Compression numbers for 951?

[scrisp]

Looking at a 99 GSX Ltd, and the owner says that the compression numbers are at 120psi each. Is that low/normal for a 951 motor?

Most of the others that I've seen say that by the time they get to 120, it needs a top end rebuild, but I thought that I read somewhere on a thread that the 951 is lower.

 

[nammer]

i've read from other members that 951 motors have 135 normal versus 150ish for others, as far as what needs a rebuild, i'm not sure

 

[Strizzo]

120 is "service engine soon" territory, but is serviceable. problem is that it is not recommended to only do a top end on them due to the crank already being overstressed.

 

[Piper Mike]

Mine is 120 both sides and has only 45hrs on it.

 

[SabrToothSqrl]

Acording to the actual sea-doo service manual, compression readings on the 951 are useless for a 'performance' reading.

They only tell you if the engine is DOA. example: 120 on front and 10 on the rear... would be dead.

water testing is the only real way. a brand new 951 with a brand new OEM impeller / wear ring / etc. should run 7,000 RPM WOT or damn close to.

6800-6900 are acceptable.

6500 and you have issues

6200 and you have major issues.

jet pumps develop thrust exponentially, those last 1000 RPM means the difference between 45 MPH and 55 MPH... (not quite, but you get the idea)...

the 99 GSX LTD is a very fun, fairly easy to work on ski. Replace the grey fuel lines, clean the carbs and fuel filters, raves, change jet pump oil, and make sure the electric bilge pump and scuppers work, and go ride.

Here's my restore of a 99 GSX LTD:

https://www.facebook.com/media/set/?set=a.4094673318041.2163806.1019051350&type=1

I got a new seat and bilge pump installed as well, just no photos yet. 2nd round of buffing tonight or Saturday... plan to do my 99 GTX LTD hull as well, that's all sorts of faded.

 

[summer]

I have read from reliable sources that a stock 951 pushes 130psi at sea level.