Compression

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What is an Acceptable compression range for a 1995 sea-doo 650 gtx with a 1mm over bore? I'm measuring 125psi on both cylinders
 
150-155psi is perfect, below 135psi is time for a rebuild. If the engine runs fine in the water, then you might want to try a different gauge.
 
If it starts well, runs well, and the plugs look like a light ale, ( after running, and not after a plug chop)...then 02 is right, try a different gauge.
 
It’s probably the gauge.
I just finished putting the motor back together with new crankshaft all new gaskets, new top end, cylinders were recently bored etc.
 
I'm waiting on a new gauge myself, my boat runs ok in the water but the starboard has always had a tendency to stall at low revs. I think the last compression tests I did with my old junk gauge were barely 100 for that motor and 120 or so for the other motor so I suspect starboard needs work anyway.
 
That’s correct you must have a RIK rings they have markings on the bottom of top ring
Maybe try another gauge
 
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I'm waiting on a new gauge myself, my boat runs ok in the water but the starboard has always had a tendency to stall at low revs. I think the last compression tests I did with my old junk gauge were barely 100 for that motor and 120 or so for the other motor so I suspect starboard needs work anyway.
A new or quality gauge can make all the difference. Both of my motors have 145-150 with a vintage Peerless compression tester, what a difference!
 
I have only seen rings with the marks facing up. Used a lot of RIK (WSM) ones over the years.

Typically if you have the tapered ring upside down or in the wrong groove they will not fit into the piston groove correctly.
 
I have only seen rings with the marks facing up. Used a lot of RIK (WSM) ones over the years.

Typically if you have the tapered ring upside down or in the wrong groove they will not fit into the piston groove correctly.

I have wsm rings installed and I have a set of sbt unopened and wsm markings are on bottom of top ring and on sbt rings the markings are on top of top ring. I’m pretty confident the rings are in properly. I’ll try a better gauge and make sure I crank until it stops building and go from there. Thank you everyone for the help.
 
I have wsm rings installed and I have a set of sbt unopened and wsm markings are on bottom of top ring and on sbt rings the markings are on top of top ring. I’m pretty confident the rings are in properly. I’ll try a better gauge and make sure I crank until it stops building and go from there. Thank you everyone for the help.

I believe you, just can't say I have seen that. Let's see what the new compression test says.
 
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