Hi everyone, I have Briggs and Stratton engine #126T02-0795-B1. It's been getting harder and harder to crank and remain cranked, recently. Now, it does not crank, at all. The engine is reading about 25PSI of compression. I pulled the head and noticed a hugh carbon buildup. The head gasket looked blown. There was a bit of oil leaking from the bottom of the head. I cleaned the carbon and put a new head gasket on and am still having the low compression issue. I removed the valves and verified that the valve seats are still in tack and not loose. Can anyone help let me know what to check from here? Thanks.
Briggs and Stratton Push Mower Engine (Model #126T02-0795-B1)
- Thread starter hgoodw
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That is a fairly old engine (around ten years or better) and may have a worn out cylinder and rings. While had the valves did you lap them make sure they are sealing. Also the valve clearances needs checking as with the clearance tend to close up leading to lower compression. Plus it would not hurt the valve guides for wear as valve may set properly if they are badly worn.
Note engine does have an ACR so the normal compression is around 70-90 psi at cranking speed.
Note engine does have an ACR so the normal compression is around 70-90 psi at cranking speed.
Ok, thanks - Sounds like the engine may be done. It is about 12 years old. To answer your question, the valves are still out; I've never done any type of valve work like this. I will give it a try. Any good videos you recommend? Thanks.
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Personally I don't know of any video but I usually not looking for them either. Others here should know of some.
One piece of advice when adjusting the clearance is to file valve stem tips lightly and square. Check clearances often with springs install. And shoot for the higher clearance numbers as I said these tend to close up so that would give a long time between adjustments.
One piece of advice when adjusting the clearance is to file valve stem tips lightly and square. Check clearances often with springs install. And shoot for the higher clearance numbers as I said these tend to close up so that would give a long time between adjustments.
| Intake Valve | .005-.007 in (.13-.18 mm) |
| Exhaust Valve | .007-.009 in (.18-.23 mm) |