Merc 50 4-stroke problem

[earthraper]

Hi forum members,<br /><br />I hope that someone here has an idea. My friend has a 97(?) Mercury 4-stroke 50hp. Up until last year there was never a problem. What happens is that once in a while when going at full speed, it will bog down, blow steam, and get water in the crankcase. This is not an everytime occurance. The dealer has done compression tests and claimed there was water in the gas.<br /><br />I'm not buying that. Sine having been to the dealer, the motor has done it again. Any ideas as to what to look for? Was this a problem with these motors?<br /><br />Thank you in advance!!!<br /><br />ER

 

[almost retired again]

Re: Merc 50 4-stroke problem

Hello Capt. FU<br />I would hazard a guess that you either have a blown head gasket or a cracked block. I think that's about the only way water can get in to the top of the cylinder to give you steam. I would hape it's the head gasket.<br />lots of luck

 

[SeaDawg]

Re: Merc 50 4-stroke problem

Water in the gas will not give you water in a 4 stroke engine crankcase. It would for a 2 stroke.<br /><br />I agree with almost retired again. Do another compression check (different dealer if he argues with you) and look for a blown head gasket (hopefully), or a cracked cylinder. Have him tell (or show) you the compression readings, they should all be with 10% of each other.<br /><br />Some of the real mechanics here can give you other helpful advice too, I'm only a lightweight compared to them.