It had been running fine...

Tue Jul 09, 2013 12:51 am

Last week I took my refurbished 1949 Cub back to my farm in Miss. to try out the Woods mower and show it off to a few cousins. I ran it up and down the road, as well as cutting a good bit of grass. The next day, I pulled it out of the barn and hosed the dust off, being careful not to splash water on the magneto or cables. Every since then, I have not been able to crank or run it reliably. I first ran the battery down and had to wait till the next day while I charged the battery. It turns over OK, but is balky trying to start. I usually can get it started, but if I try to run it in any gear other than reverse or first, it acts as if it has no power and bogs down and quits. I have a pristine gas tank with an original style fuel bown and metal gas line. Removing the gas line from the carb gives what seems to be a satisfactory fuel flow. Removing the plug on the side of the carb bowl gives what also seems to be adequate fuel flow. I have pulled the carb twice and completely disassembled it. There was no water or visible trash. All of the orifices were blown out and seem to be clear. The float seems to work properly and was set to specs when I went through the engine last year. I have not made any changes to the timing/ignition since I overhauled the engine, and it has been running flawlessly till this past week. As a last resort, I took the carb off my unrefurbished 1947 Cub and brought it to Birmingham today. I will clean it up and put in a rebuild kit. If I can't get the 1949 going with it's original carburetor, I will then try the other one. Hopefully that will point me in the direction of the problem. I am convinced that it is a fuel problem, but would like any suggestions from folks more experienced than I. (To my shame and embarrassment, I had to load the Cub on my trailer for the return trip with a come-along.)

Re: It had been running fine...

Tue Jul 09, 2013 1:48 am

Stan, I know you said that you were careful to not hit the mag or cables with water, but have you pulled the cap just to make sure that there was no moisture in there?

Pull the air hose from the carb, give it a shot of carb cleaner and try to crank it again. If it fires off, look again for fuel issues. If it doesn't, look at the wires and mag.

Re: It had been running fine...

Tue Jul 09, 2013 5:03 am

I'm betting on an electrical issue as well; leave the carb alone until you confirm good hot blue spark, at the right time.

Re: It had been running fine...

Tue Jul 09, 2013 6:50 am

I think the guys are right on track with an electrical issue. Pull the caps on the distributor and voltage regulator and check for moisture. spray with WD-40 if necessary.

Re: It had been running fine...

Tue Jul 09, 2013 8:05 am

thiggy wrote:......... I first ran the battery down and had to wait till the next day while I charged the battery. .....
I've done that as well hoping they will start, but in reality if it normally starts easily and all of a sudden doesn't, there's something wrong that continued cranking and wishing won't fix. I sometimes have to make myself turn loose of the starter rod and investigate instead of mumbling "ccoommee oooonnnn"

I'm thinking electrical as well for what it's worth. When you get it sorted out not only will you have impressed the cousins with the tractor but your mechanical ability as well with a casual "yeah, I fixed it myself!" We all won't tell :wink:

Re: It had been running fine...

Tue Jul 09, 2013 8:35 am

Stan:

Agree with the guys comments - electrical issue. Remember - to check all your grounds and the connections making sure all are clean and bright metal. WD-40 is your friend when it comes to moisture in the cap. :)

Re: It had been running fine...

Tue Jul 09, 2013 8:47 am

OK, I'll go with the consensus and start looking at the ignition system. Since it is a magneto ignition, I don't think the regulator/generator can have any relation to my problem (unless it won't charge once I get it running). As I have done nothing to change the timing, I doubt that would be an issue. I'll pop the cap and apply some hot air from my heat gun to ensure it is dry. I kind of hate to spray WD40 on things which will make them oily and collect dust. Is there any kind of spray which would not leave a residue to be cleaned up? Thanks for the suggestions.

Re: It had been running fine...

Tue Jul 09, 2013 5:30 pm

Check the quality of your spark. Looking for crisp and blue/white, not yellow. If yellow, could indicate problem with coil. Also need to check points condition, clean and regap to 0.013". Be cautious when replacing the pinion and rotor, as they line up in a specific location (scribe lines on plastic parts, and pinion has a flat side to match shaft). Insure there is not too much wear between pinion and rotor, it shouldn't wiggle too far in either direction.