I have an 81' F250, with a 351m. A 1 1/2 ago or so, the engine was running rough, couldn't get any speed up. To make a long story short, I ( or my local mechanic ) have changed plugs, plug wires, distributor cap, coil, and a few wires. I have had the carb rebuilt, changed fuel filters, and put stuff into the gas tank to get rid of any water. I watched the engine at night, and found a wire arcing, have found a cracked plug, and replaced ground wires, from body to block. It ran much better, but I could still feel it just didn't have the oommff it should. I could still feel a bit of roughness. After not using it for a couple months, I filled it up, was on my way to move some rock for a friend, and It would hardly run. Just to get a couple blocks, I had to feather the throttle, and had absolutely no power. I pulled over and it stalled. Every time I started it, I couldn't rev it up much, and then it would die. Lots of blue smoke from both the exhaust and the carb. I was able to limp home.

I have since checked the fuel supply, and that all fine. But now it won't even fire. Checked the spark at from the coil, at the distributor cap, and saw a weak spark a couple times. I'm wondering if the Duraspark unit could be causing this, and maybe has been malfunctioning for quite a while? I really don't know anything about that unit, whether or not it either works or doesn't, or if it could be partly working. I've been so frustrated at not having a smooth running motor with all its power. (I forgot to mention that I also had the heads done.). I'm tired of spending money on my mechanic, when nothing seemed to work to make it run really smooth when accelerating, and climbing hills with a load.

Anyone out there have any experience with this ongoing problem?

delight

 

After all that you have replaced, you are left with the Duraspark module or the distributor. Do you have a spare module on hand?

 

thanks for your response

I do not have a module kicking around. to be honest, it is one part under the hood that I had no idea what it did. I imagine they are available. Any idea how much they are? As I had said, I had repaced the dis. cap. but not the whole distributor. Could that be causing the symptoms I've described?

Delight

 

Probably around $25-30. I carry a spare for back country trips.