Thermostat housing dry after running engine

[weezyq8]

Hello,

I recently got 1963 Johnson 18 running after it sat in a barn for about 15 years. I replaced the thermostat already, and I was running the engine in a barrel yesterday and noticed that it seemed to be getting hot. After I shut it down, I pulled off the thermostat cover to see if it was getting water. The thermostat and the coolant channels leading to it were dry. While it was running, I saw water spitting out close to the exhaust port though. I haven't replaced the impeller yet, but I have ordered one already so I will do that soon. But it doesn't make sense for the engine to be spitting out water while the thermostat housing is dry...has anyone seen this before?

Thanks.

 

[gm280]

Re: Thermostat housing dry after running engine

It could be one of the impellor limbs/blades broke off and logged in the water passages. When you do get your new impellor in and take the LU apart to replace it, look for anything that has clogged up the water passages. Flush them out all the way through before reassembling again. Problem should be fixed then...

 

[Bosunsmate]

Re: Thermostat housing dry after running engine

Yep i agree with gm280. Check the old impellor has all its blades on it.
Also back flush down through the thermostat housing to check for flow backwards
Also if your impeller is really worn or there are other problems such as worn pump housing your pump might got get the pressure to fill it up to the stat level, only the lower level and thus it will get out the exhaust port but not up to the stat housing.
Also make sure the leg is sufficiently submerged in the tank, you should have it at least 8cm higher than the waterpump level

 

[weezyq8]

Re: Thermostat housing dry after running engine

How do I backflush the system? I'm assuming I would need high pressure water to squirt through the channels? I see what looks like mouse droppings under where the stat usually sits...that can't be a good sign

 

[Bosunsmate]

Re: Thermostat housing dry after running engine

Just a normal hose should do, too much pressure can be damaging.
Just check you have flow
Barn rodents are such active rascals!

 

[Bosunsmate]

Re: Thermostat housing dry after running engine

Also check your sparks to make sure no water is getting on sparkplugs turning them a milky oil colour or steam cleaning them

 

[weezyq8]

Re: Thermostat housing dry after running engine

Great, that sounds like a plan. Thanks!