1989 mercrusier 3.0 need help

[newboater2day]

i have a 89 searay with a 3.0 mercruiser i been haven low rpm's been checkin around and had low compression in each cyclinder talked to searay they said it sounded like a blow head gasket since i have no water in my oil or steam. tonight i pulled my head and the head gasket looked fine the exhaust gasket was broken in 2 places.. my question is when i pulled the head there was water on top each piston but still not water in oil. got any suggestions on what to do.. the head looked normal wear and the valves had some carbon but not bad but u could see on the exhaust manfold there was lot of black build up where gasket had broke.. dont know where to start???

 

[jerryjerry05]

Re: 1989 mercrusier 3.0 need help

If all 4 cyl had low comp it sounds like it wasn't taken right. It's extremly rare for all cylinders to have low comp with a blown head gasket.If the comp is really low then the water must have gotten in to all cylinders (rare again)from the exhaust manifold or riser. Do a flow test on the man/riser.A good riser should flow as much as in and out with no buildup of pressure.Check with a light for holes and rot. Let us know.Jerry

 

[newboater2day]

Re: 1989 mercrusier 3.0 need help

thanks for the reply when i did a compression test they where as follow

1 90
2 30
3 30
4 80

i been told the 3.0 should have 140 on compression.. and there was about 1/2water on top each piston and water came out head bolt holes when i loosed them..

 

[Don S]

Re: 1989 mercrusier 3.0 need help

Either that engine is complete junk, or you did the compression test wrong. Follow this Mercruiser service bulletin for testing your compression.

http://www.boatfix.com/merc/Bullet/97/97_25.pdf

 

[newboater2day]

Re: 1989 mercrusier 3.0 need help

this is a update from a post i did a while back i broke down and took my boat to the shop it took a while for them to get to it and it turns out that the 2 and 3 valves where burned so they sent it out to the machine shop the rest of the motor looked good rings ok just needs a valve job and the head redone shold be back in the water soon.. thanks for the reply don s