1988 XP150 Overheat alarm

[mcgreavster]

My 1988 150STLCCA had the dreaded overheat alarm go off on me the other night. Water was still coming out of the tell tale when it happened, I shut motor off immediately. Earlier in the day I noticed my RPM gauge quit working, when I first purchased the boat 8 years ago the RPM gauge wasn’t working and replacing the rectifier fixed it. Putting two and two together with the rectifier being water cooled I’m guessing both overheating and rpm gauge not working are related.

My knowledge of the water cooling system is pretty limited, outside of the thermostats I’m not sure what my issue could be. Anyone have any ideas what steps to take to troubleshoot this?

Thanks!

 

[racerone]

Some might argue.----Fact is that water from the tell tale does NOT circulate through the block.-----It indicates that water pump is working.----There likely is internal blockage.-----Remove cylinder heads.-----Look for ' water diverters " as they guide water around the block.-----Remove water jacket covers on the heads.-----Check for poppit valves being stuck.

 

[mcgreavster]

After a few busy weeks I’ve just placed an order for new Thermostats/poppet valves/deflectors and all new gaskets/grommets.

If I’m understanding this right, the cylinder head gasket gets no compound sealer, just the gasket…correct? But the Water jacket cover gasket and thermostat cover gasket both get double sided compound sealer?

Is there a substitute for the OMC sealer compound?