2000 merc 150 fouled plugs/oil leaking from upper tank

backtier

Recruit
Joined
Sep 17, 2003
Messages
4
Hello, I had a problem running my 150 today. It would not idle well and did not have enough power to get on plain. I removed the cover to find oil everywhere. The cap on the upper oil tank had split like they all do. While i had the cover off I also checked to plugs to find they were very oily. I replaced the cap and cleaned the plugs. I put in again only to find that it still ran bad and was still leaking from the new cap but from under the threads now. I removed the plugs again and they were fouled again. Could there be too much pressure in the oil system causing the leak and excess oil in the fuel. The motor did not smoke much at all so I am really confused. Thanks
 

backtier

Recruit
Joined
Sep 17, 2003
Messages
4
Re: 2000 merc 150 fouled plugs/oil leaking from upper tank

Today i pulled the plugs off and checked for spark which was good at all cyl
 

gss036

Commander
Joined
Jan 18, 2003
Messages
2,914
Re: 2000 merc 150 fouled plugs/oil leaking from upper tank

Check your boat oil tank about 15 minutes after shut down and see if it is still holding pressure, if so, the check valve probaly not working, it is suppoed to bleed off the tank pressure. It is located on the lower port side of the block. Follow the lines backwards to locate it.
 
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