1948 cub is hard to start

[Stevetractor]

Does it fire right up with pull starting? My grandfather’s 50 with magneto acted the same. Several tune ups, coils etc over the years, same issue. Finally found a shop that had mag testing equipment, and the bar that runs through the coil was weak. Believe it’s magnetic. The fellow made a new one, and all those years of heartache disappeared instantly. Hope this helps.

[Richard in Ga]

Yes when the rpms get high enough it will start but it doesn't have a magneto

[Rick Spivey]

I have never hand cranked a cub with distributor; the magnetos have the impulse coupling which serves to retard the timing, but also allows the mag to spin faster right at the moment of spark creation. The distributor would already be retarded (meaning not at full advance), and probably doesn't need the extra "oomph" being battery powered. I will say on all my cubs (I hand crank all three) it is important understand how much choke, and when. Being in the south, I usually only need one pull with any choke, just to get some fresh gas into the carb throat. Then no choke, and they usually start within three pulls.

[Eugene]

Yes when the rpms get high enough it will start but it doesn't have a magneto

Your ignition timing is off. It's retarded. Check you ignition point gap, re-static time, and then check with a timing light.

[Richard in Ga]

Checking the timing is gon the list for tomorrow I'll get back after that
Thanks

[Richard in Ga]

Where should the timing be
Advanced?
Retarded?
Or TDC

[Clemsonfor]

Where should the timing be
Advanced?
Retarded?
Or TDC

I would download the manual from the PDF section and read over it well. I don't know the answer to this question either, bit I would be reading there I am thinking that these are fireing at TDC. There is no advance in them I don't believe. If anything it would need to be advanced. It would be hard to do anything if it was retarded.

[Richard in Ga]

Where is the pdf i can download

[Eugene]

Quick Links, upper left of this page for down loadable manuals.

How To Forum for instructions on ignition/electrical system. Read up on how the ignition system works.

You want to become familiar with the information available on this site.

Cubs with distributor have an advance function. To answer the question. You want the engine to fire at TDC during cranking. Once the engine starts and gains RPMs the firing of the spark is advanced so that the spark arrives at TDC.

[Glen]

Below is info for timing a Cub engine using a timing light, which IH recommended be used for a Battery Ignition unit.

Below is a page from the Cub service manual, showing the timing marks.
It should be set so mark number 1 is aligned with the pointer, when the engine is running at slow idle speed, about 500 RPM.
Cubs before about 1955 have 1 timing mark on the pulley, it is mark number 1 in the pic.
Use only the pic and the description under it, they are talking about other things on the page.

http://www.farmallcub.info/manuals/gss- ... 001-43.jpg

If the timing is not right, the distributor has to be turned some to change it.
Loosen the 2 bolts with 1/2" heads that hold the round part of the distributor to the base, one bolt is behind the unit, on the engine side, it is sort of hard to get to.
Use a 1/2" open end, or box end wrench, and put it in from the bottom or top, whichever way it will go in. You can only turn the bolt a small part of a turn at a time.
Don't leave the distributor loose while the engine is running.
Tighten the bolts securely when the timing is set right.

The ignition points need to be good, they get old and burned from use. The point gap needs to be set right also.
If you change the ignition point gap, or put in new points, it can change the timing.
Check the timing after working on the points.
It's part of doing a good tune up.

If you don't know how to use a timing light, I have info for it.

[andersonbw]

Richard, I had similar symptoms on my cub. Very hard to start, but once started, it would run fine. I finally traced the problem to the rotor. Here's a link that shows my troubleshooting:

http://farmallcub.com/phpBB2/viewtopic.php?f=1&t=108258

[Richard in Ga]

Thanks for the help.
Finally got back to the timing issue and that fixed the problem