14 hp B&S stops running after 1 hour

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Old 05-19-07, 04:57 AM
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14 hp B&S stops running after 1 hour

I have a 7100 series (1980s vintage) Simplicity tractor with a 14 hp B&S engine. The engine runs strong for about 1 to 1 hours then it starts to loose power as if it is starving for gas or air. It then stops running completly. It starts up again after it cools for about 1 hour, and then repeats the process. I had the carb rebuilt, new head gasket, new points and plug, along with all new throttle springs. I personally think it is a heat problem. Could it be the coil or a sticky valve that acts up after it runs for a while?
 
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Old 05-19-07, 06:07 AM
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Have you tried loosening the gas cap and see if it still quits after an hour? I'm wondering if you are slowly building a vacuum in the fuel tank that eventually starves the engine of fuel. Letting it sit for an hour lets air seep back into the tank and it runs fine.

I would think that everything on the engine should be up to full temp long before an hour so I'm not sure what would take that long to heat up and cause a problem.
 
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Old 05-19-07, 06:21 AM
Azis
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You mentioned having parts replaced, by who? (Shop, Tech, Mech buddy...yourself?)
It would be most useful if you can post the engine model and type. I have to wonder about the points...
1. If you have points on your engine?
2. If you do have points, and they were replaced, why, instead maybe of converting to a coil that would not require points be used.

Of course the fuel cap is always worth trying, its free quick and easy
 
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Old 05-19-07, 09:45 AM
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I'd recommend the fuel cap trick first, as well. So you don't splash any fuel out of the tank, be sure you have a half tank or so of fuel and run with the fuel cap loosened and see what happens. Yes, it could be ignition related or valve related, more likely to be ignition (coil) related though, of the two. Is the fuel system delivery gravity feed or fuel pump feed? Post back not only with the engine model and type numbers, as Az asked, but also the code number.
 
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Old 05-24-07, 07:00 AM
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14 hp B&S stops running after 1 hour

Actually, I purchased a new gas cap thinking that this may be the problem. I also insulated the gas line to eliminate a potential vacuum problem. But, I will loosen it and see what happens.

Thanks for the comment.
 
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Old 05-24-07, 07:06 AM
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14 hp B&S stops running after 1 hour

I had all the work done by a certified Simplicity and B&S dealer. The B&S is model number 326437, type 0315-01. I purchased the tractor new back in 1979 and this is the original engine. I have had no problems with it until now. I have been thinking of converting to an electronic ignition, thus eliminating the coil and points, but I need to make sure that this is the problem. If it is the valve, then I will get the engine rebuilt.
 
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Old 05-24-07, 07:11 AM
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14 hp B&S stops running after 1 hour

Thanks for your comment, the type is 326437, type is 0315-01, code is 7906271. The fuel system is gravity feed. I was thinking of a way to validate if it is a coil problem or a valve problem. The next time the engine cuts out I am going to pull the plug and see if there is a spark. I would assume that if there is no spark at this point, then it must be the coil. Do you think this will validate a coil problem?
 
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