Cast iron briggs issues

My old cast iron Briggs and stratton 320424 14 horsepower horizontal shaft has been acting up lately. It takes forever to start and when it does I have to hold it at idle until it goes to the right idle speed. I can then slowly let it throttle up and it will run pretty good after that. But if the engine even does so much as try to go above half throttle the engine slows way down and barely runs at all. It just sputters and occasionally fires to stay running. The carb is brand new and is in good shape. So the only issues I think this could be are ignition related (it does have points) or the issue is an out of adjustment carburetor. I am not familiar with these old briggs as I normally work on old Kohler K series. So any help such as carb tuning procedures would be greatly appreciated.
 
Go to the electronic ignition, l use the nova11 for my 243431 cast iron 10hp
simplicity landlord. Best think I could of done, beats adjusting & cleaning points
all the time.
 
I would start with a new coil, and electronic ignition, unless you need it original, then replace the points.

I think that model has a phenolic plunger that operates the points. If so, pull it out, clean and oil it. (Only if keeping the points.)

Is the main jet adjustable on the carb? If so adjust it so the engine will take sudden throttle from idle without stumbling. Turn it in until it stumbles, then back out 1/4 turn at a time until it takes throttle smoothly. Do this after you're happy with the ignition, valve lash, no vacuum leaks, clean air filter...
 
I dont thik that a vacuum leak or the valves are causing this because it runs great once it has revved up. It lest can't go above half throttle. But I have not dealt with a flathead with valve issues so I will check the lash when I get home today.
 
(quoted from post at 08:03:55 05/23/19) I would start with a new coil, and electronic ignition, unless you need it original, then replace the points.

I think that model has a phenolic plunger that operates the points. If so, pull it out, clean and oil it. (Only if keeping the points.)

Is the main jet adjustable on the carb? If so adjust it so the engine will take sudden throttle from idle without stumbling. Turn it in until it stumbles, then back out 1/4 turn at a time until it takes throttle smoothly. Do this after you're happy with the ignition, valve lash, no vacuum leaks, clean air filter...

Thats exactly what I have thought is the issue. Dirty points, out of adjustment carb. That'll do it for sure.
 
Oh and does anyone know what the valve lash would be? I went to brigg's website and they won't even admit making the engine. Let alone telling me the valve lash.
 
(quoted from post at 11:07:38 05/23/19) Oh and does anyone know what the valve lash would be? I went to brigg's website and they won't even admit making the engine. Let alone telling me the valve lash.

ThhbuCs.jpg


Your engine is "320000 series", your info is on the bottom line of the chart.
 
I just got done with re lapping the valves in and boy were they off. exhaust was at .1 and intake .055. I had to grind a bit off the back, and re surface both of the valves in my lathe. So I finished thinking it was just gonna start and run perfect. And of course the problem didn't change at all :evil:
 
I can not conceive how you could get .100" valve lash (exhaust) and .055" (intake) on an engine that was running properly before. ...Certainly, those clearances would affect valve timing, which will affect starting and running.

Those clearances could not happen from wear, but may be indicative of loose valve seats.
 

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