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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.

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

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.

Hammermechanicman said:

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.

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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

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.

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?

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 ,

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.

bertsmobile1 said:

Remember it is a lawn mower engine designed to be one thing,,,,cheap ,

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You got that right. We don't call them Crapsman with a Trashcumseh engine for nothing.

No wonder why Tecumseh went out of business!

Not their fault.
They made WHAT THE MARKET WANTED TO PAY FOR
Unfortunately when you are servicing the cheapest end of the market, the second some one offers a cheaper engine your sales plumet.
Bottom end profitability requires massive volumes because the margins are very thin so a 5% loss in volume will send you to the wall
And Chinese engines are about 1/2 the price of Tecumseh engines.
Down here Tecumsehs were so cheap that mower shops replaced your engine rater than doing simple repairs
Then they swap the blower housings so it looks like they fixed your old engine .

I am a fan of the old cast iron Tecumseh engines. Still have 2 of them on equipment that runs. It was sad to see how they, just like Briggs, went downhill because if the market.

No one to blame but our own greedy selfish selves
We want more & more for less & less and never think about the consequences of our actions
Down here the big supermarkets started a milk war where milk ended up being retailed for less than the production cost
Now there would be very few Australians who could not afford to pay $ 1.50 / l for milk
But did they spur the supermarket branded cheap milk & buy full price dairy branded milk ?
Nope they happily saved $ 4 week on milk and then complained to the government when all of the milk processors went broke along with the farmers, of which quite a few shoved the 12 gauge in their mouths and blew their brains apart .

Is the valve guide that worn? Or does it even have guides, meaning the block is either severely worn or the hole for the valve stem was mislocated from day one?

The valves are tight in the guides no slop. The thing runs but the grind in the valve seats is really off center

How could they have ground the valve seat off center? I've ground a few valve seats and the stone is guided by a collet-type tool that centers itself in the valve guide.

Best i can tell the holes bored in the block for guides not matched up with the seats and a pilot in the guide was used to grind the seats. The seat is paper thin on the cylinder side.

Hammermechanicman said:

Best i can tell the holes bored in the block for guides not matched up with the seats and a pilot in the guide was used to grind the seats. The seat is paper thin on the cylinder side.

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At the first glance of that pic, before you explained it, it almost looks like it has too small of valves in it.

bertsmobile1 said:

Not their fault.
They made WHAT THE MARKET WANTED TO PAY FOR
Unfortunately when you are servicing the cheapest end of the market, the second some one offers a cheaper engine your sales plumet.
Bottom end profitability requires massive volumes because the margins are very thin so a 5% loss in volume will send you to the wall
And Chinese engines are about 1/2 the price of Tecumseh engines.
Down here Tecumsehs were so cheap that mower shops replaced your engine rater than doing simple repairs
Then they swap the blower housings so it looks like they fixed your old engine .

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I don't buy that.about people wanting cheap engines. Most people have over $1,000 cell phones. All you need is a dial tone LOL.

slomo