MC spark plugs

[John50mc]

I have been fouling my forward sparkplug (Champions) latley so I tried using a pair I had for my 9N tractor ( Autolight 437 ) The engine runs a little better but also hotter. Any spark plug recommendations? My motor is fairly tired but does not smoke much.

[Jimmy in NC]

John-

I dunno about other plugs. I'm running H10C's in the 420 but it usually gets a good work out (gets pretty warm) and it also has a more advanced cooling system if I'm not mistaken.

You may try posting on johnnypopper.com on the message board. There are several people with much more experience with the Debuque tractors. I know the subject of plugs comes up on there very often. I do know that the lil dubuques do better when they get warm and some of them are hard to get to warm up.

Jimmy

[Jimmy in NC]

Here is a quick search I did on the other message board.

http://www.johnnypopper.com/forums/inde ... e5dcad1af8 Looks like the Autolite 216's are wha ... er. Jimmy

[Lavoy]

I have personally had ZERO luck with Champion plugs in John Deeres. I know people will say there is not difference, but a friend of mine that pulls did a test on a dyno because his tractor was dying out at high loads. He ran it on the dyno to duplicate the load, and it died. He removed the new Champion plugs and installed new Deere plugs ( I think Autolite makes them for Deere) and the problem was solved. He made no other adjustments or changes, just the plugs. He also tried some other new Champions with the bad results.
I have had several plug related failures, and not in oil burning engines either. I now use the new plugs from Deere, Autolite platinum, or AC. Have had not troubles to date with them.
Lavoy

[Stan Disbrow]

Hi,

The Autolites have a difference in the way they work the ground, so the spark is a bit more open to the combustion chamber. In the older all-fuel engines, meaning the M and the 40, which have lower compression, it appears that the Autolites produce a faster flame propagation than the Champions. That, in turn, leads to higher combustion chamber temperatures and cleaner burining.

In the later, gas-only, meaning the 420/30/40, which have higher compression pistons, it doesn't appear to matter unless the engine is fairly worn and has lost some of that extra compression (you know, that which prompted Deere to add the '20' onto the '40' to make the '420' and which required, in turn, a water pump to be added).

My 420c, which was dad's and we've had since the mid 1960's, has had Champion plugs in it all along (meaning that it still does) and they've always been fine.

My 430W - yes, I know, talking about a wheel tractor on a crawler board! - which has a pretty worn engine, does *not* like the Champion plugs, but does fine on the Autolites.

Now my 'M' (there he goes again with another wheel tractor) does well on Champion plugs. However, this particular 'M' has seriously high compression pistons in it which are even higher than the 420 has.

There's a *long* story behind the poor little 'M', but I'll make it short and just say that dad, who was a machinist as well as a top racer, remachined the pistons from the M into what they are. I have to run 93 octane or better in the poor thing or it's decidely unhappy. Plus, I can't put much load on it for long, or it'll overheat since it has no water pump. Anyway, with the higher compression it's happy with Champion plugs.

So, I think that's really what it all boils down to: compression and flame propagation (fire moves faster as the pressure goes up). Not that it matters. I'm not brand-tied to much of anything (except Deere when it comes to tractors) and will use whatever works best. In this case, it's pretty easy to get Autolite plugs, which, BTW, were what came in the things from the factory as I recall.

Stan

[Lavoy]

Stan,
Sounds like you need a little water injection on the M to keep it cool.
One other thing that helps an M cool better, is to put a fan shroud off of a 40 on it. Another is to buy the replacement fan from Deere which has a 6 blade fan. I put one on a 420, and no comparison as far as air movement.
Lavoy

[DiggerLarry]

I have had good luck with Autolite 216s. Champions have always been troublesome for me.