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My son took out our 2004 800 Ho and put a stud through the exchanger. Motor over heated to the point it locked up. towed it home and later after it cooled down the pistons freed up. Terrible compression. So i pulled the jugs and was suprised they looked great. Ordered a (2) piston and gasket set and installed new gaskets, orings, pistons, rings. Then replaced the heat exchanger. Fired it up and ran great. rode it for a hr or so. Next morning it would only run on one cylinder and back fire and so. checked plugs and seemed wet, swapped them out and started it up ran good but steamed up the garage terrible. So now I figured he warped or cracked the head. I ordered a new head and 2 jugs!!!! Put it all together and fired it up and to my surprise it was good......no steam. Next morning try it again and guess what?..................STEAM.

Now Im down to 3 things,

1.water pump seal bad and letting coolant into crankcase

2. internal crack in crankshaft case

3. Coolant getting into the carbs through the passage way that heats the carbs.

Please help
 

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My son took out our 2004 800 Ho and put a stud through the exchanger. Motor over heated to the point it locked up. towed it home and later after it cooled down the pistons freed up. Terrible compression. So i pulled the jugs and was suprised they looked great. Ordered a (2) piston and gasket set and installed new gaskets, orings, pistons, rings. Then replaced the heat exchanger. Fired it up and ran great. rode it for a hr or so. Next morning it would only run on one cylinder and back fire and so. checked plugs and seemed wet, swapped them out and started it up ran good but steamed up the garage terrible. So now I figured he warped or cracked the head. I ordered a new head and 2 jugs!!!! Put it all together and fired it up and to my surprise it was good......no steam. Next morning try it again and guess what?..................STEAM.

Now Im down to 3 things,
1.water pump seal bad and letting coolant into crankcase
2. internal crack in crankshaft case
3. Coolant getting into the carbs through the passage way that heats the carbs.

Please help
Check the base of cylinders, I have had two occasions where the base wouldn't seal good to base gasket after a bad burndown and warped the base, then had to take .012 off bottom and make it up with a thicker base gasket
 

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Are u talking on the jug or base side? Did u pull the motor out? I put another set of jugs on the motor.
On the jug side, even if you put in re-plated jugs on, probably still could happen, I don't believe they always check that when they re-plate so you could have someone else set from a bad burn down, both mine were having that problem even after a re-plate

You shouldn't have to pull motor out just pull off jugs and check them, but do a leak down test before you pull apart, if you have the stuff to do so to make sure and to rule out any other leaks, so you don't have to keep taking apart
 

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Could be a just a pinched base gasket as well and not be warped

just throwing out possible causes that I've been through to help you out, it's nice to know all the possibility as you troubleshoot so your not chasing your tail, ask me how I know this :-(
 

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I bought an 600ho that had overheated. Was rebuilt using aftermarket gaskets, orings. I also had a coolant leak. I replaced the orings with OEM and the leak went away. Perhaps coincidence, maybe they got pinched on initial install?
 

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I'm not 100 percent sure on this but if the water pump seal was bad it would not get into combustion chamber because that seal goes into sealed crank bearings in a oil bath and not into the combustion chamber, but there is a double seal there and would just dump coolant out bottom of motor

Maybe someone else can chime in and confirm this?
 

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With the new.cyls and head and steam/coolant smell? Next morning could mean coolant is still in the pipe/can that needs flushed out,,gas works and air hose/careful

Coolant doesn't burn very well so it.gets pumped.into the exhaust
 
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