Those (Christmas Tree Lights) have worked fine for me for the last 40 years and only. $12.00. Todays coils are not like those used will point/condenser ignition systems. If you are doing this as a business, then “maybe” you can justify purchasing an expensive tester, but for the DIY guy really doesn’t pay. Truthfully I can’t remember the last time I ran into a coil which was producing a “weak“ spark. If you really think you have a weak spark run this test. Gap a new, good plug to .150” and install in the cylinder. Install an inline tester and check for spark. Spark at .030” and no spark at .150” means weak coil. Cost to you, less than $15.00. I’d rather purchase a light bulb fluid tester or wire stretcher.
Old 8hp Briggs and Stratton stalls regularly
- Thread starter gpburdell
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Fish
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After reading the last posts, I am leaning toward valve lash. With that engine on that model, it is even more complicated. Removing and installing those valves can be tricky without the right tools. But I would take a peek under the head gasket, your engine could be badly worn, and a proper valve job would make it smoke like a freight train.
Take off the head, and take some pics.
Take off the head, and take some pics.
Fish
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I would wait until after pulling the head, before ordering parts.
Snap On or Harbor Freight take your pick. I like to see what the coil can and can't do.
Fish
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The older engines had a metal/asbestos clad gasket, which I have been know to reuse. I would wait until you know the condition of your engine before buying anything.
Have you replaced the spark plug?
Also you need to blow back through the fuel hose with the gas cap off.
Some of them old Briggs had a very fine screen inside the gas tank.
Some came out with the petcock and some did not. They will run for little while and shut down. (and re-start almost immediately, but the engine will usually not just quit fast it will hunt and surge first.
Also try running the engine with the kill wire off. Disconnected at the Magneto.
I suspect you are wasting time removing the head. Carbon buildup would not cause your DESCRIBED issue unless a piece got hung in the spark plug gap and that is not likely to be an intermittent thing as you describe.
Loose carbon would go out the exhaust port.
You really need to be careful with the TWO HEAD bolts that are by the exhaust port. They can twist off easily if you do not know how to pre-loosen them easily by doing the gentle rap shock to their head. The exhaust gets them hot and galls/seizes the threads in place.
Also you need to blow back through the fuel hose with the gas cap off.
Some of them old Briggs had a very fine screen inside the gas tank.
Some came out with the petcock and some did not. They will run for little while and shut down. (and re-start almost immediately, but the engine will usually not just quit fast it will hunt and surge first.
Also try running the engine with the kill wire off. Disconnected at the Magneto.
I suspect you are wasting time removing the head. Carbon buildup would not cause your DESCRIBED issue unless a piece got hung in the spark plug gap and that is not likely to be an intermittent thing as you describe.
Loose carbon would go out the exhaust port.
You really need to be careful with the TWO HEAD bolts that are by the exhaust port. They can twist off easily if you do not know how to pre-loosen them easily by doing the gentle rap shock to their head. The exhaust gets them hot and galls/seizes the threads in place.
Thanks, I'll try blowing back through the gas tank. My mower is an old Snapper riding mower that has a black plastic gas tank where I can't see the inside the tank because of how it's curved. It could have a screen in it, I'll see if I can find a borescope to peer inside with. Thanks for the tip on the exhaust bolts. I agree that is unlikely the problem but thought it might be a good idea to clean it out. I noticed in the manual it even says to remove the head periodically and clean it out, though I've never done it before. I'll also see if I can disconnect the kill wire right at the magneto.