ford 9N engine stumble and misses

[frenchie4x4]

Hello all, A friend of mine purchased a Ford 9N with a front mount distributor it also is the 1939-1947 style engine. this tractor also has a loader on it. It is in really good condition. Here is the problem it runs fine until he is going down hill the engine stumbles and misses . he has had the carb rebuilt and has adjusted the float level up and down although nothing helps. He also remembers a similer problem with an old car he had where the coil had a leak in it and the fluid in the coil leaked out creating a problem. If anyone has any ideas we would GREATLY appriciate it. THANK-YOU

Frenchie.

 

[billbill1]

I would check for junk in the fuel tank that might be stopping the flow of fuel to the carb.

 

[Farmwithjunk]

You mentioned "going down hill"? When this happens, is the engine compression braking? I've seen several old tractors/trucks/ect, where there's excessive wear in the timing gears (or chain where aplicable) Under compression braking, there would be considerable change in engine timing, causing backfiring, missing, ect. Same would apply to a degree with a worn distributor. Just a though.

 

[frenchie4x4]

Billbill1 & farmwithjunk, I thank you for your input. I think my friend has flushed out the tank ( it did have a lot of sludge in it). I will check with him on the engine compression braking. We will also check for worn timing parts. Thank you both for your great ideas. If anyone else has any Ideas I gladly welcome them. We may not have time to look at it untill next weekend I will post what we find.
Thank you again. Frenchie

 

[Soundguy]

I especially like FWJ's worn distribuitor theory. Hav ethe guy pop his distrib off ( 2-bolt 5 minute job ).. and see if there is any play int he shaft.. check the advance mechanism as well.

any in/ot or side to side play inthe shaft means he at least needs new bushings.. etc.

Also, remember where the fuel tap is and make sure you actually have enough gas inthe tank to cover the fuel tap when on a grade. Next.. make sure the float is not hanging up on the wall of the carb bowl and flooding the engine out. Over fueld gassers can stumble and sputter from super enriched rich mix..

soundguy

 

[HarryVanderpool]

You say that he has "adjusted the float up and down".
Have him set the float where it is supposed to be.
Get the measurement. Not "by ear"
But first, do points, plugs and timing.
Screw the idle screw in and then two turns out.
Start the engine.
Adjust the Idle SPEED.
Then slowly turn the idle screw in and out to find best idle.
Repeat if nessisary.
If no change, the idle circuit is plugged.
My guess is that the Idle circuit is eather running way lean, or nonfuntional.
Folks often overcome this by running the idle speed up.
Tune up first.
Adjust carb 2nd.

 

[Soundguy]

In case the owner doesn't know, the idle airespeed is the small side pointing jet... IN to enrich, OUT to lean

The big needle in front of the carb that points down is the main needle. OUT to enrich, IN to lean.


Do the adjustments at not much more than 600 rpm.. much higher than that and the idle circuit makes -less- difference.

The advice for a couple turns out on each is a good starting spot.

Set the flaot to 1/4" .. I use the but end of a 1/4" drillbit as my gauge... make sure the flaot moves freely and don't hang on the carb bowl walls. Make sure the float is not 'wet' and that it doesn't have a pinhole in it. To check for this.. microwave a bowl of water till hot.. submerge the flaot int he hot water ( don't burn yourself ).. if there is a pinhole, the hot water will heat up the air inside and you will see a micro-trickle of bubbles escaping from the float.

soundguy

 

[frenchie4x4]

Thanks guys, I really appriciate the input. Hopefully we will try your ideas out this weekend, although it is supposed to rain the next few days.I will definitely let you know how it works out. Again Thank-you all very much.
Frenchie

 

[Soundguy]

Don't worry.. just keep the distrib dry and these old girls hapilly work in the rain!

soundguy

 

[frenchie4x4]

Hey guys, found some time after work today to look at the 9n . The distributer rotor was hitting the cap, BADLEY. My buddy (Shawn) took the distributor out because it needs new bushings around the shaft. It has a lot of play so on a down hill grade the shaft must tilt front? New/remaned distributors Shawn priced were $165+ anyone know were to get bushings or a rebuild kit at a decent price? Thanks again. It's been a long week I'm hitting the sack later. Frenchie.