51 B Fouls Plugs

ndgregor · Jul 6, 2017

I recently installed my brand new WICO C magneto and spark plug wires and got the tractor up and running. I had posted a question on this forum about how to time the magneto and many of you fine folks helped me to do it properly. When this tractor runs, it seems to run great. There are two problems with it however. It is very hard/temperamental to start. It takes a lot of tinkering with choke and throttle and it seems you have to get it just right to fire but not flood. Often times I just take a plug out shoot some starting fluid in the cylinder and it fires right up. This is not the primary issue I am having, just mentioned it in case it is related to the next issue.
Now the other, more annoying issue to me is the plug fouling. The plugs that were in there were an NGK variety. I can run these for about 20-30 minutes until they foul and the tractor shuts down. This is a dull black coating which to me looks like excess fuel/carbon build up, not an oil burn. The tractor does not smoke at all when running, either black or blue. Current idle needle position is ? of a turn out, and load needle position is 1 turn out. Air cleaner stack is removed from front of carb to make sure airflow is okay.

I had read that many folks on this site recommend Autolite 3116 plugs. I bought a pair and brought them back and the tractor simply would not run with those plugs. I have no idea why. Does anyone have any idea what else I can try and do to prevent the fouling?

notyalc · Jul 6, 2017

(quoted from post at 04:49:48 07/06/17) I recently installed my brand new WICO C magneto and spark plug wires and got the tractor up and running. I had posted a question on this forum about how to time the magneto and many of you fine folks helped me to do it properly. When this tractor runs, it seems to run great. There are two problems with it however. It is very hard/temperamental to start. It takes a lot of tinkering with choke and throttle and it seems you have to get it just right to fire but not flood. Often times I just take a plug out shoot some starting fluid in the cylinder and it fires right up. This is not the primary issue I am having, just mentioned it in case it is related to the next issue.
Now the other, more annoying issue to me is the plug fouling. The plugs that were in there were an NGK variety. I can run these for about 20-30 minutes until they foul and the tractor shuts down. This is a dull black coating which to me looks like excess fuel/carbon build up, not an oil burn. The tractor does not smoke at all when running, either black or blue. Current idle needle position is ? of a turn out, and load needle position is 1 turn out. Air cleaner stack is removed from front of carb to make sure airflow is okay.

I had read that many folks on this site recommend Autolite 3116 plugs. I bought a pair and brought them back and the tractor simply would not run with those plugs. I have no idea why. Does anyone have any idea what else I can try and do to prevent the fouling?

I would suggest that your carburettor needs a good overhaul, and the float level checking.

Only way to clean it is to remove all of the drill plugs, main jet shafts etc.

Then clean out all of the passages.

ndgregor · Jul 6, 2017

Should have mentioned that in the previous post. Carb has
been cleaned, at least to the best of my ability. I bought the
drill bits and cleaned all the passages, including the "secret
one. New gasket kit as well. I will have to check the float level,
I believe I set that but I need to check its right. Thanks for the
advice.

John T · Jul 6, 2017

First of all with that Wico C Magneto I recommend NON Resistor plugs of the highest heat range available and wire core NOT carbon suppressor, plug wires.

Things that can reduce excess fuel fouling are 1) Run the carb as lean as possible 2) Insure the air cleaner and oil batch and pipes etc are all clean and free 3) INSURE THE CHOKE PLATE IS OPENING FULLY 4) Use shutters or other radiator air restrictions to get and keep the temperature up 5) A good hot blue spark and run higher heat range of plugs and keep the ignition well tuned

If you run good hot non resistor plugs and wire core plug wires, keep the carb lean and the temp up but she still fouls ID SUSPECT A CARB PROBLEM

On the starting the start/impulse needs to occur right at TDC and if too late she's harder to start. I like mine as advanced as possible BUT NOT SO FAST IT KICKS THE FLYWHEEL BACK. Mine likes to start with the throttle at idle.

Others may have different opinions but this is what works best in my experience

John T

ndgregor · Jul 6, 2017

What is your recommendation for hot plugs with a WICO C? I read someone mentioning autolite 388?

John T · Jul 6, 2017

The near original heat range for an 18mm resistor plug would be Autolite 386 but 388 is a bit hotter. HOWEVER, as I noted with a Magneto Id prefer a NON Resistor plug which in Autolite is a 3116, but you say they don't work for you???? If you can cross a NON resistor plug in NGK or Bosch or Denso etc that is near the 3116 or hotter heat range Id give that a try. Actually I don't think the brand of plugs is going to solve your carbon sooty fouling problem, but instead running at higher engine temperatures, hotter non resistor plugs and wire core plug wire, with a lean carb and no choke plate or intake air restrictions and timed properly.........

John T

ndgregor · Jul 6, 2017

Okay, thanks. I agree the brand of plugs shouldn't make a difference but it was odd to me it wouldn't run with the 3116. Does the spark plug gap need to be adjusted or out of box okay?

I will try and lean it down further with the needles. Is it normal to be under one turn out on both? The book said it was supposed to be around 1-1 1/4 turns out? I've got wire core plug wires, choke plate IS fully open and there are no air restrictions. Maybe my timing is a bit too delayed? That's worth a check. Could i play with timing while it's running, rotate the mag CCW to advance?

Thank you!

Kent Petersen · Jul 6, 2017

Hook the air cleaner up ,it will help with the carb setting and i would install a Delco dist. A 1951 B came with a Wico XB mag or Delco Dist

PJH · Jul 6, 2017

You've obviously had the carb apart.

