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runs then stops

Yardman's Avatar
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07-01-03, 05:45 PM   #1  
runs then stops


I have read and followed several postings. I have a B & S 6.25 HP self-propelled mower. Model # 12A-526L062. Serial # 1B122K30708. I have replaced the air filter, cleaned the carb and the little screw(The Carb is clean as a whistle.), tested the fuel line(fuel runs well into the bowl), and checked the float operation(works). Yes, it has gas(fresh) and oil(learned that a few years back)

The mower is 1year old. Runs for about 15sec then shuts down and will not start back until several hours later. Could the automatic choke not be working???? I assume it has an automatic choke since I don't have to adjust any thing. I have not changed the plug because it cranks with only 1 to 2 pulls in the beginning. Also the mower would surge and slow way down and not keep a constant speed prior to it stopping for good. Don't know if this is related.

I am in luck with the rain coming gives me a chance to fix it before the neighbors complain. Thank for you help!!!!!!!!!!!!

Last edited by Yardman; 07-01-03 at 06:10 PM.
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07-01-03, 07:41 PM   #2  
Hello Yardman. Welcome to our Do-It-Yourself Web Site and our Small Engine forum.

Before attempting any repairs, try this first. Run the engine without the fuel tanks cap on. If the engine runs normally and continuously, the vent hole on the gas cap is restricted or plugged.

If the same condition exists, vapor lock may be the cause, a restricted fuel line or filter, or some other reason fuel may not be getting to the carb. check fuel flow out of the tank.

Change the spark plug. Possible it is getting grounded out internally. A new plug may solve the problem.

Most likely I haven't covered all of the potential possibilities. The other resident small engine service and repair professionals may offer additional suggestions, advice & help.

Check back on your question several times over the next few days for additional replies.

If you need further assistance, use the REPLY button. Using the reply button moves the topic back up to the top of the daily topic list automatically & keeps all communications in this one thread.

Regards & Good Luck.
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07-01-03, 11:38 PM   #3  
Gotta go with Sharp Advice here Yardman...still sounds like a fuel problem. Try it with the fuel cap off as suggested, but I think the problem is still in the carb. The surging points to a fuel problem almost for sure. Does it puff black smoke?

One thing I have seen many times on this engine design is the carb mounting bracket gets loose because one of the bracket-to-engine bolts breaks. This would allow the engine to run lean. Try wiggling the carb, if you can, then that is part or all of the problem.

I also agree that you should start with a new plug...even though it starts fine, it still can cause problems if it is going bad. Plugs can do funny things.

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07-02-03, 01:58 PM   #4  
Hi yardman!

Just stopped over to say hi - we are neighbors - I am in Chesapeake! (also had some mower problems - now fixed tho - I think.)

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07-02-03, 02:00 PM   #5  
Thanks I will go and try these as soon as it stops raining.

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07-02-03, 02:22 PM   #6  
it apppears fixed

It looks like it was the plug. Weird that it would still start when cold and not keep going. The flow through the fuel line is great.

Hi yardnut. Don't you just love this rain. Kills the fishing for the next couple of days. Got to get me a cobia this year.

Again thank you for the advice. Next time I'll just change the plug, oil and filter before tearing out the carb. Breaking it free was a
b*(^% from the manufacture tightness on the bolts.



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07-02-03, 02:31 PM   #7  
Hi: Chris

Glad you found the cause of the problem. A spark plug is always a possiblity when the conditions you described occur. Also one of the simple parts to cause the problem and one of those which often gets overlooked.

Thanks for posting back the final results that fixed the problem. Doing so allows all the readers of your question to learn more...

Regards and Good Luck.
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