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Tecumseh OHV valve lash issues...

Posted by mikeinmadison (My Page) on
Thu, Apr 26, 12 at 15:29

Thanks for any help! The motor is a 24hp Tecumseh V-twin and once started, it runs great. The problem is that it is very hard to crank, despite my best efforts to get the valve lash right. (with plugs out, the starter cranks it very fast -- starter and battery are good) Can someone walk me through the process of adjusting the valves so that this compression release problem is gone? I have tinkered with the valves a lot and can't seem to get it right.
Thanks again for any help!!
Mike


Follow-Up Postings:

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RE: Tecumseh OHV valve lash issues...

Sure you got the brand correct?????????

What's it on?


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RE: Tecumseh OHV valve lash issues...

It's a White Outdoor GT950H. Tecumseh OV691 24hp OHV. I've followed the instructions in the manual for adjusting the valves, but it's still very hard to crank. Two starters used, new battery with lots of amps. It's very difficult to turn by hand, which is why the starter doesn't like it...


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RE: Tecumseh OHV valve lash issues...

Looking in the Tecumseh BSI, it says to use the 695244A service manual.

That doesn't really mention your engine, but the OV engines mentioned are all .004" intake & exhaust with the piston TDC.


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RE: Tecumseh OHV valve lash issues...

Hi
I've adjusted the valves to .004 TDC on compression stroke, and one cylinder continues to prevent the starter from cranking the engine because there's too much compression. I'm wondering if there's anything else I can try before accepting that the compression release mechanism is shot. Thoughts?


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RE: Tecumseh OHV valve lash issues...

There's a distinct possibility that this engine uses a centrifugal arm on the cam, instead of the ramp type CR.
The manual mentions "some" engines equipped that way. I simply don't know.

The manual is rather foggy on this. The fact your engine isn't listed even though the BSI manual refers to it for your engine???

You might try doing a web search for your engine and possibly you can find a "correct" manual.


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RE: Tecumseh OHV valve lash issues...

I have the manual for it, on my home computer. Is there anything else I might try before accepting that it'll have to be torn apart?


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RE: Tecumseh OHV valve lash issues...

I guess the last resort is to read the manual closely on the engine reassembly procedure and see if it mentions or shows a "lever" attached to the cam shaft.


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RE: Tecumseh OHV valve lash issues...

I found this link for a "691" V-Twin.
It shows a mechanical release on the cam.
parts 253, 254

Here is a link that might be useful: VTX-691


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RE: Tecumseh OHV valve lash issues...

Thanks Bill
Is there a test I can do to be pretty sure the compression release isn't operating properly? This motor has been tons of fun -- replaced both heads when valve guides came loose. The first one coincided with me finding a cooked mouse, so I thought that side overheated. The other side did the same thing though, and air flow around it was fine... One carb has been tempermental...
So, how much of a hassle is replacing the compression release mechanism? Time? Pain in the a$$?
Thanks!


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RE: Tecumseh OHV valve lash issues...

It's a pretty major engine disassembly.


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