When I was working on the carb for my 50, I noticed that the little pot metal lever assembly on the OUTSIDE of the carb had a depression worn inside it and the choke plates were not opening fully. This probably wouldn't make it start hard, but it might contribute to the sooty plugs, depending on how badly it was worn, and what other issues were present. I can't remember if your B has the same type of choke lever, and I'm betting you've already looked down the barrel and would have noticed something amiss.

Here's an example of the choke lever that I'm talking about.

PJH · Jul 6, 2017

You can screw a little hose barb fitting into the bowl drain and slip a piece of clear plastic hose on it. Curl the hose up beside the carb and the gasoline will flow to the level of the float setting, like a sight gauge on a boiler. Quick and easy, and it will save you from having to take the carb apart to check the float level.

Leroy · Jul 6, 2017

Brands can make a difference.I had 49B and 51 A and with the champions even with the uotes avaible they would foul bad. Plowing with the tractors would put in new set in morning, clean at noon and repete next day for 2 weeks in a row. That was when TSC had their own brand. Got a set for each tractor and never touched the plugs for 10 years. And yes we ran the hottest avaible all the time even under the heavies load of plowing and disking.

Leroy · Jul 6, 2017

Brands can make a difference.I had 49B and 51 A and with the champions even with the hotest avaible they would foul bad. Plowing with the tractors would put in new set in morning, clean at noon and repete next day for 2 weeks in a row. That was when TSC had their own brand. Got a set for each tractor and never touched the plugs for 10 years. And yes we ran the hottest avaible all the time even under the heaviest load of plowing and disking.

John T · Jul 6, 2017

I wouldn't trust the out of the box plug gap, go ahead and try a 0.025, NOTE that's just a rough in experimental "guess" subject to actual tractor and engine GO BY THE EXACT SPECS NOT ME. While the book is "often" close on the initial carb rough in settings, each carb is a bit different and it depends on wear etc., so Id still slowlyyyyyyyyy tweak it in leaner a bit at a time and see how she does REGARDLESS OF ANY EXACT BOOK SETTING as wear matters. YOU JUST CANT HAVE THOSE FLAT BLACK SOOTY OVER RICH PLUG DEPOSTS. Indeed, your advance run timing may be a bit slow, she needs to snap/impulse right near TDC, but when running (over 250 RPM when impulse stops functioning) maybe be at 20 to 30 BTDC (rough in guess) depending on make and model and fuel. I shoot for 25 BTDC at full RPM. AGAIN LOOK AT THE SPECS for your tractor and engine etc.

Yes you can adjust timing while running BUT BE AWARE if you rotate the mag in the governor CCW to advance CW to retard, you are changing BOTH the advance run timing as well as the start/impulse timing.

When I and my late friend Duane Larson gave Workshop Seminars we approached mag timing a bit differently. I set the initial start/impulse at TDC and then as long as the run time advance was in the 20 to 30 range (preferred 25) I let it be, while he meticulously set the run time advance (say at exactly 25 BTDC) and then kept re adjusting the lag angle until it impulsed at TDC.

PS Id still once more try the Autolite 3116 plugs

John T

buickanddeere · Jul 6, 2017

(quoted from post at 08:52:01 07/06/17) What is your recommendation for hot plugs with a WICO C? I read someone mentioning autolite 388?

Several Somebodies keep on saying don't use the resistor 386 and 388 plugs or resistor wires for a reason.

RandyB(MI) · Jul 6, 2017

Just an FYI , running the idle needle too lean will cause it to suck off the load nozzle to stay at speed. The fuel coming out of the load nozzle at that slow rpm will not be atomized and will be just dribbling into the air stream and cause a rich/ unburned fuel condition. This is why ,when setting the idle needle you must have it at fast idle and then close load needle completely and then set idle needle for leanest position without killing tractor (1/4 turn back open from when tractor dies. Constant "helping out" of the load nozzle will foul plugs. My '50 B test tractor uses 3116,s and mag and instant start and no problems running.

Chasing_Deere · Jul 6, 2017

Is this model B a gas tractor or is it an all fuel tractor? Which model carb is on it? Dltx 67 or 73 ?

John T · Jul 7, 2017

Good post, while I run my idle needle as lean as I can I AGREE THERE CAN BE A TOO LEAN POSITION.......... When bragging at a tractor show how slow I can idle it down is one thing but after the crowd leaves I open it back up about 1/4 turn lol

John T

ndgregor · Jul 7, 2017

It is a gas tractor with a DLTX 107U carb on it. Apparently this was a universal replacement carb offered later on?

ndgregor · Jul 7, 2017

Randy that is an interesting point. I will try setting the idle needle per your suggestion, with the load needle closed and at high idle. I did not set it that way previously. Any particular way to adjust the load nozzle you recommend? I don't have an easy way of putting a stationary load on the tractor.

Chasing_Deere · Jul 7, 2017

I never heard of that carb but would bet that might be your problem. If that is a straight gas tractor not all fuel it should have a DLTX 67 carb on it JD part #AB3533R There is a difference in the gas carb and the all fuel carb. The all fuel carb has a calibrated economizer plug where as the gas carb has a calibrated economizer orifice. Old guy that lives behind me worked on JDs for the last 60 yrs just fixed one that no one else could and that was the issue they had the wrong carb on it and it would run for almost an hour then shut down and no one could figure it out, he switched out the carbs to the right one and it runs all day no issues. so maybe something to check hope this helps.

51 B Fouls Plugs

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