I would suspect a head gasket blew, but you should have had noticeable blue smoke.

Thanks Bill,
I wonderd about the head gasket. But, I had no smoke whatsoever until it was shut off and then restarted. On the restart I had low rpm sputtering and thick black smoke only.

"and 0.01 for the exhaust (yes, the prescribed gap is .005-.007; I did this per suggestion of another expert online). "

I don't know who your "Expert on line" was but he is NO EXPERT. I'll put B&S "Experts" up against him anytime. I doubt you can adjust to .001", this is why B&S gives a range. The Exhaust Valve train must have room for the components to expand with heat. My guess is that the Exhaust Valve is not closing completely when hot. Continue doing this will result in burnt valve and or seat. The Aluminum Push Rod goes on the bottom Rocker Arm, the Intake Valve.

The Exhaust Valve has absolutely nothing to do with ease of starting as the Compression Release works off the Intake Valve.

You say you used Loc-tite, where? I suspect the Rocker Arm Studs are loose where they thread into the head resulting in the need to continually adjust, that is where you need to use Loc-tite.

Walt Conner

Thanks Walt. That is exactly where I used the thread lock. What would you suggest? Diassembling the valves to see if they have been destroyed? Or, should I just set the lash again to see if she will run? Sorry for my ignorance -- I am just trying to wade through this and lack experience.

I wonder if you have a cam shaft going flat?

While putting myself through college - I was a machinist for 6 years ... I can tell you that generic threadlock/loctite is not going to help your specific application (no chance at all)

threadlock/loctite comes in several strengths - and in my line of work we mostly used the strongest formula... Its very difficult to break free once it has set up ...

However the secret to loosening up any strength of this stuff is to simply apply heat to it... Once its hot it will turn back into a liquid and and can be loosened as if it was never applied to the area.

in addition - it does not tend to perform well in greasy/oily environments. unless the area has been thoroughly cleaned with something like a lacquer thinner (and sealed) afterwards. we used to apply silicon over the surfaces but eventually the harsh environments pulled the silicon off and the hot lubes would work their way into the screws and slowly break the stuff down... We found that in Dry/dirty/dusty conditions - the stuff worked great...

In your case - i assure you its being washed away into your oil... I wonder if it has caused any damage (probably not - unless you used it liberally) ... But there is no way thread-loc is going to work well since you are using it in a high temperature / oily region of your motor.

Good luck to you.

"In your case - i assure you its being washed away into your oil."

Well I pretty much doubt that and I can give you some reasons if need be but I can see the point about the heat perhaps softening it. This was a idea put forth sometime ago by someone else that I adapted thinking it might help. Incidentally several people report having used it and not had a further problem with the studs loosening.

"What would you suggest? Diassembling the valves to see if they have been destroyed?"

I wrote a length response to this but for some reason, it didn't make the list. It went something like this.

There is a correct way to adjust the valves.IF you are absolutely sure you have been adjusting the valves properly, correctly, then perhaps you should pull the head off and see what is going on with the valves and valve seats.

There are a couple of things yet that I have questions about. When you adjust the valves, where and to what spec. are you torquing the locking mechanism?

"I continually need to readjust after each time I mow even though i do use thread lock."

What are you saying here? You said you were using Loc-tite on the Rocker Arm Studs where they go into the head. Are you saying that they are loose each time? IF so, to what spec. are you torquing them?

Walt Conner

Oh yah, Had this in the original post but forgot it in re-try. Like Bill says, it might be the camshaft. Some Camshafts for these engines were not properly hardened and the lobes wore off prematurely. This should be easy enough to check, remove the valve cover and check the operation of rocker arms and valves. They should both have about the same amount of motion.

Walt Conner

I did not use a torque wrench when i tightened the locking nuts one the rocker arm studs. Rather, i used the "hand tight" method -- meaning I tried not to over tighten for fear of stripping. Again, I am no expert. I have been using online B&S manuals, forms, etc. to weed through this.
Since the incident, I have done nothing to the engine. I pushed it to the garage and I am waiting for the weekend to dedicate some time to it. Should I readjust the valves to the manufacturer's specs and try turnig it it over. I will make sure that the rocker arms are moving per your suggestion obviously. But, I do not want to damage anything further by trying to start it.

Thanks again.

You did not say where you were getting the play, the rocker arm studs coming loose, they need torqued to 85 inch lbs, or the rocker arm adjusters, they are torqued to 45 inch lbs. And by the way, you adjust the clearance, run up the nut, hold the nut, torque the torx head screw. Rechecking after tightening. Clearance is set with the piston 1/4" down from top of cylinder past TDC. Today's engines are more particular than old ones and a torque wrench is almost a necessity to do it right.

Walt Conner