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AnsweredHot!Backfire through the Carburetor.

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Bigglesaircraft
Bigglesaircraft
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2019/04/06 14:21:07 (permalink)
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Backfire through the Carburetor.

I have a B&S 310000 engine in a McCulloch Ride on Mower. The other day while using the mower the engine suddenly stopped, no noise no indication before that anything was wrong. I tried to restart the engine, it turn over OK on the starter but did not start but backfired through the carburetor/air cleaner. It seemed to me that somehow it had either suddenly developed a timing fault or possibly a problem with the inlet valve. Any one to offer me some help before I decide to do a complete engine dismantle.
Bigglesaircraft
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Re: Backfire through the Carburetor. 2019/04/07 14:59:39 (permalink)
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Bigglesaircraft
I have a B&S 310000 engine in a McCulloch Ride on Mower. The other day while using the mower the engine suddenly stopped, no noise no indication before that anything was wrong. I tried to restart the engine, it turn over OK on the starter but did not start but backfired through the carburetor/air cleaner. It seemed to me that somehow it had either suddenly developed a timing fault or possibly a problem with the inlet valve. Any one to offer me some help before I decide to do a complete engine dismantle.


As I was getting no suggestions or answers I decided to investigate my problem by taking the engine apart. I started at the Flywheel as the key can be a source of trouble with misfires and backfires as it affects the timing. I found the key to be fine and in its correct position. So, as the backfire was coming through the carb I decide to look at the valves, after removing the rocker cover I noticed that the inlet valve rocker was extremely loose and only just operating the valve. So once adjusted and all parts replaced the engine started fine and therefore the problem solved.
The mower had been serviced only 3 weeks ago so I guess that the person doing the work did not tighten the inner rocker locking screw.
 
I think I will do my own servicing from now on.
AVB
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Re: Backfire through the Carburetor. 2019/04/07 19:48:50 (permalink) ☼ Best Answerby Bigglesaircraft 2019/04/09 14:01:39
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Sorry you think we are too slow but personally I run my own shop and am the chief cook and bottle washer soon I do get tied up at times. I also take Sundays off for the most as I work 6 day a weeks putting 10-12 hr days.
 
As the backfire out of the carburetor it is plausible that it was the exhaust valve that was giving the problem. And it is normal for the valves to get a lot clearance on OHV engines. With Briggs RTVing these covers on many inexperience techs avoid pulling these as they are hard to seal unless you the exact instructions of the RTV.  24 hrs before starting the engine is a must or they will leak with a few months.
Bigglesaircraft
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Re: Backfire through the Carburetor. 2019/04/08 10:39:17 (permalink)
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I am very sorry if I have caused any offence with what you may see as my very discourteous, rude and impatient  reply.
 
 I apologize to you and the other Forum users.
 
I was in a very frustrating dilemma and required some really quick answers before I attempted a complete engine strip down and order the necessary parts to arrive for monday or tuesday.
 
 
I am a regular user of a motorcycle UK Forum and generally people start to reply before you can finish posting your query, well slight exaggeration, so rather unfairly I was expecting the same.
 
Again please accept my apologies and if I correspond on the Forum again I will endeavor to be polite, courteous and constructive.
post edited by Bigglesaircraft - 2019/04/08 10:45:14
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