[turtlemower670]

I have a 16 yr old mower, its a MTD-Briggs & Sratton 650 series with the auto choke.
I have replaced the filter, changed oil, replaced the carburetor with a new one ( same type as the one it had on). I have replaced spark plug, checked kill switch wire(tested it) and tested the coil. Everything seems in good order. I am still not getting a spark. The flywheel looks in good condition and the mechanism for the pull string all work well. PLEASE can someone help me decipher this cruel and unusual joke my lawnmower is playing with me.:tango_face_crying:

 

[tomlct]

Just a suggestion here - The B&S 650 series mower engines would be the 650EX and 650EXi engines, I guess - the OHV engines. My Snapper mower has a B&S 675 series, which is an older flathead design, but I think the 650's would be OHV engines. Have you checked the valve clearance? I think that would be 1 more thing that could hurt how well it starts & runs. This article is a how-to, but I don't know the exact specs for your engine. If you do remove the valve cover and check them, you would want to know the specs. https://www.small-engine-projects.com/briggs-ohv-valve-adjustment.htm

 

[Grunt]

Welcome to MLF turtle.Just to be sure, I would try another spark plug, new doesn't necessarily mean good.

If your sure no spark is the problem, I would remove the engine cover and pull the kill switch wire OFF of the coil to eliminate a short as the problem.

On some engines the coil can be installed upside down and will not create spark, just a thought. Did you use a business card to gap the coil to the flywheel?

How did you check the coil? That may be the problem.

 

[turtlemower670]

Just a suggestion here - The B&S 650 series mower engines would be the 650EX and 650EXi engines, I guess - the OHV engines. My Snapper mower has a B&S 675 series, which is an older flathead design, but I think the 650's would be OHV engines. Have you checked the valve clearance? I think that would be 1 more thing that could hurt how well it starts & runs. This article is a how-to, but I don't know the exact specs for your engine. If you do remove the valve cover and check them, you would want to know the specs. Briggs OHV Valve Adjustment

Thanks tomlct, I will look this up. It is interesting how you brought this up, when I first opened the air filter i noticed the small choke had been removed. I later found it in the air filter, but no sign of the small throttle screw that holds it in. I am worried it ended inside the engine.

 

[turtlemower670]

Welcome to MLF turtle.Just to be sure, I would try another spark plug, new doesn't necessarily mean good.

If your sure no spark is the problem, I would remove the engine cover and pull the kill switch wire OFF of the coil to eliminate a short as the problem.

On some engines the coil can be installed upside down and will not create spark, just a thought. Did you use a business card to gap the coil to the flywheel?

How did you check the coil? That may be the problem.

Thanks Grunt for your reply, I checked the coil with out uninstalling it. I kept the coil in place and used my multi meter, it registered 4.75 on my ohm meter ( set at 20k ohms). I did uninstall the kill switch but did not remove it from where it was ( to avoid having to snake it under the pipes) and tested it. it was good also. I did not remove the coil or flywheel, so i found no need to regap it, would removing the cover mess the distance between coil and flywheel?.......once again thank you for the warm welcome

 

[Scrubcadet10]

Coil ohm readings are useless. i really don't know why manufactures post them, a coil either produces spark or it doesn't. (however when they start to fail they sometimes fail when hot)
with the kill wire unplugged from the coil, try and start. , spray some starting fluid or carb cleane in the spark plug hole or into the carb behind the airfilter .if the mower starts with the kill wire unplugged, there is either a issue with the wire (insulation cracked, shorted to ground) or the kill switch/brake assembly. If it doesn't start, even with the starting fluid, most likely no spark.
Also please post the engine model and type numbers, they will be stamped above the spark plug in the metal housing, or on a metal flap above the muffler.

 

[Kiss4aFrog]

Welcome to MLF turtlemower

.