cooling problem

[shaenjay09]

ok here we go. i have a mercruiser 3.0 with alpha 1 gen 1. my boat over heated. i pulled lower unit and impellar was shot. so i put in a complete water pump kit and t-stat. boat ran great for 3 weeks. 4 week started over heating at idle. any kind of gas and was fine. so i figured i got sand in the impellar and ground down the tips. nope, pulled the lower unit and impellar looks brand new. so im stumped. what do i do now. marinas out not enough cash for that. can anyone help???

 

[Bifflefan]

Re: cooling problem

First, does it run hot on the muffs?
Check the V belt and make sure its tight.
Remove and check all the hoses for pieces of the old impeller and anything else that may be clogging them.
Check the circulating water pump and make sure the shaft is turning the impeller in it.
Do a compression check, leak down check and look at the oil, you may mave blown a head gasket.

 

[shaenjay09]

Re: cooling problem

i dont run it with muffs i put a barrel with the water line above the intake holes on the lower unit. so you think a blown head gasket might be the prob?

 

[Bifflefan]

Re: cooling problem

i dont run it with muffs i put a barrel with the water line above the intake holes on the lower unit.

If your running it in a barrel, you must have the water above the impeller pump in the leg, not just above the inlets.
Use muffs, you will be way better off.

so you think a blown head gasket might be the prob?

You read the begining and the end, but didnt read the middle of what I said.

 

[Don S]

Re: cooling problem

If your running it in a barrel, you must have the water above the impeller pump in the leg, not just above the inlets.

No you don't. They better work with the intakes only covered. If it does't pull up from the intakes, there is a problem.

 

[Bondo]

Re: cooling problem

i pulled lower unit and impellar was shot. so i put in a complete water pump kit and t-stat.

Ayuh,... Did you find ALL the pieces of the old impeller,..??

If not, I'd guess parts of it are blocking the flow...

 

[shaenjay09]

Re: cooling problem

so were do i start looking now?

 

[dingdongs]

Re: cooling problem

pull the 1" pipe off that leads along your rocker box that attaches to thermostat housing.start engine with muffs briefly and see if lower is pumping water along pipe.if not stop engine .This tells you it is lower or blocked pipework or you may not have installed everything correctly.tube/key on impeller etc etc.

 

[shaenjay09]

Re: cooling problem

took out drive apart and this seal for the water line was pretty bad could that be the prob?

 

[dingdongs]

Re: cooling problem

if you have access to a hose pipe stick it in hole whilst engine is running and monitor.if all is ok its your waterpump impeller in leg.make sure rubber tube behind housing is not split .did you try removing hose as my other post before removing leg too?

 

[Chriscraft94]

Re: cooling problem

Just joined the forum and was wondering if you got your overheating problem fixed. I had a similar problem where it woild only heat up when running slow and the outdrive down. Turns out it was the hose from the outdrive to the boat, when down it was worn and partially kinked off and got worse when i turned to the left. Took a while to find the problem because the outdrive was stored in the up position when on the trailer.