Compression low after rebuild?

[ackman]

After having a '95 FORCE 70hp powerhead rebuilt the compression readings are 100/105/105. I'm following all the suggested break-in procedures and only have 2.5 hrs of running time on the clock so far. Can I expect to see the compression readings climb over the next 7-8 hrs. before switching back to a 50:1 mixture? The "good" 2 cylinders were @ 124 psi previous to the rebuild, and I was expecting better with a "new" motor.

 

[WillyBWright]

Re: Compression low after rebuild?

Give the motor some time to break-in. Compression readings are fairly useless in the first 10 hours.

 

[Realgun]

Re: Compression low after rebuild?

The rings have not seated yet. Give it time 20 hours or more before first good reading.

 

[ackman]

Re: Compression low after rebuild?

Thanks for the replies. Performance and fuel use seem normal so far, as I'm up to 5 hrs. of ocean time now. Maybe 20-25 psi more won't help much. Anyway, I'm using a borrowed compression gauge and need to return it tomorrow so I won't "worry" until 15-20 hrs. have passed.