# Engine missing



## enigma-2 (Aug 16, 2012)

This started last fall, but didn't think much of it. When I started the Simplicity this spring, it started hard (been sitting in the shed with old gas - used Ethanol treatment). 

Anyway, started and had to immediately take choke off, running at high speed misses and pops. Exhaust smelled funny, burned the eyes, like running too rich.

Now, if I reduce the speed jussssst slightly (and all the way down to idle), it runs smooth and sweet. Or if I run it wide open and engage the mower deck, smooths right out and runs fine. 

I'm pretty certain it's the carb that either got some dirt in it or gummed up, and I added a fair amount of SeaFoam AND MMO, mowed the entire yard but haven't started it since Friday and don't know yet if that had any effect. (I find it usually has to set a spell to dissolve the gum).

Wondering if there is a circuit in these carbs that only is effected at full, top speed? (And even then, why would it smooth out at full speed when under load?)

Anyone have any ideas?

26 hp Briggs Pro engine, mid-grade gas (with Ethanol), Regency less than a year old. Dealer serviced last summer after 5 hours and cleaned carb, was running fine until around mid September when the problem started; it was put away for the winter shortly thereafter.


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## jhngardner367 (Apr 5, 2011)

There should be a high-speed adjustment on it. post the engine #s,and we can find out.


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## ftorleans1 (Jul 12, 2009)

Sounds like your high speed circuit is feeding too much fuel. It will smooth out when you engage the deck because the engine is being put under a load so therefore it needs more fuel to keep running. The old Briggs Twin II engines would suffer this with the carb design they had. The engine would lope until enough load was applied then it would smooth out. You might want to siphon the possible bad fuel from your tank and try with fresh fuel.


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## Country Boy (Mar 18, 2010)

Had a Simplicity with a Briggs run rich last summer. Finally traced the problem to the wrong air filter being installed. Some have a deeper air filter that allows more air through, and he had the thinner air filter with shorter pleats that was acting like a mild choke on the unit. It would run great with the air filter off and sputter a bit with it on. Swapped to the correct air filter and the problem went away.


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## enigma-2 (Aug 16, 2012)

Follow up. Did a standard cleaning, but still had problems. Had the local dealer run the carb though his ultrasonic carb cleaner. That fixed it, running like new now.

Been using mid grade, dealer recommended I go to high test for this engine (CARB compliant) and the particular station where I buy my gas (Marathon). His reckoning is, these new carbs have much smaller ports that clog quicker. Also recommended I switch from StaBol Ethanol to SeaFoam (which I was also using). 

He also told me which gas stations in the area to avoid. 

Dirty gas and/or too much Ethanol, judging from the number of ruined engines he's sees from certain brands of gasoline. (He thinks that certain stations are not advertising it, but are using more then 10% Ethanol, as a profit increaser, because he sees not just valves burnt, but pistons burned through as well).


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