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Tecumseh 4.5HP ; both valves mis-aligned/angled

gcaiola's Avatar

Join Date: Apr 2005
Posts: 2

04-21-05, 04:48 PM   #1  
Tecumseh 4.5HP ; both valves mis-aligned/angled

I'm new at repair efforts, so any stupid assumptions I may make and any poor terminology below........

I can't start this Craftsman mower after trying all the basics. I eventually removed cylinder head. Piston and valves move ok , but both intake and exhaust valves are slightly angled (maybe 5-10 degrees from being flush with seats). In other words, one half of a valve is seated while the other side is very close, but not quite seated. The exhaust valve is a bit worse, and that's probably why it was totally nasty with crud. But what's weird is that both valves are both mis-aligned at the SAME angle. I don't have a valve spring removal tool so all I've done is clean them as well as possible.

I rotate either valve and the angle/mis-alignment doesn't "move" with rotation--implying I think that the valve stems are not bent--as if the problem is what they are mounted within. However the cylinder/block (not sure of term here) seems to be a single solid cast of metal. So I can't imagine what has caused this and how to fix it. It's almost as though the block was milled out wrong when manufactured. But the mower worked for a few years so I'm confused.

Any thoughts? Thanks in advance...

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mla2ofus's Avatar

Join Date: Jan 2005
Posts: 478

04-21-05, 11:52 PM   #2  
From what you describe it sounds like both valve seats are loose and misaligned with valves. Try tapping gently in the center of each valve to see if this will get the seats aligned with valves. If so center punch block metal around each seat to recrimp seats in block.
Hope this helps,

cheese's Avatar
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Join Date: Jul 2001
Posts: 16,569

04-22-05, 09:23 PM   #3  
Sounds like the engine overheated and distorted, maybe even allowing the seats to come loose as mentioned.

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God bless!

puey61's Avatar

Join Date: Apr 2004
Posts: 3,224

04-23-05, 05:39 AM   #4  
Bear in mind that the valve guides are NOT perpindicular to the bore, they are at an angle to such...Albiet slightly. I'd pull the valves and check the seat conditions and then, if OK, correct the valve clearances, if needed.

gcaiola's Avatar

Join Date: Apr 2005
Posts: 2

04-28-05, 10:27 AM   #5  

thanks to all 3 of you for the information....Time to dig in deeper now.......


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