Frick Fracking Briggs and Stratton 6.25 HP 190cc Mower Engine No Start When Hot

[WA1GFZ]

All you need is a spare spark plug

[KB2WIG]

or a screw driver passed through the plug clip.


klc

[The Slab Bacon]

or your fingers   

[WA1GFZ]

or some poor fool who happens by.

Hold this wire while I pull the rope
I do the hard job

[AJ1G]

I think I saw reference to the spark checker indicator on the Briggs & Stratton web site.  Using one on a single cylinder engine with a pull start looks like a good idea. You just put it in series with your plug, pull the rope and watch (or have someone watch while you pull).  No need to JS attaching a loose plug to the plug lead and holding the plug threads in contact with the engine block while yanking the starter cord, and safer for your ticker.

http://www.jcwhitney.com/in-line-spark-tester-and-indicator/p2004216.jcwx

[AJ1G]

Looks like its ignition, most likely the coil having some sort of heat related breakdown.  Disconnected the wire from the coil to the kill switch, and am manually grounding it to shut the engine down.  At first, I thought I had nailed the problem with the kill switch, as I got through a few stop-restart cycles without incident.  After a while though, ended up needing more and more pulls to get going again.  Last try was taking the metal shroud around the plug end of the ignition lead off, which was by design, grounded to the body of the plug when installed.  I had read of a case where the plug lead boot had a leakage path to ground through the shroud.  Got an immediate restart after removing the shroud, but may also be the result of the coil cooling off a bit.  Going to put a new magneto coil on as soon as I can get one.  Carb is definitely not flooding the cylinder/plug, and choke is not stuck shut.

[KA2DZT]

Chris,

Seems you're making progress on zeroing in on the exact problem.

Your mower must have a lot more of the unnecessary safety features than mine, which is much older.

I'm still running the original spark plug and coil. My problem was the cut-off switch.  Your problem seems to be spark related. 

You'll find it.

Good luck and let us know what you find.

Fred

[W1RKW]

most of my experiences with engine problems, especially older motorcycles is to target ignition equipment first. 9 times out of 10 it's electrical in nature.  Granted with the crappy fuel we have these days it doesn't take much to crap up a fuel system but I always work ignition first before working to fuel system.

[K1JJ]

Chris,

Some years ago I had a similar problem with the lawn tractor.  It would run until warmed up and then die until it cooled down again. By trial and error I found by mounting the coil away from the engine it would run much longer before thermal shutdown.

I brought the coil into the dealership and the guy said it was "bad" and would cost me $90 for a new one. I didn't trust his "bad" opinion since it ran well until hot and he ran the test cold.

Anyway, I covered it with insulation and ran it like that for another year or two until it finally got worse. Later, they did a tune up and replaced it and the problem was gone.

So, as much as we like to think most coils are indestructable, especially thermal-proof, they do go bad from time to time.

T

 

[AJ1G]

It was the magneto coil.  Starts  first pull EVERY time hot or cold now.  Ordered a replacement through a local hardware store that doe B&S parts and service.  Was about 35 bucks.  The magneto is the complete ignition system except for the magnets imbedded in the flywheel and of course the plug.  No points. Tom 90 bucks for a coil sounds pretty steep..what type of mower was that for?

[KF5FWU]

Glad  ya got it goin. 

[The Slab Bacon]

These guys have just about anything small engine or outdoor power equipment. I've bought a lot of stuff from them in the past. Their website takes a little getting used to to navigate, but they either have / or can get it. they are a distributor for just about everything engine related.

They also offer OEM replacements and the cheaper chineeze knock offs as well, but they give you a choice.

www.jackssmallengines.com