copression test

[lilpain]

is 120 psi on both cylinder,does it mean it needs a top end rebuild

 

[cli55er]

i vote yes

 

[lilpain]

Will it run in the water

 

[cli55er]

i have no idea. all i know is if my motor was at 120 i would rebuild.

 

[Phildoo]

I'm with 55er..

 

[lilpain]

Will it run in the water nice thanks for the support

 

[cli55er]

how should i know....i've never tried it, but hey give it a try i suppose. rebuild the top and it will run nice i'm sure. 120 is a tired motor.

 

[lilpain]

Will it run in the water nice thanks for the support. What I want to know if I can at least get one season on it I just bought it today.

 

[Dr Honda]

is 120 psi on both cylinder,does it mean it needs a top end rebuild

YES

Will it run in the water

PROBABLY NOT.

Will it run in the water nice thanks for the support. What I want to know if I can at least get one season on it I just bought it today.

HEY.... BE NICE TO THESE GUYS. THEY ARE TRYING TO HELP.


OK... here's the deal. I would first check your gauge to make sure it is right, and the little O-ring on the end is good. (I've seen people rip apart a good engine because of a bad seal on the gauge)

Second... assuming the gauge is right, and you did the test correctly... even if it will run in the water, it's going to be marginal, and it may be short lived. Right now, you can probably get away with a set of rings, a Gasket kit, and 2 hours labor... and you will have an engine that may run for a few more years. If you try to run a SeaDoo engine that is only showing 120 psi... the hot combustion gases will push past the rings, and over heat the piston crown and skirts. It will also push the oil off of the cyl walls, in turn, making the engine eat itself. When that happens... you will require a FULL rebuild that will cost you $500 if you can do your own work... or $1500 if you have a local shop to do it.


My semi-professional opinion is: If you run that engine, you probably won't get a season out of it, and it will cost you ALOT more later to fix. You are in a good position. You found a problem before it got out of control. Fix it now, and save money, and enjoy the summer.

 

[Dr Honda]

I guess I should add... when you see me quote a cyl pressure on this forum... that is for a SeaDoo Engine. If this same question was asked for a Polaris... you would be fine, since cyl pressure for a Polaris Domestic engine is only 125 psi on a fresh engine.

 

[lilpain]

Thank Dr Honda.

 

[cli55er]

I guess I should add... when you see me quote a cyl pressure on this forum... that is for a SeaDoo Engine. If this same question was asked for a Polaris... you would be fine, since cyl pressure for a Polaris Domestic engine is only 125 psi on a fresh engine.

where did he mention it was a polaris? i assumed he meant seadoo.

 

[Dr Honda]

where did he mention it was a polaris? i assumed he meant seadoo.

He didn't... but I don't want people taking the info of "150 PSI" and thinking that all engines need that kind of pressure. (just some extra info)

 

[BMANN06]

Doc those answers are very true ... and somewhat entertaining AFWIW we (speak for most of us on this site) consider your opinion "professional" :cheers:

 

[Dr Honda]

Doc those answers are very true ... and somewhat entertaining AFWIW we (speak for most of us on this site) consider your opinion "professional" :cheers:

Thanks for the pat on the back. It makes me feel good, knowing I'm liked.

The reason I call myself a "Semi-Professional" is because I don't have any formal training in watercraft. My shop is biased off of motorcycles, but I seem to work on more PWC in the spring and fall... than I do with bikes.


The shop: