Mike Faulhaber wrote:
> Have a 1988 sea ray with i/o 130 Mercruiser. Three
times since 1988 the
> engine developed low compression in one or more of the cylinders. The first
> time the boat was 1 1/2yrs. old. The oil is changed twice a season and the
> boat is never beaten, usually running at cruising speed @2900 rpm. My
> question is if others are having this sort of problem and what they did to
> eliminate it, or did I get a lemon.
Assuming you have had the same motor rebuilt each
time.....Find a shop
with an ignition scope or analyzer. The distributor could cause the
dwell and timing to be different for each cylinder, causing advanced
timing on one or more cylinders. A regular dwell meter only gives the
average dwell, and not the dwell for each cylinder. Timing the motor
properly to cylinder one with a dwell of 31 degrees, with the dwell on
cylinder #3 at , lets say, 21 degrees, will advance the timing on
cylinder #3 enough to cause pre-ignition, piston and or head gasket
failure. [ I know a guy who had his 4 cylinder rebuilt 5 times in 5
years, before this was caught.