9n Ford won't start

[Joe TAYLOR]

I have a 1939 9n that I have replaced the plugs,points,condenser,plug wires,rotor,coil and carburator.I was doing some gradeing with it and it was running fine.It surged one time like it was running out of gas then back fired loudly.I put more gas in it and it fired right up and ran a for about ten minutes and died again and I have not been able to get it to start again.I am getting gas through the carburator and a good spark from the plugs but it still will not. Is there any way that it could have jumped time.Any suggestions would be greatly appreciated.

 

[Paul in Edmonton]

I'm sure others will chime in with better technical stuff, but my suggestion is this:

Pull the plugs and hit the spark end of each with a hot propane torch to clean off deposits. These Ford flat heads can't tolerate being flooded at all. If you've been cranking (without starting) with gas getting through, I guarantee the plugs are fouled now, whatever the problem was before. Heck, one time I simply stalled the tractor under too much load, and had to clean the plugs before it would restart. (And I didn't do anything else--that's all it took to allow a restart.)

-Paul

 

[HCooke]

Cannot jump time unless camshaft gear came loose from cam shaft. I would replace the plugs.

 

[Bruce (VA)]

Did you set the timing while the distributor was off to replace the points?

First, replace the plugs. If you flooded it, they're fouled & it will be it next to impossible to start. You don't need to toss them; heat the tips for a few seconds w/ a propane torch to burn off the invisible spark-robbing deposits from today's additive filled gasoline........or wash them in lacquer thinner.

Next, make sure you have a good spark & fuel. There are ways to check for spark & fuel that work & ways that don't. For example, having gas to the carb is nice, but having it past the float is what counts! That’s why removing the bolt in the bottom of the carb is the way to do it. And, same thing w/ spark at the plugs. Some folks think that checking for spark means pulling a plug wire off & looking for one. Well, it's the distance the spark jumps at the plug that gives you the info you want. It takes about 17kv to jump a 3/16" gap & 22kv to jump ¼” in the open air, so that's why you need to use a spark plug. Or, a store bought plug checker. Remember, it’s 14psi outside of the engine & about 90psi at a 6:1 compression ratio in the cylinders & compressed air creates electrical resistance, so you really need the 17-22kv to fire the plugs when the engine is running.

Lastly, while each N has it's own starting sequence, none of them will start well by just yanking out the choke rod & holding it out for 5 or 10 seconds while the engine cranks. This is an updraft carb w/ a gravity fuel system; it is by it's very nature subject to flooding. Too much choke makes it happen.

Try this:

Key on, gas on 2 full turns, clutch in, 3/4 throttle, press the starter button. Let it crank for at least 3 - 4 seconds before you pull the choke rod. Then, don't hold it out for more than 2 or 3 seconds.
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[Joe TAYLOR]

I really want to thank Paul in Edmonton,H.Cooke and Bruce Va. for your help. Each one of you gave me the same advice and I changed the plugs this morning and it started instantly with out even chokeing it.I really appreciate your help.

 

[Bruce (VA)]

You're welcome. Glad to help. And thanks for the follow-up.
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