1994 SPX won’t fire

[shanejudge]

I recently purchased a 1994 Sea Doo SPX, bought it not running. Tore the carbs apart and rebuilt both, they were extremely dirty. Replaced the fuel lines, cleaned the fuel filter, drained the old fuel and put in fresh 40:1 for the first fire up. New plugs, has spark and fuel is flowing. It turns over, but won’t fire. Tried starting fluid over the carbs, tried gas down the plugs. Any ideas?

 

[NickCawks]

Did you rebuild the carbs using genuine mikuni parts?

Also don't use starting fluid on these motors. If anything just a little premix down the carbs.

If the fuel is truly flowing and you have spark than it would at least try to start. Given that it was running before hand it's very likely the carbs, but have you done a compression check?

 

[shanejudge]

We used genuine mikuni rebuild kits. The fuel does seem to be flowing and there is fuel spitting out of the cylinders with the plugs out. It does have lower compression, I believe it was 80psi on both

 

[mikidymac]

At 80psi that is your issue if it is correct. It will not typically start in the water at 120 psi.

Confirm with another compression gauge.

 

[shanejudge]

Thank you! We will definitely take a look at that. Sounds like a rebuild is in our near future

 

[themk]

If correct, 80PSI is junk and probably won't even start on the trailer.

Sometimes people will put a little bit of oil down the spark plug hole, and see if that temporarily raises compression. Either way it's rebuild time.