'54 Ford NAA - Losing Power

[Ortis]

Last weekend I was mowing with my '54 Ford NAA. After 30 or 45 minutes, it started running rough and losing power. I barely made it back to the house. Thinking it could be a little dirt in the carb. I drained the carb and cleaned the sediment bowl. I mowed for a while and the same thing happened. Last night I replaced plugs and wires (they looked like the previous owner may have bought them used from Columbus). I started it, and had the same thing again.

Before I pull the carb to give it a spring cleaning, are there any other theories. I see no reason to suspect valves since they have not been touched since '54 probably, so clearances are probably wide, rather than low enough to hold a hot valve open.

FYI, this tractor was not used much last year because of the drought, and so it was not started from perhaps last July until last week. So I could have some gum in the carb.

 

[dgl24087]

You may want to check the coil, distributor cap and points.

 

[ToadHill]

If it's old gas, replace it as well.

 

[Farmwithjunk]

1st place I'd look would be the COIL

 

[Soundguy]

Yep.. I'd check the spark.. that wil be coil or points. if this is 12v converted, and still has the old 6v coil, and no dropping resistor.. the coil or points may be roasted.. if so, get a new coil of the correct voltage.. a napa ic14sb is a 15$ 12v coil.

For points, the following numbers will work

napa cs749, cs753

standard ignition fd 8081
"""" blue streak fd 8081X

condensor

napa fa66

s/i fd75 or fd75x

rotor

napa fa67
s/i fd 108

distrib cap

napa fa352
s/i fd 128

soundguy

 

[Ortis]

Ok. I replace points, condenser, rotor, and spark plugs. That helped a bit. Then I replaced the coil with the NAPA one suggested by Soundguy. The 12v coil with internal resistor does not work on 6v. (That's ok, I probably didn't say 6v loud enough, besides, coils can be fun in various projects). So I found an old coil from my'65 Chevy and put that in. Result: MUCH improved spark, but that tractor still started running rough after a while. Last night, I cleaned the carb. Maybe I'll reassemble it tonight and see what happens.

While I have the carb off, I have a problem that it had when I got it, and still had after my first carb cleaning. Yes, I did install a new needle and seat. Still, I have to turn off the gas if I stop for more than 10 minutes or it keep overflowing the bowl until it is hopelessly flooded. I suppose it could be a float level problem. I found the float level very hard to measure accurately on this thing. Is there a trick, or do I just have to get better at it?

Ortis

 

[Soundguy]

You didn't mention 6v at all. That's why i said '' IF " 12v, then use this coil.. etc.

Also.. the NAPA IC14SB DOES NOT HAVE AN INTERNAL RESISTOR... the primary winding of the coil simply has sufficient turns of the correct gauge wire to equal the correct primary resistance needed for a 12v application.. no power wasting restive element is int he can.. nor is one needed.

Use a 1/4" drillbit stem to accurately set the 1/4" float level. make sure it does not have a hole in it by submerging the flaot into a clear galss of very hot water.. if there is a pin hole, it will make a bubble trail. also make sur ethe flaot is not hanging up on the wall.

if you went to a new flaot needle / seat.. if it is the viton tipped.. they are junk, and have to be seated 1-good time before they will seal 'ok'.. I set the neddle int he seat and then give it a good tap with the blunt end of a chissle to set an imprint of the seat on the tip.

soundguy

 

[Ortis]

I publicly apologize to Soundguy. I read too fast and not carefully enough!

Thanks for the help - especially the float test and the tip on Viton tips. I used needles with those tips for years in cars and neve had a problem. Could be they changed the formula. I'll look for a brass or steel needle next time.

 

[Soundguy]

I've always had better luck with brass needles and seats. Sometimes you can polish up a bras seat with a toothpick chucked into a dremel tool with some toothpast smeared on it.

soundguy

 

[Ortis]

Thanks to everybody for the advice. I seated the Viton tipped float valve needle, cleaned the carb, set the float, and along with the ignition cleanup, it's running great. Now if I could get it to sip fuel the way my Kubota diesel does.......