used a crappy ear set flushing motor....

[whiterimedsupra]

I have a 79' checkmate with a 250hp chevy 350 and pre alpha 1 drive. I came back after having it out all day and it was dark. I hooked up the ears, turned on the water and let the boat run for about 10 mins while screwing around with the dash lights. I cut off the motor and all seem well, untill I then seen the garden hose laying on the ground do to the fitting pooped out of the ears. I hooked it back up and now it smokes, I definitly do not remember it doing it and it gets worse if you rev it. Unfortunetly the temp guage wasn't working but I know it got hot. Whats the best way to check a head gasket? I am leaning towards I warped a head, but any other ideas?

Also another weird thing is with the water running it takes a good almost minute for water to start coming out the transom after I start it aswell, I could have sworn it started circulating alot faster.

Anything special I should be replacing when I pull the heads? I know I need to do the manifolds because there are probly original on here (boat sat for last 11 years, untill I got it last year and used it all last summer with no issues)
Thank you for your help,
Matt

[whiterimedsupra]

Actualy could it just be that I burned up the impeller from running it dry?

[Frosty]

I think you should spend a little more time on diagnosing your prob before ripping into it.

[marshmat]

Pulling the heads wouldn't be my first reaction to a problem like this... that's major surgery and there are other things that could be checked first.
Such as:
- Running an outboard or sterndrive with no cooling water is almost certain to destroy the raw-water impeller; this is a routine maintenance item anyway, so I'd figure on rebuilding the water pump
- If you have a wet exhaust with flexible hose, there's a good chance the exhaust hose might have been damaged by the excess heat when the water failed
- Might be worth trying a compression test, this could give you a clue as to whether the head gasket might have blown out in one or more cylinders, among other potential problems

It's definitely worth the time to try to figure out what went wrong before you go crazy with a socket wrench.

Now, it wouldn't surprise me if after being run dry for as much as ten minutes, the head gasket might be in trouble. If you do end up having to open it up, you'll probably end up replacing a lot of seals, gaskets, etc. It is, after all, a 30 year old Chevy.

[PAR]

There are several ways to check your engine for a blown head gasket without tearing the heads off.

The raw water impeller is cooked, get a new one.

If you have a heat exchanger, check it for oil contamination. Check the oil for water. In short, if this type of diagnosis isn't something you can understand, then take it to someone who knows boats.

The heads on your boat are iron which don't warp easily. A lot of shops will perform a diagnose for a small fee. At which point you can elect to make the repairs necessary yourself.

Considering the basic nature of your questions, I'd recommend you take it to a shop. There are things they'll do, which you will not think off and it can mean the difference in a long term repair or one that you'll be redoing every season or two.

[whiterimedsupra]

Thanks for the replys, I am going to order the impeller and housing. And I need to replace a U joint while I'm back there aswell. I havent toyed with it yet, but I will pull the plugs and look for contamination on them. I am just so used to cars with anti freeze to smell, or a closed cooling system you can pressurize to test...