1953 Ford NAA Jubilee stumbles under load

[Whistlin10Speed]

I recently bought a 1953 ford NAA jubilee, it starts right up and runs great, except when under a load such as bush hogging.

When I bought it I knew it had some carburetor trouble but wasn’t sure to what extent so I changed the oil, checked fluids, filled it up and went out bush hogging. I mowed for about an hour or so with no issues, ran great and had plenty of power. After that first hour, it would surge and stumble randomly and sometimes die.

After it would die it would fire right back up, run good for another few minutes, then same thing, it would stumble and surge and die.

I put a new carburetor on it and adjusted it, still fires right up and runs good, except under a load. I took it out to try and bush hog and it immediately would stumble and surge.

I know it’s getting fuel, which is very clean.

I know it’s got spark, although the plug wires have seen better days and the main wire is basically just sitting on the coil instead of snapping down tight due to the boot being rotted.

Might be worth noting the coil was very hot the first time it died out, maybe bad coil?

Any ideas or guidance?

 

[old]

I recently bought a 1953 ford NAA jubilee, it starts right up and runs great, except when under a load such as bush hogging.

When I bought it I knew it had some carburetor trouble but wasn’t sure to what extent so I changed the oil, checked fluids, filled it up and went out bush hogging. I mowed for about an hour or so with no issues, ran great and had plenty of power. After that first hour, it would surge and stumble randomly and sometimes die.

After it would die it would fire right back up, run good for another few minutes, then same thing, it would stumble and surge and die.

I put a new carburetor on it and adjusted it, still fires right up and runs good, except under a load. I took it out to try and bush hog and it immediately would stumble and surge.

I know it’s getting fuel, which is very clean.

I know it’s got spark, although the plug wires have seen better days and the main wire is basically just sitting on the coil instead of snapping down tight due to the boot being rotted.

Might be worth noting the coil was very hot the first time it died out, maybe bad coil?

Any ideas or guidance?

One should always trouble shoot then parts NEVER parts then trouble shoot. A coil going bad can cause it to run a hour or so then start to have problems. Any time you have a problem you should check that you have a good blue/white spark that jumps a 1/4 inch gap or more. Then check gas flow from the carb drain plug and the flow needs to fill a pint jar in less then 2 minutes. If the carb you put on is an aftermarket carb you could have added to your problem not fixed it

 

[Whistlin10Speed]

One should always trouble shoot then parts NEVER parts then trouble shoot. A coil going bad can cause it to run a hour or so then start to have problems. Any time you have a problem you should check that you have a good blue/white spark that jumps a 1/4 inch gap or more. Then check gas flow from the carb drain plug and the flow needs to fill a pint jar in less then 2 minutes. If the carb you put on is an aftermarket carb you could have added to your problem not fixed it

The fuel flow is excellent, I still have the old carb and may rebuild it but the guy I bought it from gave me the new one, which is an aftermarket Amazon cheapo. It needs plugs and wires anyway as it is just time for a tune up so I’m gonna do that anyway. I will see if the coil/plugs/wires helps. Thanks!

 

[old]

The fuel flow is excellent, I still have the old carb and may rebuild it but the guy I bought it from gave me the new one, which is an aftermarket Amazon cheapo. It needs plugs and wires anyway as it is just time for a tune up so I’m gonna do that anyway. I will see if the coil/plugs/wires helps. Thanks!

If your going to buy new spark plugs get a set of NGK3112 plugs. They hold up better then any plug I have ever used and I use them in a number of my tractors and have not had plug problems since doing so. As for the coil check spark when it dies and if it is weak and the coil is so hot that if you spit on it the spit steams away good chance the coil is bad