Crafstman 247.25000 Riding Mower Stalls

ldefanti

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I have a 247.25000 Craftsman riding mower (951-12823 Carb Assembly) that starts, runs for about 30 minutes then acts like it is starving for fuel, stutter then stalls. Will restart after cooling off for fifteen minutes or so. Will run again for a while, then repeat. Checked plug at shutdown and checks OK, Put in new coil anyway (cheap insurance), drained and cleaned fuel tank and lines, added new fuel filter and fuel cut off switch, pulled carb, cleaned, cut off tip of fuel solenoid, drained oil, new oil and new oil filter. When it runs it has a very minor occasional stumble...can't tell if its gas related or plug even though plug is new and coil checks out fine and is installed correctly. Any suggestions from here? New carb time?
 

ldefanti

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Re: Craftsman 247.25000 RER 1000 Riding Mower Runs, stumble, small backfire

The saga continues......new carb, new coil, plug, changed oil and filter, set valves to .004 and .006, can throttle newly installed fuel cut off valve to reduce gas and engine seems to level off a lot. Light stumble then have to open valve to refill bowl....repeat. MTD motor 4P90JUA. Mfg says fuel problem.....no kidding. I have a small fortune in MTD parts in this beast....must be something simple....any ideas? Tighten or loosen valves? Carb #3? Unadjustable EPA carb or this problem likely would have been fixed by now. Not gas cap or roll over valve - checked them too. SEND HELP (Or parts)
 

ILENGINE

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Wondering about heat related issues at the carb, but it appears that the exhaust is a good ways from the carb, so not as likely as some other models. May consider intake manifold air leaking when hot.
 

ldefanti

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Re: Craftsman 247.25000 RER 1000 Riding Mower Runs, stumble, small backfire

The saga continues......new carb, new coil, plug, changed oil and filter, set valves to .004 and .006, can throttle newly installed fuel cut off valve to reduce gas and engine seems to level off a lot. Light stumble then have to open valve to refill bowl....repeat. MTD motor 4P90JUA. Mfg says fuel problem.....no kidding. I have a small fortune in MTD parts in this beast....must be something simple....any ideas? Tighten or loosen valves? Carb #3? Unadjustable EPA carb or this problem likely would have been fixed by now. Not gas cap or roll over valve - checked them too. SEND HELP (Or parts)
Also changed out the 2 carb gaskets and manifold gasket with self cut better material for sealing.......I think my next test will ne about 20 lb leak down test......obviously compression is ok as it starts and runs....any other ideas?
 

bertsmobile1

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Usually I would have recommended fitting an in line spark tester and watching it when the engine starts to play up.
A hang over form engineering training.
Watch look & listen first , then start to think then start checking and replace parts last.
in the morning before you start , remove the fuel line and crank the engine into a container for a fixed time.
mark the container.
When it is playing up, do the same test.
If it is significantly less you have a blockage in the fuel line or tank.
The landlord has 4 x 2000 series cubs which used to play up when hot.
All of them ended up being floating debris in the fuel tank
And this took a very long time and a lot of parts substitution to work out.
 

ldefanti

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Jun 22, 2017
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Usually I would have recommended fitting an in line spark tester and watching it when the engine starts to play up.
A hang over form engineering training.
Watch look & listen first , then start to think then start checking and replace parts last.
in the morning before you start , remove the fuel line and crank the engine into a container for a fixed time.
mark the container.
When it is playing up, do the same test.
If it is significantly less you have a blockage in the fuel line or tank.
The landlord has 4 x 2000 series cubs which used to play up when hot.
All of them ended up being floating debris in the fuel tank
And this took a very long time and a lot of parts substitution to work out.

EUREKA............today I checked valves....still .004 and .006, reinstalled old carb (cleaned), installed new Champion plug, filled cylinder with PB for small engines then installed plug. Checked choke setting and cable - OK.....pulled rollover valve - tested OK...........reassembled.......did gas run out test into filter to make sure the tank was working correctly with the cap on. Put gas back in. Moved outside, opened fuel cut off valve. Full choke, turned over three times blew out a cloud of smoke and started up running smooth. (First time in over a month) Mowed back yard like a champ and never sputtered or quit even when hot....so far. It is 96F here today. As I gave gone this far I am going for a new blade tomorrow and mow like mad. I'll update only if I have problems.
 
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