Allis B starting issue

I have a 42 Allis B that when cold starts on the second or third pull of the crank. When hot however it may not start for 20 turns and at that point I give up and pull it. When we do pull it, it pops right off in a couple feet but all the hand cranking just doesn't do it. Coil has been replaced in the mag as have the points rotor and so on. I have pretty much done everything I can think of to correct this. However all the work I have done still requires that small pull to get it to fire up. Once the temp comes down to a much lower temp this will start like this every time. I just can't understand what the issue is.

I have a WD that done that. The carburetor was the problem, had it bead blasted that stopped the problem.

As Fred2 stated a carburetor can be a problem. Also weak magneto magnets can cause hard starts.

Well used the tractor yesterday and it started much harder. No hand cranking would do it. I did manage to pull it to start but it missed when it started but cleared up. I left it running while I filled the spreader (New Idea 14 A if your wondering) and it seemed to then run fine. Made two loads out to the field. Then the third load the tractor acted up again and spit a sputtered awful again. Like I wasn't getting fuel or maybe spark and then died. No pulling it would do it. I went and did some other things and an hr later came back to it. Temp was done and tractor would pull start but still was missing. I managed to get the thing back to the barn and away but it would nearly stall out when I put it into gear (first only). I have had the mag coil replaced with new and know it had spark good. Still thinking the carb guys? I've had that apart as well and cleaned but I could check it out again. The fuel is crystal clear in the bowl and get a good stream out of the tank. I'm scratching my head on this. I have a three day and can dig into this more this weekend. Just at a loss on this issue still.

If you have access to a timing light for the purpose of visually seeing if you have spark when you are hand cranking would be good. If this was my problem I would suspect the condenser seeing you have a new coil in there. It would be so helpful if you were able to borrow another magneto to observe any difference. My Dad has had lots of "B's" and whenever he's had the problem you describe, almost always without fail swapping mags changed everything.

I would guess with this information you do have a fuel problem. I would start by removing the plug from the bottom of the carburetor and seeing how long you have a good flow before taking anything apart. I have had the neck of the sediment bowl filled with sediment/fine particles of rust. When in a hurry I have blown compressed air back into the tank to clear the passage. If that does not help you might look here.

Just to back up what Dick L was saying. Here is an example of what I had come out of a tank after removing the sediment bowl. This didn't show up in the sediment bowl, because some of the scale was large enough that it wouldn't fit in the neck of the sediment bowl, so it creates a bottle neck and other sediment fills in on top of it. The fuel has to seep through that mess and generates a slow flow. We drained it through a paper towel to save the gas and this is what was left on the towel. It was so surprising I had to snap a photo.

Tank Sediment:


I also looked recently at a sediment bowl that was not letting much gas through though there was no sediment. It had a thick gooey varnish from when the tractor had sat for a long period of time. Even when you start using it again, it doesn't clean that out, it just sits there restricting flow. At first I couldn't tell what it was until I took a dental pick and started scraping the orifice. It came out like brown taffy.

Just a thought, in your case, I might replace the mag condenser after you've exhausted fuel issues. They don't normally fail like your symptoms, more off and on when heat is applied, but it would be something to try if it turns out to be intermittent spark when warm.

Thanks guys I'll have to give the gas issue a try. It may be that fuel just isn't there when she runs. I'll keep you posted.