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B&S 7hp won't start


geogrubb's Avatar
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07-16-07, 04:19 PM   #1  
B&S 7hp won't start

I sold a lady(everyone's thin frail aunt)a used mower for $50 and as I started to put it in her van she already had a mower in there, she asked if I could use it for parts, that a lawnmower shop told her it had a bad upper bearing, that it must have been ran without oil and was not worth fixing and she should buy a new mower, she didn't. I alway remove the covers and powerwash them before I do anything, this mower has/had not been apart past the plastic covers, no play or clatter or clunk of any kind. On a flat head I spray some starter fluid in them and give them a pull to see if they fire. It's a Craftsman 917.378980 - sn 062404M 003780
Has a : B&S 128602 - 0304 - 04616 FB
OK guys what do I need to do different on a OHV. Thanks and have a good one. Geo

 
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07-16-07, 07:04 PM   #2  
Are you saying it won't fire with a cheat prime in the carburetor throat? And you're looking for advice for where to start looking? If so, does it have spark at the spark plug and, if so, strong enough? Does it have sufficient compression? Is the intake manifold OK (not loose/broken)?

 
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07-16-07, 10:10 PM   #3  
It has good compression, I haven't measured it but it seems good, I thought the spark was weak and set the mag to a tight .012 with brass feeler guage, turning it with one hand while holding the plug wire it gives a nice tickle. I will do my normal stuff and if it doesn't work I will ask more questions, I just didn't want to chase a problem that may not exist, like I should have checked the valve clearance or removed the valve cover to check for an indication the engine was ran without oil. Thanks, and have a good one. Geo

 
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07-17-07, 02:01 AM   #4  
Will the engine not start? Even with the cheat prime?

 
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07-17-07, 08:31 AM   #5  
It will not start, not even a poof, I think maybe the spark is not strong enough. Is there a way to test the armature/magneto? Have a good one. Geo

 
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07-17-07, 03:40 PM   #6  
Problem solved:
The rocker arm retainer had backed off to the point the piece the rocker rides on had fallen off the intake valve. The first clue was when I held my thumb on the sparkplug hole , turned the engine and it tried to suck my thumb into the cylinder. Anyway, I adjusted the valves to .006 put it back together and it started 2nd pull. Thanks puey for the advice and have a good one. Geo

 
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07-17-07, 06:15 PM   #7  
Yipee, thanks for the update, and, for future reference, you should purchase an inline spark tester (both Briggs and Tecumseh offer good, inexpensive ones) for testing ignition strength. This can be setup with the spark plug installed to run the engine and inspect for intermittent issues or without the spark plug to merely check for spark strength, period.

 
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