150hp optimax reheating???

[dmsgms1967]

We are having problems with our 150hp mercury optimax. The alarm keeps going off because the engine overheats at low rpms.We have to stop and restart the engine and and give it some throttle.The engine is not cool itself at only low rpms. Giving it throttle cools the engine down and we then can go. If we just quick start the engine and travel at high rpm's, we're fine. But soon as we slow down, the alarm goes off. Help is needed. This boat has been to the marina three times for this problem. Any suggestions?????

 

[blouderback]

Re: 150hp optimax reheating???

Time for a new impeller. I'm surprised that the marina has not suggested this.<br /><br />

 

[180combo]

Re: 150hp optimax reheating???

Yep, replace the impeller. I have a 135 optimax and this resolved my overheating at idle trouble. I would be able to cool my engine by going into neutral and reving it to get the water pressure up. Do you have a smartcraft gauge? The water pressure should be near 2 psi at idle. HTH

 

[180combo]

Re: 150hp optimax reheating???

here is a lnk to the whole thread where I chased this trouble.<br /> http://forums.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=29;t=021192#000000