Briggs Twin 18 I/C Opposed Twin

IA Roy · May 27, 2017

Model 422437. Type 105001 Code 87110312 or 81100312. Not sure on the 2nd code number. This engine is in a Snapper garden tractor. It idles fine. When coming off idle it misses, sputters, and tries to die. I have it running, but not right. I need to play with the choke too much. I can only find one mixture screw. It is under the back side. It doesn't seem to do much when adjusted. This has a vacuum pulsation fuel pump. The pump appears to be part of the carburetor. I had it apart last year and cleaned all the inside and passages. Is there a way to check the pump to see if it is doing what it should? It must go directly into the bowl. Any links to this carb for diagrams or trouble shooting? I was told that the engine numbers told what the manufacture year was. What do the numbers tell you? Thanks to all in advance. I will give you feedback.

JF in MI · May 27, 2017

I have one (or at least nearly the same) and as I remember the mixture adjustment is only for the idle. It has a separate fixed main jet and yours may be plugged. Mine was built before gasahol and I had to drill out the main jet to get an extra 10% fuel to get it to run right.

IA Roy · May 27, 2017

I ran out of gas last night while tinkering. maybe the pump isn't working as it should. Filled it this morning and it is running a lot better. The gas is about as high as the carb when the tank is full. I also added a little seafoam. I will mow when I get the storm damage cleaned up and see how it does. 2 weeks since mowed and it will be a workout. Thanks.

Duner Wi · May 27, 2017

42 is about the cubic inch,
81 or 87 is the year built.
There is lots more info there too.
I thought they had adjustable main jet till 97 or 98.

Briggs Twin 18 I/C Opposed Twin

IA Roy

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JF in MI

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IA Roy

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Duner Wi

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