94 seadoo xp has spark but wont start.

[Nicks5.2]

This sounds identical to my problem I just asked about in another post. This was my post:

Can anyone tell me why it won't start? It cranks, sparks, ~120psi on both cyl, all fuel lines clear, and I disassembled the carbs to clean/inspect. They looked great. The plugs show nothin but oil. Why isn't the gas being drawn into the motor?


It seems like it's getting some gas trough but enough to even idle.

 

[holorinhal]

Ok I rebuilt the carbs and replaced all fuel lines. Reinstalled the carbs and tried cranking. It is still doing the exact same thing. I turns over fine. I can here the engine trying to start butbut just wont start up and run. Where do I go from here?
Read in the manual that the spark gap should be .020, is that correct.
When i pull off the return line it has alot of fuel in it ,should that be the case?
What should the spark look like on the plug? What else should i try?
When turning over I can here it fire like it wants to start but it just wont. Sometimes it will fire of for a couple revolutions and just die.

 

[holorinhal]

Ok I gues its bad news!

Well after messing with it for a while i decided to recheck the compression again. I tested both cilynders and oh no, only 120-125 in both cilynders. I squirted some oil in the cilinders and retested and it jumped up to 150. So I guess it is rebuild time? I am just curious as to why they tested at 140-145 the first tme before the carb rebuild? Now should it be a total rebuild or top end rebuild?

 

[Bills86e]

Remove the RV cover and check for a stripped RV gear. To do that remove airbox & arrestor plate on carbs to get to the four 13mm bolts. Do the hardest to reach bolt 1st, the bottom right. Remove the cover & carbs as a unit.

Next remove the grey drive cover at rear of engine and hand turn the PTO flywheel left & right, watch the RV. It may help to put a zip-tie on the splined shaft just so the RV plate doesn't come off.

 

[holorinhal]

Remove the RV cover and check for a stripped RV gear. To do that remove airbox & arrestor plate on carbs to get to the four 13mm bolts. Do the hardest to reach bolt 1st, the bottom right. Remove the cover & carbs as a unit.

Next remove the grey drive cover at rear of engine and hand turn the PTO flywheel left & right, watch the RV. It may help to put a zip-tie on the splined shaft just so the RV plate doesn't come off.

I have the air box of allready buthe flame arrester plate and screen are onM So remove the carbs again? How do I see the rv? Do I need to remove the intaake manifold?

 

[Bills86e]

Yes, carbs intake flange cover all come off the engine as a unit.
http://partsfinder.onlinemicrofiche.com/seadooforums/Seadoo_oem/Seadoo_PWC.asp?Type=13&A=20&B=4

 

[holorinhal]

Ok so i took off the rotary valve cover and I turned the pto and the rotary valve spline shaft does not turn at all. I can hear the gears inside just skipping past each other.
I found a small piece of metal on the surface behind the thin rv plate and the face of the rv cover is all grooved. the grooves are not normal are they? here is a pic.
What causes the rv gear to strip? would the rv not turning cause a low compression reading? So where do I go from here?

 

[Bills86e]

Options are to do a total rebuild or replace. A worn RV cover is cause of hard starting and premature death of starters.

Bills86e

 

[holorinhal]

Wha needs to be done to the cover? should it be machined ,or does it need to be replaced?

 

[Bills86e]

I suggest an overhaul of the engine......again. You could go after each individually but thats costly. I don't recommend Replaceing the shaft
& gear and maching the cover. Brass bits & shards are in the crankcase. Likely the shaft is bent and exceeds the .002 runout spec. More likely than not, the steel gear on the crank was moved rearward and 99% of the time will chew up a brand new gear. I believe the crank and
seals are worn out, Compression was stated is low as well. If you broke it down to a basic core shortblock, it would be your most cost fix.
Doing it yourself you will be snapping bolts off and alot of labor you may not be able to do and alot of down-time.

Bills86e