Won't start!

[Dusty B]

New (to me) F-cub - runs great after a short tug to get it started! Good spark, fuel supply OK, runs like a charm once it gets going but just won't fire off on its own?? Pull it 10' and it's going! Open to suggestions! Don't want to tear into it if there is an easy solution but sure has me stumped!

[SamsFarm]

I am just speculating, but I suspect a dirty carb.

Sounds like it is strugling to get any fuel with the vacuum from getting turned over with the starter.

But maybe the pull starting is generating more suction to pull the fuel out of the carburator!

[Eugene]

Magneto ignition system? Impulse coupling not working.

Battery powered ignition system? Mechanical advance stuck at full advance.

[Dusty B]

Magneto ignition system? Impulse coupling not working.

Battery powered ignition system? Mechanical advance stuck at full advance.

Advice on how to unstick it?? Tried using starting fluid - no help!!

[Crimson Tim]

How is the power once it does get started?
If it is difficult to start, but runs ok after a pull start, I would wonder about compression. Maybe rings are stuck or valves need adjusting? I’d consider dry & wet compression tests to see where you’re at and maybe letting some seafoam soak in the cylinders for some days.

[raystractors]

How is the power once it does get started?
If it is difficult to start, but runs ok after a pull start, I would wonder about compression. Maybe rings are stuck or valves need adjusting? I’d consider dry & wet compression tests to see where you’re at and maybe letting some seafoam soak in the cylinders for some days.

I second this. A Cub with poor compression sometimes will start with a pull.

[Dusty B]

Seems to have good power, no smoke, once it is running! Hate to pull the hood if I can avoid it!

[Eugene]

I second this. A Cub with poor compression sometimes will start with a pull.

Seems to have good power, no smoke, once it is running! Hate to pull the hood if I can avoid it!

If your compression tester has a flexible hose, you do not need to remove the hood.

[tldec50]

Seems like these cub tractors have their own starting procedures.my 77 needs 1/4 throttle setting to start right up,my 74 needs 1/2 throttle to start right up,but my 48 will not start with throttle setting just couple notches above the lowest setting.I can crank over till battary runs down but if I put throttle in lowest notch it will start within 2 revolutions.Maybe try different throttle settings and maybe it has a setting it likes.

[Glen]

Hi,
You didn't say if this is the red, 1977 Cub in your other post.

If it is, and has the IH ignition switch, other people have said the ignition switch was the cause of similar problems on other Cubs.
Something goes wrong inside the switch, I guess, and the coil doesn't get power when starting, I think was what was said before.
Connect your test voltmeter to the coil 12 volt power wire, at the coil, and turn the key to start, and see if the coil gets power.

TM Tractor has a new switch, then you can use the same plug to connect it, I think.
You can look at the pic at the listing.

[Eugene]

Timing light. You can check the timing even if the tractor will not start.

You need to diagnose the problem before you attempt any fixes or purchase parts.

[outdoors4evr]

Speculation is all we can do. Here's my guess.
While using the starter, the battery voltage is being dragged down low enough that the coil is not operating. Need to check for spark while using the starter. Make sure that the connections to the battery cables (both ends) are clean and shiny
Does it start fine with the hand crank?

[Dusty B]

Found one major problem, hope its the only one! pulled the carb, one of the PO's had inserted a screen into the intake but when the gad line was inserted, it compressed the screen into a bb sized ball!!! Don't know why it was able to even get enough gas by pulling it to run but it did! Will go out now with a cold start and see if things function the way they should!!

[Waif]

:D Found one major problem, hope its the only one! pulled the carb, one of the PO's had inserted a screen into the intake but when the gad line was inserted, it compressed the screen into a bb sized ball!!! Don't know why it was able to even get enough gas by pulling it to run but it did! Will go out now with a cold start and see if things function the way they should!!

[k hutchins]

So, how did it go after finding the constricted fuel flow?
Also you never posted whether you're dealing with a mag or distributor. Or whether it would start with a hand crank.

That info would help us help you going forward.