While I'm Beggin' For Help (Long)

I've been turning wrenches since I was 6 years old, but I've got an IH gasser that is just drivin' me up a wall.

It is a 301 replacement engine according to the numbers on the block. I completely serviced it and tuned it up to the max when I got it. All new ignition parts, o/hauled the carb and set the valves.

Compression measured 127 pounds across the board and it uses no oil at all. There is a little slop in the distributor shaft.

I put in Autolite plugs.

The thing just runs like a champ as long as I'm "pushin' it" hard. But, if I'm just putzin' around the yard and doing odd jobs for a few days, especially at slower speeds, it starts to sputter and miss.

Always on plugs 1 and 2. The plugs are carbon fouling. Not wet in any manner; they look just like you rubbed 'em with a charcoal brick or something. Like I say, not a hint of wet oil fouling.

I pull the plugs and clean 'em up, put 'em back in and the darn thing runs like a million bucks again. Engine is to specs and the coil is throwing an easy 3/8" spark.

The only IH 6 pop gas engine I've ever been around was the ones in our old trucks. We tuned those things up every 15 to 18 years weather they needed it or not and they always ran great.

I'm really starting to suspect these Autolite plugs. Anyone got any ideas? Could that distributor shaft be dealing me fits?

Thanks,

Allan

You may want to move the plugs around first and see if the fouling moves with it. Or you could have a manifold leak. That would explain the fouling. Believe it or not that will foul a plug. I have a feeling in my gut that’s what it is being its two cylinder side by side. I have seen this before on the old GMC V6’s. They have a venting valve under the valve cover that would get the guts sucked out and if you didn’t know it was there, it would drive you crazy try to find out why those two cylinders was missing at a idle. Try squiring some choke cleaner around the manifold at an idle and see if the engine changes.

John In Iowa

Not sure if low ash oil is the answer if it’s not burning oil.

Are you running an ethanol blended fuel? I have found that if I run ethanol in my M under the loader my plugs survive the idling and light work a little better.

If you don’t find a leak in the intake on the rear cylinders (meaning you would have adjusted the carburetor richer to compensate) then I’d suggest a different brand of spark plugs and or a hotter range. I had a 69 Chevy 327 once that would run a long time on AC plugs, but not very long on Champion or Autolites. I had a 75 Chevy 350 that ran 48,000 miles on a set of Champions. Go figure.

I didn't get a chance to dig to deep but I'm going to recheck the point gap and make sure I didn't mess anything up in there.

I've always had trouble with fouled plugs in both the A and the BN and was hoping the Autolites would help but so far it hasn't worked out too well. That being said I might have to play with the carb a bit, Grandpa always ran them rich, maybe the Autolites balk at that.

Work 'em and they'd run great. Let 'em idle for more than a couple of minutes, and they'd start missing and sputtering, just like yours.

Where did you get the parts to change it over to solid state?

Thanks,

Allan

What about the possibility of an intake manifold leak thats causing one end of the engine to run a little bit leaner than the other. If you set the idle mixture for best idle you would easily have compensated for a small leak. A small leak would also have little or ne effect under load.

Other than that, the only thing I can think of is to try hotter plugs. My late father was mechanic/shop foreman for an IH dealer in Oregon when I was growing up in the 60's. I never paid much attention to why, but I seem to remember using Champion J-8 spark plugs in most of those old engines. I really have no idea if Autolites could or could not be a problem.

Maybe this'll trigger someone else's ideas...

Keith

I don"t know about low-ash oil, I guess. I"ve just been running 30 wt diesel oil in everything.

What gets me is that it runs so darned good until I start putzin" around on it. Maybe that darned advance is messed up.

Thanks Guys,

Allan

personally i do not know if it is the plugs or not, try switching the plugs around and see if it is the same plugs in different cylinders that foul.