Briggs 42a707 no start troubleshooting.

T

TJWerner

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I just picked up an older (1998 or so) MTD Yard Machines riding mower with the 2 cylinder Briggs and Stratton 42a707 engine.

The engine was not running when I bought it, but I was told that it was running recently -- I bought it off a kid who was going to convert it to an 'off road' mower. I'm more interested in mowing my lawn with it than off roading, but that's another story.

Anyway, it supposedly ran within the past year. The engine turns with the key but will not fire up. I confirmed spark with a spark tester. Replaced plugs with Champion RJ19LM, which supposedly cross referenced to the Briggs spark plug for this engine.

I've tried firing it up by spraying starter fluid into the carb, but no go. My thought is, if I can get it to fire up with the starter fluid, then I'll do a carb / fuel pump rebuild and have a good running mower come spring time.

What am I missing? What other diagnostics are needed? Would removing the carb and spraying starter fluid in the manifold work? Again, I just want it to fire up, then I'll work on the fuel issues.

Thanks,

Tom
 
reddragon

reddragon

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at least take the carb apart and clean every thing and clear out all the passages....then use fresh fuel and starting fluid to try it out again
 
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TJWerner

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Thanks.

Is starting fluid strong enough to allow ignition on its own, or does it need some gas to help things go boom.

And, can I pour some gas into the carb to get things to fire up initially.

Tom
 
reddragon

reddragon

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starting fluid is more explosive.....getting rebuild kit wouldnt hurt either.....they're only bout $22
 
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wcpost

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Look on the bottom of the carb. There might be a solenoid that requires voltage to open and allow fuel to flow to the carb. These are there to stop fuel when the engine is cut off to prevent backfires.
 
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ramit

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i don't know but this is exactly the problem that i am having with my 42a707 motor.

TJWerner said:
I just picked up an older (1998 or so) MTD Yard Machines riding mower with the 2 cylinder Briggs and Stratton 42a707 engine.

The engine was not running when I bought it, but I was told that it was running recently -- I bought it off a kid who was going to convert it to an 'off road' mower. I'm more interested in mowing my lawn with it than off roading, but that's another story.

Anyway, it supposedly ran within the past year. The engine turns with the key but will not fire up. I confirmed spark with a spark tester. Replaced plugs with Champion RJ19LM, which supposedly cross referenced to the Briggs spark plug for this engine.

I've tried firing it up by spraying starter fluid into the carb, but no go. My thought is, if I can get it to fire up with the starter fluid, then I'll do a carb / fuel pump rebuild and have a good running mower come spring time.

What am I missing? What other diagnostics are needed? Would removing the carb and spraying starter fluid in the manifold work? Again, I just want it to fire up, then I'll work on the fuel issues.

Thanks,
Tom
Click to expand...


i have cleaned the carb and am at least getting gas to the cylinder now. i am getting a white spark from the spark plugs. however the only way it will even try to fire up is by spraying ether directly into the spark plug holes.
i was using it 2 weeks ago when it stalled and will not restart.
im considering the head gaskets now due to the oil all over under the hood.
 
tom3

tom3

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One thing I do for this kind of troubleshooting is to blow into the gas tank. Get a decent seal and pressurize the tank enough to push gas through the filter, pump, and fill the carb. Helps to pinpoint the problem, sometimes fixes it too. Have to be pretty macho to do this, or just dumb like me.
 
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