farmall cub problem

[steve alderman]

have this cub I been working on just rebuilt the motor it wants to run but wont did run for about 15 minutes and died I thought it first was the carb but I tried 3 and all the same result I am thinking maybe the distributor maybe the weights are sticking maybe broke springs if any of you guys have had this kind of problem and let me know how you fixed it

 

[Janicholson]

Start with fuel flow from the tank to the carb inlet. If there is a soda straw stream into a clean can for a minute or two. if it slows to a trickle, or drips, the supply side is restricted. If flow is good, the next step is electrical.
The coils (mag or distributor) can go bad and fail, as can points and condenser in either. The distributor coil can get hot and fail from leaving the ignition on for 15 minutes, or just from old age. The point gap for a mag is .013" for a distributor .020". The spark should jump 1/4" and be blue and nasty crisp. Yellow thready is no good. Distributor shafts can have no easily felt side to side play (not axial, not important) Timing is set to TDC (front cylinder is #1)when not running for both. the mag must trip the impulse coupling at TDC, the points must just break on the distributor. I hope this helps, Jim

 

[notjustair]

Well, let's see...

Does it have spark after it dies? It could be the coil getting hot and fizzling out. Did it have a resistor you didn't put back in? A coil is a cheap part - throw a new one at it.

Does it have fuel? That's about long enough to create a vacuum in the tank if your vent isn't working. If you run with the fuel cap off does it still quit?

 

[steve alderman]

I have a little 1 gallon tank on it for now till I get everything fixed it has a distributor with a 6 volt battery I been over the governor everything seems free I put new points and condenser in the distributor and set the to .020 as I said it ran today for about 15 to 20 minutes it started hard had to play with choke a minute or so it ran well for the time and started sputtering and died it wants to start but just sputters and wont get going now

 

[old]

Very simple trouble shooting is needed.
#1 check that you have a good blue/white spark at all the plugs that jump a 1/4 inch gap or more.
#2 Check that you have a good steady flow of gas form the carb drain plug
Also you may want to check compression. The valve may be out of adjustment but with out know what all has been done to it hard to help more

 

[JAsher452x]

you might want to recheck your valve lash if this is a fresh rebuild just my 2 cents

 

[Andy Martin]

Not to be repetitive, but did you check for spark after it died? And is there a chance you put the wires back on wrong since it ran?

 

[Janicholson]

Assuming the tank still has fuel. the spark is suspect. Jim

 

[steve alderman]

I am thinking the coil now of course the starter don't work so it hard to check the old with the hand crank going to borrow one off my A that I know works. guess it is possible for one to run with a weak coil and runs till it gets hot

 

[steve alderman]

also this is a tractor that I never heard run when I got it the carb was missing and probably sat for some time but couldn't have too long had the straight exhaust pipe and motor was not tight as some said could be valve adjustment but I never had them out and they all worked fine when head was off and looked to be seating but thanks for all ideas I will get after it again in a few hrs

 

[muleboss]

From what you said- My guess is fuel.

 

[steve alderman]

don't think so I got the carb from my lo boy on it and that was working fine with it must be something stupid

 

[john *.?-!.* cub owner]

Did you have good oil pressure? A rebuilt cub engine needs the oil pump primed before it will build pressure. If no pressure, remove the oil filter cover and squirt several pumps of oil in the small hole next to the block on the front side. With the plugs out spin engine over till you see oil start coming back out the hole. Using 12 volts makes it quicker. Then put everything back to normal and start engine. Normally a cub takes 8 or 10 seconds to build oil pressure. On startup after rebuild may take as much as 20 seconds.

 

[john *.?-!.* cub owner]

Also make sure the vent in your auxiliary tank is open. Maybe loosen the cap.

 

[steve alderman]

I got it guys it was the stupid new points that spring got bent or something and they kept popping in and out I had an old set took the file to them put them and she fired right up let it run 15 minutes no problems and I turned it off I knew it was something stupid well thanks for all the imput

Steve