Volvo Penta 4.3 Pwtr Overheating

[aristo_craft_19]

I bought a 1999 larson with a 4.3 GL PWTR a few months back and having an issue with it overheating. When i first got the boat i noticed that the exhaust hose on riser had dry rot and was taking on water so i replaced. The boat ran fine and then while out i felt a loss of power so cut engine off. When i went to restart the starter just spun and was not engaging the fly wheel so i replaced the starter and boat starts fine now. Took the boat back out and now its overheating at high rpms. I replaced the thermonsat and look at the water pump impeller and that seems to be fine but from what i can tell there was no gasket used on the thermostat housing but two o rings in place. I am just trying to figure out where to start looking? Thank you in advance for any help you can give me.

 

[Don S]

Re: Volvo Penta 4.3 Pwtr Overheating

Yes, there should be only 1 oring, no gasket.
Seawater Pump 4.3GLPWTC, 4.3GLPWTR, 4.3GSPWTC, 4.3GSPWTR, 4.3GIPWTC, 4.3GIPWTR, 4.3GIJWTR, 4.3GSJWTR - 7797466 - Volvo Penta
2 orings probably caused an air leak and it won't suck water up to the pump.

You say you checked the impeller, did all the vanes straighten out completely in a few minutes? If not, replace it.
Volvo recommends those impellers get replaced yearly.