Thread: SHO Compression
07-22-2009, 07:42 PM #1
Has anyone done a compression test on their SHO/FZ? I had an overheat over the weekend & when I checked it I'm seeing 140, 135, 135, 130 psi in the water @ full throttle. I checked the svc manual & I saw the comp. should be 87psi.
07-22-2009, 07:55 PM #2
07-22-2009, 07:55 PM #3
11-12-2009, 08:23 PM #4
how did you check compression on the water at full throttle????
I thought the only way to do it was have the ski up on the trailer with all the spark plugs out??
11-12-2009, 08:40 PM #5
11-12-2009, 11:10 PM #6
11-13-2009, 11:33 AM #7
I just looked at the svc manual & it says to remove all the plugs before testing. I've always heard you should remove one plug at a time. Not sure what the proper method is??? There was also no mention in the manual of holding the throttle open, which is how I checked mine. Is this why I was seeing a much higher compression reading than the 87psi spec from the manual?
11-13-2009, 10:15 PM #8
11-14-2009, 09:57 AM #9
so hold the throttle open when cranking with all plugs out is the proper way?
11-14-2009, 10:33 AM #10
- Join Date
- Apr 2008
This might sound really dumb and be way off.... But wouldn't your compression reading change depending on what supercharger wheel you are running?
I'm not sure about the first part, but I do know that you should pull all the plugs, hold the throttle wide open and turn the motor over using the starter to check the compression of each cylinder one at a time.
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