overheated engine damage

[1badfish]

I have a chrysler 45hp mod # 459he. I ran it gently for a few hours and it seemed to be fine. After running it full out for around 15 min I throttled back and it died. I couldn't get any power out of it after that. In fact the only way I can keep it running is to use the fast idle and tap the choke, put it in gear and it dies. I started it in the driveway and had no water through the water pump.
If it over heated but will still run even poorly what kind of damage can I expect and how difficult is it to fix for someone with decent mechanical skills.

 

[maxum247]

Re: overheated engine damage

Pull the spark plugs and see if there fouled, getting hot if run long enough might have fouled the plugs and it doesn't want to idle on them!
Do a compression test and see what the numbers on the cylinders are, cylinders should be within 10-15 psi of each other.

Sounds like your going to need a new impeller before trying to run it.
Check the compression and plugs first though.

Report back with what you find.

 

[1badfish]

Re: overheated engine damage

I checked the spark plugs they had what looked like oil baked on them, so I put in a new pair, compression seemed fine both cylinders around 70. I flushed the cooling lines and its pumping around 1 gpm now. I still plan on changing the impeller, but it will do for testing. I ran it for 20 min in the water full out, It didn't over heat, it ran great. I stopped for an hour and when I went to start it again it wouldn't idle. I kept it running by tapping the choke. once I got the rpms up it would stay running, but would die if I let it idle. The new spark plugs were dry but had the same baked on sticky oil fouling on them. I'm using a 50:1 fuel oil mix.

 

[maxum247]

Re: overheated engine damage

Carb may need cleaning or adjusting!
Make sure the carb is tight on the mounting surface.

 

[ck85abc3]

Re: overheated engine damage

If the gauge is correct, 70 psi is to low.