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Hammermechanicman

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Customer brings in craftsman mower with tecumseh engine. Says it has run like crap since the day he bought it. It finally won't start. Look close at the valves. Had to clean a crap load of carbon off to see it. Valve is not bent and seat is not loose and stem tight in the guide. Customer said engine never been apart.
 

slomo

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Still looks filthy. Can see a ton of grit in the valve area and head bolt holes.What does it look like after you clean it?

slomo
 

Hammermechanicman

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I just cleaned enough to see the valves to see what a good job the factory did. The guy said just save it if you can and don't put much it it. I just did the red scotchbrite under the valves and spin to clean valves and seats. It ain't spotless. Reused the head gasket, new spark plug, air cleaner, sharpen the blade and clean main jet in carb. Guy is a good customer and will be happy as long as it runs. Not my finest work but gets the customer what he wants. This is one of those craftsman mowers nobody puts a lot of money into.
 

slomo

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I just cleaned enough to see the valves to see what a good job the factory did. The guy said just save it if you can and don't put much it it. I just did the red scotchbrite under the valves and spin to clean valves and seats. It ain't spotless. Reused the head gasket, new spark plug, air cleaner, sharpen the blade and clean main jet in carb. Guy is a good customer and will be happy as long as it runs. Not my finest work but gets the customer what he wants. This is one of those craftsman mowers nobody puts a lot of money into.
So leaving a filthy engine with grit and dirt in the valve area and bolt holes, last I checked, doesn't prolong the life of said engine. You were right there. Solid chance to do a professional job and sleep well at night. Guess I'm more anal LOL. Maybe I have more free time LOL.

Okay, surely a couple shots of carb cleaner and a nylon brush wouldn't....... Never mind. Guess they wanted their mower fixed for free. I need to visit your shop with my junkers.

slomo
 

Hammermechanicman

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I cleaned all the grit out. I charge by the hour so does he want me to spend a lot of time making A $100 mower spotless or enough to get it to run. With all i did it is still close to $100. To do it right i should have torn it down and done a complete valve job scrubbed the block in the parts washer reassembled with all new gaskets at $40/hr + parts. I gave the customer exactly what he wanted at a price he thought was fair. It's OK i have plenty of business and so far nobody has asked for their money back.
The picture is showing how the valves are not centered in the seats. It appears they use some kind of pilot in the valve guide to cut the seat to match the valve. One side is way thinner than the other and valves are not centered. Both valves are this way but the intake is worse than the exhaust. It came in for not starting with very little compression. The intake valve was so carboned up on one side that it wouldn't seat.
 
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tom3

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I think that engine was designed for those special hi-performance offset valve heads. Did you manage to get a decent looking pattern on the seats with the lapping?
 

bertsmobile1

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It is a side valve engine so the slightly skewed valve will make zero difference unless it has flow passages in the head.
he depth of the sea will make a difference.
You need to talk to silly old fools ( me included ) who try to make old side bangers more than 20% fuel efficient.
Remember it is a lawn mower engine designed to be one thing,,,,cheap ,
 

Hammermechanicman

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I didn't lap them. I use red scotchbrite and turn the engine till the valve opens and slip some scotchbrite between the valve and seat. I turn the engine till the valve closes on the valve and i turn the valve and scotchbrite to clean the seat then turn the valve to clean the valve face. It works pretty good to clean carboned up valves.
 
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