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Old 11-25-2009, 09:17 AM
Bigshrimpin Bigshrimpin is offline
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Join Date: Dec 2002
Location: Onset, MA
Posts: 2,712
Default Re: Compression Question????

Quote:
Quote:
Yea...Unfortunately

80 psi: note verticle grooves:



Pull piston: note stuck ring and more vert damage


120 psi: Cy; deglazed with hone 90% of vert grooves gone, cross hatch re-established, comp back up to 120, motor is happy again. Thes pix were about 3/4 thru...it looked a bit better when cleaned. I put in a new cly and ring kit. Rod and needle bearings too.





It dosnt make me feel good that I had to perform surgery but like Tim has said these motors are tough and basic and it didnt seem to mind the work. My motor was a nice clean motor that I aquired for cheap money before I gooned it up. I hope to get a few seaons from it still.
Now the class has my attention.
When I talked to Art @BRP tech he said that these motors left the factory at spec between 90 and 130 comp. I thought that to be strange. He said that as long as they were even that was proper spec for release.Said they matched the piston/ ring combos. My motor is 87-92 and turns 5200 light Bimini up. Should I be concerned? Anyone local have a scope?

Decarbed 30 hrs ago w/ Engine tuner thru the Schrader and then pony tank Seafoam 3 cycles. `til the forest fire smoke stopped. 930 hrs now."Pros" all say don`t worry, but I am. Always.
Thx,
GFS

Sandy - your guy is right. I've seen two 1994 200 and a 1995 225 that had 100 - 105 psi in all 6 and perfect cylinder walls. The point were I'd be concerned if you had a motor with 120 psi like hermit's 2000 225 and had one cylinder drop to 80psi from 120. I mess around with merc's so I can't tell you exactly what OMC models were higher compression. If all yours are the same and the motor runs well . . . I wouldn't give this another thought.
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