# Briggs 42A707 carb flooding.



## Chris86 (Jun 8, 2013)

I was recently given a Craftsman LT2000 hydro with a blown engine. I found an old MTD with a Briggs 42A707-1237 opposed twin and got that engine and put it on the LT2000.

I should mention that this tractor has a gravity feed gas tank and now an engine with a fuel pump..

I was having some issues with it running weird and flooding so I bought the whole carb/fuel pump rebuild kit and after rebuilding the carb and fuel pump I'm still having problems.

The problem I'm having is flooding.. I think. I can crank it up after it has been sitting for a few hours and it will run fine, but if I turn it off and try to start up again within a few minutes, it will be flooded. I have to drain the bowl and dry the spark plugs, then wait several more minutes before it will fire up again.

My uncle has been helping me with this project and he suggested that the problem could be caused by the gas feeding by gravity into the pump. We tested that idea by connecting it to another fuel tank that we could hold close to the ground and got the same result.

So I have a couple of questions. Why is it flooding, and will it be alright with the gravity feed tank?


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## Chris86 (Jun 8, 2013)

Does anyone have any idea what's going on with this engine? I've been using this mower to cut my neighbors grass so I need it running correctly ASAP.


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## Chris86 (Jun 8, 2013)

UPDATE: My uncle and I re-checked the fuel pump to make sure it was put together correctly. We also lowered the gas tank thinking the gravity feed still might be part of the problem. The engine started just fine several times until I put the air filter back on.. then it flooded again..

Any ideas or suggestions would be greatly appreciated.


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## DaveBiz (Jun 5, 2013)

If it is running fine without the airfilter but not with it, then I would suspect a problem with the airfilter. Did you replace it? Is it clean? If it is restricting airflow, the engine will run rich and cause the flooding condition.


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## Chris86 (Jun 8, 2013)

Hi Dave. 

The air filter is brand new and squeaky clean. When the engine is running it runs just fine with or without the filter. It just seems that when we think we've got it fixed and we put it back together and all the tools are put up, then it's not going to start. Maybe now we just need to adjust the mixture with the air filter on?

As I said earlier, if I wait a few hours or a day before trying to crank it, it'll fire right up, but if I turn it off or if it runs out of fuel and I try to crank it up again while it's warm it will not fire up no matter what position the throttle or choke is in, and no matter if the air filter is on or off most of the time. I've checked the coil and plugs and they're doing what they're supposed to.. so no problem there.

So I had pretty much just come to the conclusion that I would just not turn it off until I was done with it for the day, but then I start using it this morning pulling a small trailer to haul off some brush and I stop to dump the trailer and idle the engine down and it cut off on me. It didn't cut off like the idle was set too low, it cut off like I had turned the switch off. So I put it back to full throttle and cranked it again, it fired up for about 3 seconds then cut off again and wouldn't start up anymore.

This thing makes me want to pull out what little hair I have left!
I'm really starting to consider finding another engine for this mower, but that will be an absolute last resort.


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## Chris86 (Jun 8, 2013)

UPDATE: 

I think the problem has finally been diagnosed and it's nothing to do with fuel or the carburetor... it's the coil.

It starts right up when it's cold because the coil isn't hot, and while it's running the air blown from the flywheel keeps it cool enough to run, but when the engine is turned off while hot it heats up the coil and causes it to not fire.


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