1959 QD20 10 hp overheat

[jonesg]

I got this johnson 1959 10hp last yr for $100 .

I went thru the ignition system, installed a new water pump impeller.

But it is running too hot, water sizzles and steams when drizzled on the head and its too hot to touch.

Runs fine til it gets hot.!


The original impeller was broken up.
What do I need to do next, I was thinking thermostats as everything else so far has been completely worn out.

The engine is running cooler than it was but still ends up becoming too hot.
I've got it in a bucket of water covering the plate just over the prop, antiventilation plate?

I have a carb rebuild kit but so far it doesn't exhibit any problem with fuel delivery.

WHat parts should I order, I'm thinking thermo's and gaskets.

 

[Daviet]

Re: 1959 QD20 10 hp overheat

You need a bigger bucket, the lower unit should be submerged at least half way up the exhaust housing or more. You know the placement of the water pump in the housing, the pump needs to be completely under water. The pump will pump water very well but it will not suck water worth a darn.

When you removed the old impeller was it complete? Sometimes they will break apart and peices, if small enough, may end up blocking the water tube.

 

[jonesg]

Re: 1959 QD20 10 hp overheat

ahh ok, I'll try a bigger tub then.

cheers.

 

[jonesg]

Re: 1959 QD20 10 hp overheat

That did the trick, cooled right down.

thanks.!

 

[Daviet]

Re: 1959 QD20 10 hp overheat

Your welcome. That motor, with proper maintaince, will last forever.