mercruiser 165 trim pressure problem

[greg maronick]

I have a 1978 mercruiser 165 drive with the older (prestolite?) type trim pump. I have had trim cylinders blow up (split) several times. I am quite sure it is because the reverse lockout micro swich comes out of adjustment allowing the trim pump to run during reverse lockout, but total destruction of at least one of the cylinders.?? Does this sound correct?? I have replaced the valve body in the trim pump, so I know it is not presure relief problem.

[Tech Support]

I am not sure what is going on. The pump should not produce enough pressure to split the trim cylinders. The reverse lock out should just hydraulically lock the fluid to prevent movement. Other than hitting something I can't see enough force going to the cylinders to split them.

Tech Support