Darn Coil again (I think)

[hrdman2luv]

Yesterday, I was mowing when I ran out of gas. So I refilled the tank and tried starting it. (Briggs opposed twin 19.5hp) It wouldn't start. So I got the starter fluid out, and that didn't work. So, I pulled the plug, placed it on the edge of the exhaust and noticed it wasn't sparking. So I let it set for an hour or so, and tried it again. If fired right up and did fine until I got to a bumpy part of the yard. I noticed it was trying to quit on me. With every bump, it would stall just a little. Until finally it stopped and wouldn't start again. And like before, no spark.

So, I put on another magneto, and that didn't solve the problem either. I disconnected the kill wire, and still no spark. I've got it on right side up. I've got it gapped just right (new business card).. So, I don't know what the hecks going on.

BTW, I placed the wrench on the magnets, and they seem to be good. My wrench stuck to it as normal...

With the kill switch detached, seems the ONLY thing that it could be would be both magneto's are bad. But considering that they're both new (within a couple of months and only a few hours on the one I removed) I'd say the chances of them being bad are very slim. Is there anything else? Something I'm missing? I've had this problem before, but that was because I'd installed the magneto upside down.

 

[ILENGINE]

Multiple module failures within a short period of time, raises the possibility that you are getting battery voltage to the module, at least intermittently, which could mean a short in the wiring, possible key switch problem that is being caused by vibration and bouncing.

Look at the side of the module where the ground wire attaches, and see if the epoxy is cracked, and you even be able to pick up a burnt wire smell if you put your nose close to it.

 

[hrdman2luv]

Multiple module failures within a short period of time, raises the possibility that you are getting battery voltage to the module, at least intermittently, which could mean a short in the wiring, possible key switch problem that is being caused by vibration and bouncing.

Look at the side of the module where the ground wire attaches, and see if the epoxy is cracked, and you even be able to pick up a burnt wire smell if you put your nose close to it.

Nothing that even looks different that when I first bought the magneto's. No smell of burnt wiring. Tested the continuity of both mags. They were OK. So, if it's grounding out, it has to be from under the fly wheel. Because with the kill wire disconnected, then (minus a short from under the flywheel) the magneto, magnets & flywheel are completely separate from anything having to do with the key switch and other wiring to things like the safety switches... Right?

Or am I missing something.

 

[hrdman2luv]

Any tips of taking the flywheel off? The puller doesn't seem to be strong enough. I'm scared I'm going to strip out the small bolt holes.. It's really that tight. I don't have an impact or air tools. And I don't want to go banging on it. I puts some spray lube around the crankshaft end. Maybe it'll break loose.

 

[motoman]

I think if bat current has reached the coil the transistors are toast. Continuity check may not be enough. I have removed my Intek flyweel twice using the two threaded holes and a 2 jaw craftsman puller. I put some preload into the puller and tapped GENTLY with a soft hammer. It should POW off. The nut is at 100 ft lbs. There was a warning by Senior recently that prying on one edge relieves the pressure on the crank thrust bearings seen when using a hammer. I had no problem. The "class" (tightness) fit of the two screws will lend confidence. Screw them in all the way in.


Edit. I have not read here about using a little heat, so I guess most are successful with cold removal. Heat is risky and I would not attempt it without a heat probe or infra red thermometer. Maybe 175F max and circular motion only around the shaft with puller preload applied.

 

[hrdman2luv]

I think if bat current has reached the coil the transistors are toast. Continuity check may not be enough. I have removed my Intek flyweel twice using the two threaded holes and a 2 jaw craftsman puller. I put some preload into the puller and tapped GENTLY with a soft hammer. It should POW off. The nut is at 100 ft lbs. There was a warning by Senior recently that prying on one edge relieves the pressure on the crank thrust bearings seen when using a hammer. I had no problem. The "class" (tightness) fit of the two screws will lend confidence. Screw them in all the way in.


Edit. I have not read here about using a little heat, so I guess most are successful with cold removal. Heat is risky and I would not attempt it without a heat probe or infra red thermometer. Maybe 175F max and circular motion only around the shaft with puller preload applied.

I bought a puller today. It didn't allow the two bolts to screw down far enough, so when I started cranking on the big bolt in the middle, the threads on one of the small bolts pulled out..... The only way to get the bolts in there far enough, is to take the center (pointed) cap off the big center bolt. If I did that, i'd be afraid that it would make the big center bolt unstable.

I don't think I'm missing anything. I got the big nut (and washer) off the end of crank (above the flywheel) that is the only that I know of that would hold it on. I guess it's just that darn stuck.

BTW, this forum needs a "thanks" button.

 

[motoman]

I have often modified pullers. If not too late (damaged thread), try this. Put a little blaster or other penetrate oil around the thread and tap gently with a soft (lead, brass, copper) hammer. Let sit 12 hours or over nite. Repeat for several days. The penetrating oil will work on the top of any corrosion and each soft strike breaks into a new layer of corrosion. Ideally , this is done with a little preload on the puller and tightened just a little (one hex flat) each day. If you have the capability drill and re-tap the stripped hole to next size up. Use an alignment jig to drill and tap so the new bolt will seat fully. A trick that sometimes works on the puller end. Cut and grind it to the desired length. At the grinder point the end by rotating the screw at a slight angle. Then use the big hex nut and maybe another drop in bushing to locate the puller tip. The nut is not screwed down . Leave an air gap for the flywheel to jump into.

 

[mechanic mark]

I bought a puller today. It didn't allow the two bolts to screw down far enough, so when I started cranking on the big bolt in the middle, the threads on one of the small bolts pulled out..... The only way to get the bolts in there far enough, is to take the center (pointed) cap off the big center bolt. If I did that, i'd be afraid that it would make the big center bolt unstable.

I don't think I'm missing anything. I got the big nut (and washer) off the end of crank (above the flywheel) that is the only that I know of that would hold it on. I guess it's just that darn stuck.

BTW, this forum needs a "thanks" button.

https://www.youtube.com/watch?v=KkaD3h8J6es

https://www.google.com/search?q=how....19539j0j8&sourceid=chrome&es_sm=122&ie=UTF-8 take a look at each of these videos & see if they help or not.

 

[hrdman2luv]

I should make a video of this, to show you exactly what I'm talking about... But I'll try explaining it first.

A standard test light (the one with the alligator clip on one end, and the sharp point at the other)... When I connect the clip to the negative post and the pointed end to the disconnected spark plug end (with the plug still screwed into the head) the engine cranks and runs (on the other cylinder that still has a plug wire connected)... When I pull the test light off of the plug wire, the engine shuts off.

I tested the ohms on the kill wire from the plug to the harness, and it's OK. The other end goes up into the key switch.

Also, when trying to crank the engine, with the test light connected to the negative side of the battery, and then touching the magneto, it fires off once. Once it fires off, it continues to turn over, but no spark to the plug.

While turning the engine over, and a test light stuck into the kill wire, the light doesn't come on.

It's almost like the plugs aren't grounded.

 

[mechanic mark]

FAQ | Lawn Mower Safety Tips | Briggs & Stratton Read through this and see if it helps, let us know how it goes.

You can also email Thomas Eidson CRC Tech with B&S with your engine problem: eidson.thomas@basco.com
If you decide to email, send engine numbers: model xxxxxx, type xxxx, trim xx.