Thread: Compression test results
07-18-2011, 05:08 PM #1
Compression test results
Looking to see what results those that have checked the compression on the 215s & 255 Sea Doo engines as received when new.
I have seen several older posts that has cam timing adjustments, mainly looking for untouched stock RXPs and possibly the if there is a difference in the 27,28,29 & 51 cams.
08-09-2011, 04:47 PM #2
My compression( its not a new seadoo, but new rebuilt motor with pistons rings etc) straight up timming 150acrossed, lightly retarded 145 145 135, Full retard 140,140,130 thats with a 51 cam. I will be intalling a 29 cam and get back to ya with numbers
08-14-2011, 02:33 AM #3
Dave I put my 29 cam in tonight Me myself I never worry about compression on start for perfomance but I do care about all my cylinders being as close as than can in psi. if there low aslong as all are egual well i was 10 psi off one one cylinder i put my 29 cam in and at full retard i was 135 on all cyliners with a 51 cam full retard i was 140 140 and 130
08-14-2011, 10:14 AM #4
08-14-2011, 11:15 AM #5
Dave you have to remember that depending on how or what degree that cam was put in it could vary between skis...You can take two brand new skis and have completely different compression...now this isnt normal,BUT on my wifes 215 HP RXP the compression from the factory is 140 140 140,while others have checked theirs and have seen 135 135 135...so its hard to tell what the "correct" compression is....And yes there will be a difference between each cam as the 04-05 cams are different from the 06 and up...NOW i dont know for sure if there is any difference in 07 and up or not.....But different size cams will change your compression until you adjust it to the level you want..Also remember when playing with the different size cams to check your AFRs,they will change with the different cams...
08-14-2011, 11:36 AM #6
Yes, the numbers will vary even between skis of the same year. A Sea Doo tech told me that the '07 and newer skis should have 175psi on the compression check. I am yet to see or hear of one turning those numbers.
As long as we start with the locked cam/crank position on a properly assembled engine in good mechanical condition, the compression numbers is not something we should get all hung up on. The compression test is a good tool to verify that we have a engine in good condition but it can't be relied on as "I have great compression, everything is fine" tool.
08-14-2011, 01:01 PM #7
Picked up a easy Mph I had to take 2psi of fuel and its still richer at idle with full retard 8100 dialed stock ecu
08-14-2011, 01:29 PM #8
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