Briggs 23 hp Vanguard

[KE4AVB]

Just wait until you run into an fuel injection system on one these small engine but of course you probably done ran into the M-troincs on some Stihl saws and the Autotune on some Husqvarna saws if you work on a lot of chainsaws.

[Bret4207]

I haven't played with any of the newer saws with the electronics. I'm not going to fool with something I know nothing at all about.

I have to pull that engine out to get the shrouding off to see exactly what wiring I have. Took a quick look at the carb and saw no fuel shut off solenoid. Huh, that makes the fact the engine runs after turning the key to the off position support the cross firing coil theory. This got me to thinking, (always a dangerous thing). I seem to recall having to replace some wiring after some was ripped apart by ice a couple years back. I wonder now if I caused the problem I'm having. I suppose this is what happens when you have way too many irons in the fire.

[Bret4207]

I finally limped the skid steer into the garage and pulled the engine. I got the suspected bad wiring harness out. Doing a simple continuity test, the harness appears to be good, eg- I get continuity in one direction, but not the other.

I'm not sure where to head now. I'm going to review the posts here and see if anything jumps out at me. The engine is still backfiring as it runs and seems to have reduced power.


ETA- Reading through the posts here I see something confusing. The tabs on the Briggs coils are for grounding as I understand it. They are the "kill switch", correct? When I just pulled this wiring harness apart the ground/kill wire went to a "junction" with wiring coming off what appears to be a relay. The relay doesn't appear in any parts diagram I can find. An internet check shows it to be a Tyco relay # V23234-A1001-X036. I don't see that anywhere in the parts diagram. I am assuming that is the relay to shut the engine down? I'm not sure how to post a picture on this forum system. The confusion comes from my wondering how or if that can be part of the problem. Can that be bad and maybe be shorting, so to speak, inside giving me the intermittent spark issues? It seems likely to me. And FWIW, I cannot find a diagram showing the same wiring I have on this engine.

[bgsengine]

simple way to diagnose that - disconnect kill wire at harness connection , if problem goes away its a wiring issue, if not, disconnect the kill wires from coils and re-test, if problem is still there, it's not in the wiring (assuming your backfire is actually ignition related)

[Bret4207]

I was thinking about that. Wish I had a way to run the engine without putting back into the machine. At this point I'm inclined to think I screwed up the wiring after the ice took it out somehow. I'm not going to put the engine back in with possibly bad coils or with screwy wiring. It's just no fun working while doing a headstand inside that thing.

[bgsengine]

I don't see why it wouldn't be able to be run outside of the machine, all you need really is jumpers to hook up battery ground to engine block, jumper the other cable to the starter to start it up, and supply another 12v jumper wire to the carburetor solenoid, leaving the ignition ground wire disconnected. If there is a carburetor solenoid working properly, once you remove the 12v power supply from it it'd shut the engine down, or othewise just a jumper wire from the ignition ground wire to touch to engine block to shut down.

[Bret4207]

I'm just now getting back into this engine now that it's warm enough to work. I think the relay I mentioned earlier on is bad. I believe it shuts the fuel solenoid and grounds out the coils, except it doesn't seem to be grounding them out correctly since it doesn't shut down when I turn the switch. The plan is to run a simple toggle switch for the kill wire to the coils, leave the relay hooked up for the fuel shut off and fix the other broken wires I found to the charging system.