5 HP Briggs and Stratton problem?
Why would the idle on a 5hp briggs cut down randomly for about 5-15 seconds and them idle back up after that? The carb is new and looks fine. The plug, air filter and oil are all changed and good. Fuel level does not make a difference. I don't see any leaks. It's not smoking that I saw. What are your thoughts?
Update:I don't think that there is water in it. It doesn't idle up and down constantly like if there was water in it. I'll be mowing then it sounds like it is going to die but then the idle just cuts down. it stays like that for a few seconds then the idle goes back up to normal. Over 20 minutes could go by before it would do it again. Or just a minute or 2 may go by before it does it again. It is really random.
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The membrane in the gas pump do not work properly when you start the machine. Clean up the gas filter and the membrane in the pump. It will be ok.
First the small B&S engines are gravity feed no fuel pumps!
Second this is a fuel problem or a governor problem. Lub the governor and throttle linkage with motor oil, next loosen the gas cap 2 turns and try it again. If that solves the problem, clean the cap vent. If not then I would look for a physical bind on the cutting blade like the grass is too tall and it is lugged down. Take smaller cut widths.
This could be an issue with the governor or linkages. Also if this engine has a tank mounted carburetor, it may be the diaphragm between the carb and the tank needs to be replaced. I have included a link below that will help you check the governor and the linkages.
Best fuel problem solver I've ever used is Berryman's B12 Chemtool in liquid or spray. Find it at Walmart or your favorite auto parts store. Great for cleaning/removing water, sludge, varnish and more from fuel systems. I add it to my 5 galon gasoline can and sometimes add a teaspoon quantity to my mower and tiller tanks.
If the ignition coil isn't the priority than you very almost would desire to lean in the direction of gas. Does that engine have a gas close off solenoid on the backside of the carburetor? perhaps you will desire to verify it somewhat is operation whilst warm. If it does not open the engine won't run. Coils tend to fail whilst warm and artwork whilst cooled down making them confusing to diagnose. in basic terms a theory.