It is highly unlikely that valve adjustment is your problem, that mostly affects OHV engines. Your flathead generally only needs the valves adjusted when someone has, "done a valve job" and done it poorly.

"I have broken two gear pinions and replaced one clutch"

Are you using B&S plastic (nylon) starter pinion gear? Well, I guess I should ask what the ring gear on the flywheel is as I didn't look it up and not sure I could tell anyway.

I do not post my correctly formatted address because of automatic "crawlers" harvesting addresses from all these lists.

Walt Conner
wconner5 at verizon dot net

Thanks Walt. I have tried that e-mail in proper format and can't get you. Mine is b_l_d@comcast.net. The gear pinions broken are briggs brand plastic gear pinions part #693059 now replaced with #695708. Today I bought another clutch and gear pinion but it's pouring rain in Mid TN and too wet to work on it. Without looking at it now. I'm having trouble understanding why the metal shaft going through the clutch and gear pinion (armature shaft?) would spin and the clutch and gear pinion will not spin while the gear pinion is engaged with the flywheel. It seems to work fine when plugs are removed. Im glad to hear about the OHV v flathead scenerio. Didn't really want to mess with valves, because it has been running good prior to this starter situation. One thing I might mention, coil was recently bad, and my neighbor drove this thing around without the engine cover on and running on one cylinder. I was not present the last tinme the gear pinion broke, but I believe the mower was running hot. Any ideas? Thanks.

Running without a cooling shroud plus only running on one cylinder is terrible.

You did not say what material your flywheel ring gear was made of. It will be aluminum, nylon or steel.

The starter shaft has a shoulder with flat places on it that fit into the starter clutch drive.

Walt Conner

Thanks Walt. Looking through the clutch where the shaft goes it is smooth white plastic and I don't see what locks it to the shaft. Oh well, I'll look at the shaft tomorrowow and maybe see what you are talking about if it quits raining. This mower is my elderly neighbor's and he keeps it outside covered up. I have helped him with this mower numerous times this year and keep having different problems. To answer your question, I'm 90% sure the flywheel teeth are steel 10% possibility they are aluminum. I know that they are not plastic like the pinion gear. Appreciate any advice. Thanks.

Replaced starter clutch (2nd time in 3 months) and problem solved. However, first several cranks are slow, then flywheel spins fast. Not sure about that. Thanks everyone. I tried Walt's e-mail as it should be entered and still can't get through. Oh well, I don't need the valve adjustment info so I can contact him if necessary through this great site. Thanks again.