Merc 150 Overheating

[krobarge]

Have an '83 Merc 150 that alarms (overheating?)after 1 minute when I bring rpms up to about 3500 Motor has not been run since last fall, just getting it ready. Peeing great, water is hot but not sure if this is normal. Both sides of block ejecting water. Water pump not old. Used in salt and fresh water. Any suggestions?

 

[dakk1]

Re: Merc 150 Overheating

I would suspect the impeller. Just replaced one that was a year old with very few hours on it. It looked like a dog had been chewing on it. It would still pump water at low RPM's though.<br /><br />Dave..

 

[KCLOST]

Re: Merc 150 Overheating

What type of alarm are you hearing?<br /><br />Is it a constant "beeeeeeeeeeeeeeeeeep"? Or an intermittant "beep,beep,beep"?<br /><br />The constant indicates overheating, the intermittant indicates an oil injection problem.<br /><br />Let us know...

 

[dakk1]

Re: Merc 150 Overheating

I didn't think 1983 had oil injection.<br /><br />Dave..

 

[krobarge]

Re: Merc 150 Overheating

The beeping is constant. Engine does not have oil injection. Water pump is 2 seasons old but has less than 20 hours on it.

 

[KCLOST]

Re: Merc 150 Overheating

Yep, your right-no oil injection!<br /><br />That impeller is the first thing you should check as dakk1 mentioned.... Does your engine have a poppet valve...<br /><br />I need your serial# to determine that...

 

[Coolmaker]

Re: Merc 150 Overheating

Also check the thermostats.......