Thread: Compression Issue With 02 GPR
01-02-2009, 10:13 AM #1
Compression Issue With 02 GPR
I need some clarification on a 02 GPR I thinking about buying. I did a compression test and got a reading on approximately 91 psi across all three cylinders. I did some research and it seems to me that the standard cylinder compression should be around 122-125 psi range. The seller did say that the ski will not get above 45 mph in choppy water. The craft has been neglected so it does have "at least" one year old fuel and oil and more than likely was never properly winterized. My question is, is the 91 psi being so consistent normal or is it user error with me taking the readings. I thought it was pretty trivial to do it, get a good seal select the proper attachment for the spark plug hole and crank the motor a few times. It's just weird to me that if the cylinders are bad why would they be so equally bad. The compression tester is brand new btw.
Thanks for the help.
01-02-2009, 10:16 AM #2
welcome to the forum !
did you do the compression check with the throttle wide open? also did you remove 1 plug at a time per compression reading?
the consistent numbers is good. For a stock motor, just a hair bit on the low side [not to worry], but could be variations in gauge accuracy and method of testing, and battery strength.
01-02-2009, 10:25 AM #3
Thanks for the link, sorry I did do a search but must have missed that link. After reading your write up I think it could be the battery and perhaps the cold weather (it was 34 F when I did the test). Also yes I did one plug at a time, and no not at WOT. The seller jumped the battery both times before I got there so that battery is fried I thought it was fine because it started right up no problem. I will look into it some more.
01-02-2009, 10:27 AM #4
As for the speed, I would also check to see if the powervalves are opening properly.
01-02-2009, 10:38 AM #5
I do hear the pv servo do its cycle when power is shut off. Is there another way to check the pv's ? Thats another thing worries me 124 hours with no wave eater clips .
I will be putting it in the water to see if its a cavitation issue thats giving it the speed loss. Thats a easy fix though.
01-02-2009, 10:52 AM #6
I think your servo motor is fine.
There are some bullet-proofing you need to do.
- Wave-eater clips
- Pump tunnel Reinforcement
- Seal the pump shoe
- Replace the Stock intake grate with an aftermarket grate
I would also check the impeller wear ring clearance or speed loss too.
Several things can cause this. A pumps shoes that is hanging down can cause a speed loss.
01-11-2009, 11:12 AM #7
I bought the ski after doing another compression check. All the cylinders tested in the 121 range. As for the speed loss, I took a friend of mine that has a 00 GPR and right away he noticed the cat sensor was attached. We tore off the exhaust, sure enough, a plugged up cat that was freely moving around in its housing; you cant even see through the thing. All that's left now is to do some of the bullet proofing mods you mentioned and she will be good to go for some February cold weather riding.
Thanks for the advise RX951
01-11-2009, 11:17 AM #8
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