Hard starting "C"

Jackal

New User
I am helping an elderly gentleman with his 1949 C that is hard to start. About 6 years ago we put new rings in, honed it and rebuilt the head. It has a Marvin Schebler carb on it. It will fire once and then the white vapor comes out the pipe which I am assuming is raw gas. He put new plugs in (Champion, J8C, ugh) and it fired and ran great the first couple times and then it gets hard to start until he cleans the plugs again. I asked him to get the Autolite 295 but he said they were unavailable. Does it need a hotter plug? he only runs it 20 minutes to a half hour each time. He hasn't been using the choke since he had someone "adjust" the carb. It was hard starting before and after the carb adjust. the metal base of the plug looks stained but not black and the porcelain looks like the coffee/cream color. He can pull start it instantly in 3rd gear with another vehicle but it doesn't want to start on the starter. It has a magneto. Any help would be greatly appreciated.
 
if i read this right the tractor will not start by starter but will start right up by pulling it.if this is the case then the only thing that changes by pulling it is that the motor is going to spin over faster by pulling it then it does by using the starter,,it is magneto fired so it is not loss of voltage to the fireing of the plugs as in a coil type
ignition. my thoughts are is the starter is not up to snuff as far as spining the motor over fast enough.if the starter is tired or the cables are weak due to age and useage,this may be
an area to check out.the c we had on the farm always spun that motor over with a vengence.. as far as the mag i leave that up to the experts like fred,,etc.
 
The starter was just rebuilt as it would kick out on the initial fire. But I do agree that maybe it is not spinning fast enough...thanks
 
With everything in good working order the engine should not have to spin fast at all. Remember the earlier ones were hand crank, and to crank start them, all you would do is pull the crank up through the compression stroke, no spinning at all.
A mag test and repair is a good idea. Do you hear a loud click from the mag at the top of each compression stroke, indicating the impulse coupling is working?
Get rid of the Champion plugs.
 
How old is the gas? I'd put in fresh gas before tearing into the mag to make sure and cut the gas off until it starts to see if it might be flooding just s bit.Also have you checked the air
cleaner for water in the cup.I'd try starting it with out the air cleaner hose on it.
 
When the impulse clicks it releases the pawl the holds the clock spring in the impulse and causes the rotor to spin really fast making the electric power to cause a spark. If it does not click and spin you do not have spark because the rotor is only turning as fast as the starter is turning the engine. That is not fast enough to make spark. If it was there would be no need for the impulse clock spring. The engine running at idle turns the magneto plenty fast enough to make the needed power for a good spark. When pulling the tractor in gear you would be turning the engine as fast or faster than it would be turning at idle which gives you a good spark.
 
one more quick question on the carburetor. On the marvel, the main jet adjustment, does it meter gas, or air. I have only worked on carbs (car and small engines) that meter the fuel but he was told it is an air adjustment...On carbs that i have worked on, turning it in leaned the fuel and turning it out (counter clockwise) would richen it...thanks
 
The air adjustment at the top is for idle only. Above idle you do not adjust air. You adjust fuel added to the air pulled into and thru the engine by the running engine with the adjustment at the bottom.

The idle speed is adjusted with the stop screw on the back of the carburetor. This stop screw adjustment keeps the throttle plate from closing tight that would stop air flow into the engine all together. The slight width of throttle plate opening is your idle speed. The air adjustment will add air to the fuel in the idle circuit to cause the engine to run smooth at your adjusted idle speed.

The most difficult adjustment is the idle speed adjustment because both the stop screw has to be adjusted a tad at a time to each to keep the engine running. After the idle is adjusted to your needs you then adjust the main jet to the fastest wide open speed you can get. You then turn the adjustment back in until you here a slight slowing of the engine speed. At this point you are as good as you could at home or in the field.
 
(quoted from post at 04:26:15 11/16/17) if i read this right the tractor will not start by starter but will start right up by pulling it.if this is the case then the only thing that changes by pulling it is that the motor is going to spin over faster by pulling it then it does by using the starter,,it is magneto fired so it is not loss of voltage to the fireing of the plugs as in a coil type
ignition. my thoughts are is the starter is not up to snuff as far as spining the motor over fast enough.if the starter is tired or the cables are weak due to age and useage,this may be
an area to check out.the c we had on the farm always spun that motor over with a vengence.. as far as the mag i leave that up to the experts like fred,,etc.

Had my WD that was hard to start on a 6 volt. It worked fine on 12 volt for many years. But a couple years ago I was working on it and I found this when going through the wiring system; no wonder it couldn't get full power.

9QfbOdB.jpg
 

I will agree with you.. I bought a B in Ohio off Craig's List 2 years ago for 200.00. The people wanted it GONE.
I made that happen & bought it for my Son In Law. It would start with one good pull on the Crank, but Not off the
starter. He wanted to switch it to 12 volts, I said NO, it suppose to work fine on 6 Volts.. The Ground & Hot connections
didn't look as bad as the one pictured. I Cleaned them up with wire brush & used a dremmel tool. WOW What a difference.
I mostly work on John Deere's & was flying blind on the Little A/C. But it's a fine tractor with a adjustable frt axle
he hauls in his fire wood with.. I had it for about a month fixing, rebuilding what needed done & then created a Snow Plow
fro a old Jeep for the frt. I don't think you could buy it from my Son In Law for 2000.00 now.
 
I had problem with plugs fouling on a newely rebuilt Ferguson a few years ago. I talked to a Champion Rep and he advised me to get plugs with a higher heat range. I did and never had anymore trouble. He clamed plugs were specked out for different fuel when those old engines were made. I won't say anything about ethynol but you get the drift.
 
(quoted from post at 19:57:45 11/15/17) A good hot mag will wake it up. I rebuild them & have one just like new for sale if you are interested.
Ok, no improvements in starting yet other than it will start right up with a brand new set of plugs the first time and then it goes right back to starting hard. (Need hotter plug?) Another thing that was interesting is that if one plug wire was removed it would start.(more voltage for the other 3?) any thoughts or still a mag issue? thanks
 
(quoted from post at 04:28:45 01/13/18) Have you checked to make sure the valves aren't adjusted too tight?

Nothing has changed with the valves. If I remember right they were just torqued to spec and there wasn't really any adjustment to them when we did the rings 5 years ago.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top