15 horse Briggs eating spark plugs?

[Rowdy]

I am pretty green with ohv engines so I thought it would best I asked you folks your opinion. My engine keeps killing spark plugs. They are not carbon fouled or oil fouled as far as I can see. They just stop working. I am at a loss as to why it?s happening. If I pull the plug wire and wedge it 1/8 inch off the top of the plug, it starts up and runs fine. If I connect it to the plug then it won?t run.

It has:

New plugs
New coil
New ignition
New carburetor
Fresh gas
Charged batter

Has anyone ever experienced this? What could it be???

[Facemelter]

I would check the high tension wires for continuity/bad connections/messed up heads where they connect to the spark plugs themselves. Sounds like when you wedge them around you force them to make a connection but when they are resting where they should be the connection is lost

[Rowdy]

Thank you, I will check that.
It was doing it before I converted it over to electronic ignition. And seems like it?s still the same problem but I swapped the coil and plug at the same time so I can?t confirm that the original plug had gone bad. I think already threw it away so I can?t put it back in. When it stops running and I replace the spark plug, it starts and runs like it should.

[ARGOJIM]

What engine model do you have?

[Rowdy]

Jim:
It?s a single cylinder 15 or 16 horse Briggs. It?s the old style with an up draft carburetor. Other than that, I?m not sure of a model number. It was painted before I got it.

[dirtdobber]

So what is the time interval between fails? Does it run only a few minutes before failure or days? Hypothetically if your engine mounts were bad and torque is causing your engine to move around a bit, is there anything the plug can come into contact with and perhaps break the insulation?

[ARGOJIM]

At first I was going to suggest the diode wire, but seeing as it is a single, and you are breaking the ground when you disconnect the plug wire.
I am going to guess it could be either your magneto kill wire shorting either in line or inside shroud, or key switch either bad or searching for ground.
Being as the problem was the same before and after new coil it probably is not that.

I might try disconnecting the kill wire at the coil and go for a ride, if it doesn't shut down that's it. You will have to starve the engine of air to shut it down.

[Rowdy]

Dirtdobber:
I?m on the 3rd plug. The first one was the original that came on the engine. I got maybe 6 hours out of it before it stopped working. I bought the exact replacement and it ran for about 2 hours before it essentially burned out. I?m wondering if it?s the wrong plug but the right dimensions? Maybe the electrode in the center is melting internally? Can a plug be disassembled without destroying it, to see if anything is wrong with it? I?ve never tried to take one apart without the use of a hammer ha ha.
The engine mounts are solid and it doesn?t move for the plug to make contact with anything.

Jim:
I will try that, thank you!

[john swenson]

i read where one small engine mechanic said burning up plugs is usually caused by '' pre-ignition '' . not sure how that's fixed ..but it may be something to check . jboy va.

[ARGOJIM]

I'm curious, does this engine have a low oil shutdown system on it? If so, check level, bypass it and see if it still happens.
Also, have you tried putting any of the old plugs in? Champions used to have a bad reputation of doing this years ago and some were bad out of the box.

[john swenson]

and make sure it is the right plug ... i've had auto parts cross reference plugs of different brands and they ended up being wrong . jb

[Rowdy]

I picked up 2 new spark plugs. Napa had NGK?s so I bought them. I figured that maybe the Chinese plugs will play right with the Chinese electronic ignition lol.

[Rowdy]

Well it seems to be running fine with the new plug. I let it idle for several hours today and it didn?t die. The carb is definitely out of adjustment. It revs very sluggish and blew a cloud of black smoke lol.

[Rowdy]

While I let this turd idle for a couple hours yesterday, I wasted time working on the tire guides. I got half of the guides for one track modified. After I finish those, I?m gonna build a guide to attach to an angle grinder so I can cut the knobs off the inside of the tracks. I bought one of those chainsaw murder wheels from Harbor Freight to use for that. The rubber knobs stand about 3/4? tall, are about 1? by 1? at the base and they?re every roughly every 2?. Removing them will maximize the retention ability of the tire guides. I need to build a guide that won?t let the murder wheel cut too deep into the track, so won?t it ruin it. I?ll post what I come up with. I?m thinking something similar to the guide on a skill saw.

[john swenson]

sounds good ...maybe the carb out of adjustment is definately affecting the plugs . looking forward to seeing your tracks . keep at it , jboy va.