 psi
2.0 mm -> 21 +/- 7 psi

So, judging by your pop-off settings of 38 & 36 psi....we would assume you have the 1.5 mm valve seat diameters

Thanks. Yes for spring and seat. The ski ran awesome after rebuild and didn't find anything when I cleaned them. Leaning towards the coil, if I am measuring it correctly the primary is failing the test.

 

[JCS55]

Check your carbon seal and bellow could of slipped on drive shaft.. very common with the older models.. just had same issue and rectifiers go bad commonly on older seadoos to

Wasn't the coil. How do you check the carbon seal? Still learning this game of jetski. The day that all this started happening I had given the grease zerk on drive shaft a couple of pumps and noticed that there was some movement of the boot towards the back of ski...

 

[mikidymac]

Basically run it on the trailer and in the water and watch the seal and see if it is leaking water.
Also how does the boot and seal look?

Usually on these it is a fuel system problem. You can't just "clean" the carbs and selector. Carbs need to be correctly rebuilt using all new Genuine Mikuni parts and fuel selector replaced.

 

[JCS55]

Basically run it on the trailer and in the water and watch the seal and see if it is leaking water.
Also how does the boot and seal look?

Usually on these it is a fuel system problem. You can't just "clean" the carbs and selector. Carbs need to be correctly rebuilt using all new Genuine Mikuni parts and fuel selector replaced.

Boot and seal look good, boot is pliable and no cracks. About 10 hours on ski since I did the fuel lines and carb rebuild following your post to the letter, used the post for cleaning as well. New aftermarket fuel selector this spring. It seems like it something simple, but just don't know what. Water fuel separator? Has good compression, 140/143, just don't know why there is a lack of acceleration and when it gets warmed up the top end goes away as well...

 

[JCS55]

Just ran in water on trailer, no leaking at carbon seal or boot. However, I noticed that the pressure regulator on the muffler was leaking water, could this be my culprit?

 

[mikidymac]

The leaking regulator will cause a loss of a few hundred rpm on top end and overheating of the exhaust.

 

[JCS55]

Update. Wish I had good news to post, but am still having trouble. Fixed regulator and saw an increase on top end, but when let off on throttle i am back to bogging. I have put in a new oring on water fuel separator and by passed the fuel selector. I ran the reserve line to the separator. Still having the same issues. When I cleaned the carbs I did not remove the seat only the needle, would that make a difference? Still stumped and the season is almost over...

 

[mikidymac]

Yes you should be replacing the needles and seats together with new genuine Mikuni parts.

 

[JCS55]

Yes you should be replacing the needles and seats together with new genuine Mikuni parts.

I did replace needle and seat, when I rebuilt carbs with genuine Mikuni parts, have about 10 hrs on ski since rebuild, but I did not remove seat when I cleaned them recently, just wondering if that could be an oversight on my part when I cleaned them and is causing my dilemma

 

[tobytd]

Doesn’t look to me that the carbon seal is installed in the rubber bellows correctly.

 

[POPPS]

The carbon ring looks mashed!

 

[JCS55]

Doesn’t look to me that the carbon seal is installed in the rubber bellows correctly.

Not my pic

 

[JCS55]

The carbon ring looks mashed!

Not my pic