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LA140 B&S 23HP I/C OHV Valve Adjustment ?

5756 Views 6 Replies 5 Participants Last post by  MichaelTJD60
Hello. Newbie here. I recently purchased a used 2007 LA140 with the Briggs 23 HP engine. Overall it is in very nice shape but needed a few adjustments. It has the common problem of hard starting, which from reading other threads is valve adjustment related. I've downloaded the L100 Repair manual found here and watched some of the valve adjustment videos on Youtube and am confident that I can do this job. Just have a couple questions.

How do I verify the adjustment spec for my particular engine? I found a document that listed the adjustment spec as .004-.006" for numerous B&S V twin OHV engines but don't know if mine was on the list. I did not see the adjustment spec in my owners manual but maybe I missed it.

Should the valves be adjusted to spec. hot or cold? It seems to be more difficult to restart after it's hot so clearances probably change slightly as heat builds in the engine.

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Valve adjustment on a single cylinder is a little different than a twin. On a single cylinder you find tdc and adjust both valves. You can also check where cylinder is at by using a stick or dowel down the spark plug hole.

On a twin, you need to find tdc on one cylinder and adjust the valve clearance much like a single cylinder. But the second cylinder, you need to go through the same process to find tdc for that cylinder. Then you can adjust the valves once tdc is found.

I usually do .004 intake, .006 exhaust. Intake valve will be closer to the carb, exhaust will be close to the exhaust pipe. Usually a sign you are on tdc, is when the cylinder is all the way up closes to the spark plug hole. But also both valves are loose or have some play. You can usually wiggle them around. If one of the valves are tight, as if it's pushing on a valve. It's not on tdc yet, or it's possible something is wrong like a bent pushrod. Speaking of which, make sure the pushrods are not bent, and they can move freely.

Years ago I had a cx honda that was always notorious for valves. I would adjust those things every 2 months because they were old and would just work loose. They weren't the worse to work on. You had peeper holes you could look at the flywheel and it would say LH or RH. Made finding tdc for each cylinder a little easier.
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