any boat mechanics around?

b_illymac

Soap Lake Posse
WFF Moderator
I'm having problems with a Johnson 115hp V4 1999 overheating. Water pump housing and impeller replaced. Pop it valves replaced. Head gasket orings replaced. Engine seems to run good. No obvious reasons why. Never given me issues before and been a strong engine. It's not a faulty alarm sensor as engine head temps checked.

Would trade beer/flies/soap lake bass intel to anyone that could help or even offer advice over a phone call or messages. This is driving me nuts.
 

veilside180sx

Active Member
Did you replace the thermostats?

If they are stuck closed it’ll cause what you’re seeing. Runs great when colder but starts to overheat when it needs more cooling capacity.
 

b_illymac

Soap Lake Posse
WFF Moderator
Did you replace the thermostats?

If they are stuck closed it’ll cause what you’re seeing. Runs great when colder but starts to overheat when it needs more cooling capacity.
They are built into pop it valves. I might run it without the pop it valves and see how the flow is. Maybe I got a faulty one or something.
 

Rob Allen

Active Member
I'm having problems with a Johnson 115hp V4 1999 overheating. Water pump housing and impeller replaced. Pop it valves replaced. Head gasket orings replaced. Engine seems to run good. No obvious reasons why. Never given me issues before and been a strong engine. It's not a faulty alarm sensor as engine head temps checked.

Would trade beer/flies/soap lake bass intel to anyone that could help or even offer advice over a phone call or messages. This is driving me nuts.
Do you have a water pressure Guage. If so what's the water pressure at WOT?
 

iggie

Active Member
Is it overheating for sure or just the warning. I had one doing that and it was warning sender went bad.
 
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WAS

Active Member
Is the impeller a press on shaft or keyed? Had a pressed on impeller spin on the shaft one time that gave me fits.
 

Mike Monsos

AKA flyman219
WFF Supporter
I had an impeller that had been installed backwards once, check that.
Yes the rotation on installation has to be correct for the fins to properly move the water through the motor. Also the connection fitting (tube) from the pump housing to the tube inside the casing might have missed the mark sending the water just through the engine casing.
 

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