CV461S Stopped running.

joea99

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You don't need a "leak down" tester just to find if compression is leaking from a valve, just make sure both valves are closed or looks closed....remove rockers just to be sure, and put air in the spark plug hole....if a valve is stuck open, you will hear the air coming out, THEN you must pull the head to see why!

I can give that a try to confirm what I just saw. I put the scope barely in the spark plug hole and managed to see the exhaust valve. To be certain, I put a lever in the valve lash gap and could see the valve moving as I levered it. Never closes completely apparently.

I'll check the price of a new head vs getting a new seat installed, before I do anything else.
 

Fish

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At tdc, both valve stems should be at an even height, generally.
Pull the head before ordering anything.
 

joea99

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There are a lot of used head on ebay, that match the part number, but list for different engines. Some of them look good, some are pretty groady. Same rockers, etc? Safe to use old head bolts, or get new?
 

joea99

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Proceeding to remove head. Found an astounding amount of debris packed into the cooling fins. Apparently just blowing it out once in a blue moon is insufficient, when mice build a winter home in there.

Anyway, I suspect more serious problem may be found. Of course a "random" thunderstorm has interrupted my labors, but, when I get the head off, are there any tell tale signs in the cylinder wall or piston top I should look for, besides obvious heat discoloration and scoring?
 

Fish

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Look for scrathes, streaks, and if it has a noticable "lip" around the top.
You will likely readily see the problem, I still predict a loose seat.
 

joea99

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Look for scrathes, streaks, and if it has a noticable "lip" around the top.
You will likely readily see the problem, I still predict a loose seat.

So, if it is just a loose seat, is there a reliable and economic way to repair that, or just go with a clean looking head from ebay?
 

Fish

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I would look for a good used one if it was me.
 

joea99

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Having a VERY hard time removing the top two head bolts. They do move a few turns, with difficulty. Tried the usual things such as penetrating oil (Kroil) and threading in and out to loosen things, soaking again, etc.

The head is loose so I can actually soak the threads where they go into the block, but, feels like the want to gall, or are galled already.

Not sure if heat might be the answer, or, as has worked a few times in aluminum, using Break Free as a helper might. So far I have not tried an air impact, going gently forward and reverse and hesitate to do that, having sometimes been badly fooled by soft bolts.
 

joea99

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Well. Fish was right, a loose seat. Intake, not exhaust. Cylinder looks good, still has crosshatch pattern plainly visible and only a small arc on piston top where the it touched the seat.Mostly just wiped the carbon. Buuuut . . .

Broke the two reluctant bolls. I can drill them out, I suppose, but suspect the threads are well galled. Could do a Time Sert repair but the kit for head bolts runs over $400. I suspect there are very new around for rent and that the "not for head bolts" kits will not suffice,
 

bertsmobile1

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Drill em out then pop the engine / mower on a trailer and pop dowwn to your friendly Mower mechanic ( not a glass front retail shop ) or even a motor mechanic.
Make sure you have the new bolts in hand.
Most will do a helicoil on the spot while you wait.
I charge $ 20 each ( aus ) for helicoils ( any size ) and $ 40 for solid inserts cause they are a bit tricker to do.
 
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