314joey

Could be a thermostat going bad or sticking, if you can find someone with a heat sensor you can check everything, some bigger marinas have them.

T_traylor1

That's the only other thing I could think was thermostat. Can one for any Chevy be used like from auto parts store? Or does it need to be from mercruiser and what temp?

underpsi68

A bad thermostat wouldn't cause low water pressure

T_traylor1

Then what else could be the cause

US1 Fountain

Plugged hose thru transom

With both high temp alarm and low pressure conditions, you have low flow issues

In your pic, did you look at all the vanes and the full length of them to make sure they arent broken off inside the housing, vs just glancing at the end shot?

T_traylor1

Yes tool it out and it's all good

T_traylor1

Since it's apart I did order a new housing and impeller, water was flowing back thru the drive pretty well last night

HyFive578

Also check hoses for cracks...if you have an air leak, you could be losing suction.

US1 Fountain

True enough.

Do you have a freshwater flush system?

ROB FREEMAN

it would if it was stuck open. and not moving enough water to get it to close .. feel youre exaust if feels hot youre clearly not moving water .or enough water .. easy way to tell ..exaust will feel warm to touch not hot ... if moving adaquate water past the or through the engine ..like for instance running without a t stat it takes large amounts of water to build water pressure as ther is no restriction .. becomes a strait through process .. i had to lower my water intakes half inch below boat to achieve 15 pounds of water pressure without a t stat ... good luck