Well - I'm Back!!

Darryl G said:

Seems you're still left with all of the same possibilities; ignition and valve timing out of sync or mixture too lean. Is it possible that your valve adjustment method is improper? I know you've done it multiple times, but what if you're doing it wrong?

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From my past experience with this engine.... there's no doubt in my mind that the valve settings could be the culprit. Before, it was about doing the settings 1/4" past top dead center.... to facilitate the compression release system which uses a small lobe on the cam shaft to release some pressure through the intake valve. I've tried to check and re-check the settings with no luck.

One other thing still concerns me with this engine. The intake manifold "elbow" .... where the manifold meets the engine head. It's not clear to me... and I've looked at every source I can find... why there would be what B&S calls a "Intake Restrictor" plate. That plate was installed when I bought the mower... and it ran fine. During a rebuild.... when I bought and installed a new Niki replacement carb.... it wasn't clear to me how (or if) it should be installed. The plate is a thin polished metal disc which would make sense... since the elbow uses a o-ring to mate with the head. But what gasket (if any) mates between the metal "disc" and the head itself. It appears like there may have been some sort of fiber gasket backing on that plate.... that is either missing or perhaps worn off. I'm going to order a new "restriction plate" to find out. I've tried using a regular carb gasket along with the plate.... without success.

I've never understood why they would use a restriction plate that basically limits the intake by half.... it's cut out like a half circle .... and installs (best I can tell from drawings) with the opening at the top. And.... of course.... the more you mess with the o-ring during installation... the more likely it becomes worn and causes a potential leak. Right now, that's at the top of my list of potential causes.

The only other thing I can think of is that the severe damage (shock) that the flywheel had (see the earlier picture) may have actually been powerful enough to bend or otherwise compromise the crankshaft somehow. I'm trying not to dwell on that idea!

Thanks for the interest. I will be checking the valves AGAIN tomorrow.... and see if I missed something there.

Bill

Bill,
The restrictor plate is there to reduce the Hp of the engine, that is all it does.
One of the way engine companies manage to get 6 to 10 different Hp ratings from a series of engines with the same bore, stroke & running rpms.
Some times you can remove it some times you have to put in a bigger main jet if you remove it.
Governed engines are a touch different to throttle control engines like your car where you can run too lean & blow the engine.

If you are worried about the seal spray some WD 40 ( or similar ) FROM A TRIGGER PACK all around the manifold while the engine is running.
WD 40 burning will cause thick whit smoke and the revs to change if it is getting sucked into the engine by an air leak.

I've worked long and hard.... rebuilt the entire mower..... here's the reward for my work. Ain't she a beauty now?

(CLICK PHOTO TO ENLARGE)