Rust on spark plugs, Compression OK, is motor bad?

[Chris1956]

I looked at an '87-88 Black Max 150 (Serial Number began with 0B). The lower had some barnacles and the LU nuts and bolts were corroded. All cylinders had 110-115PSI, but cylinders 2 and 6 had some rust on the base of the gapless plugs. The LU grease was clear and green, and the motor was in pretty good shape except the tilt tube was not used for the steering cable and was heavily rusted.
Do you think water is getting into the two cylinders?

 

[emckelvy]

Re: Rust on spark plugs, Compression OK, is motor bad?

Sounds like it sat in the salt water for a long time. It may have been that those 2 cyl's in particular were open to the salt air.

Run the motor then pull those plugs and check for water. If it's sucking in significant amounts it should be evident on the plugs.

Since this is an older Salty Dog, it probably needs a thermostats/poppets (besides an impeller); and it wouldn't be a bad idea to change the head gaskets and pull the exhaust manifold to check/renew the inner baffle and renew gaskets.

Of course, Salty Dogs like to freeze-up all the bolts so that's something to consider. It could end up being a maintenance nightmare.

HTH & G'luck with that motor........ed

 

[Silvertip]

Re: Rust on spark plugs, Compression OK, is motor bad?

Rust on the spark plugs is not normal. It does indicate water intrusion.