90 SP Fires but won't run

[tregger]

Hello all,

My 90 Waverunner has a new friend- I purchased a 90 SP that needed a starter.

I replaced the starter and exhaust gaskets. It will turn over, occasionally start, run poorly for a few seconds and die. I have checked the fuel pump, and it is working. I have not checked compression. Previous owner seems to be very honest, and claims that it was running well before the starter died.

I will report back as I complete further troubleshooting.

Any ideas?

 

[POPPS]

The fuel pump is integrated into the fuel pump,,,it does not have an external fuel pump. Does it start right away if you pour some premix into the cylinders?,,,If yes,,,you have fuel delivery issues,,,
Do a compression check as well.,,put in new plugs,,,

 

[tregger]

Mine has a fuel pump mounted to a plastic bracket near the fuel filter. I’ll try some premix in the cyl, compression test, new plugs today and report back

 

[tregger]

I installed new plugs. Checked compression, both cylinders were 90ish PSI.

It runs with full choke and partial throttle. Fired on mixed gas.

Carb rebuild time?

 

[mikidymac]

If that compression is accurate it is way too low and will never run on the water.

 

[tregger]

Gotcha, what compression numbers should I see from the Yellow 587?

Rebuild time I guess.

 

[mikidymac]

150 psi. At 120 they are done and need a rebuild.

I would double check it with a different compression gauge before tearing it apart.

 

[tregger]

sounds like a good plan. I thought that 90 sounded low. Tested my waverunner (FWIW) and got 90 as well. The waverunner is a very different animal but has never had an issue starting and running on the water. This gauge might be garbage.

 

[tregger]

Tested the seadoo with a good compression tester- 130/135 psi.