1995 OMC Cobra 5.8L overheating issues

[j hunt boat]

My four winns started overheating just after starting. I have looked online and it seems that it is supposed to have a water circ pump (belt driven). Does it also have an impellor in the lower unit?? and the 3rd cause could be the thermostat. how to determine which is the cause?? One of the impellors was changed a few yrs ago, and not used much. never changed the stat.

also, battery went low. does anyone know if the water circ pump AND the alternator are on the same belt?? I am not at boat to check. Thanks.
John

 

[Lou C]

If the power package is really a ‘95 then it would have the impeller mounted on the engine like a Volvo in addition to the typical automotive style (but marine version) circulation pump. The older OMC Cobras (1986-1993) had the impeller in the outdrive like mine. If it’s overheating that fast the impeller May have failed; this is usually due to water not getting up to the impeller. You might also have a stuck engine thermostat or clogged exhaust elbows (rust clogs the cooling passages).
Not sure on the belt question you might take a look on
www.crowleymarine.com
www.marineengine.com

Both have OMC parts diagrams