My 1981 F-150 Custom 4sd 351w started running rough a few weeks ago. Time for that carb rebuild I'd been putting off. She'd been hesitating too much and a previous problem had been solved by cleaning the needles and replacing the fuel filter.

As I am a novice at this; and as I bought Hildisvíni with a goal of learning; and as I have basically just rushed headlong into everything I've done to her so far; I bought the kit plus a secondary diaphragm and started taking things apart.

I also replaced the valve cover gaskets and spark plugs.

A few days later and she's still rough, hesitates like crazy, and no amount of tuning the carb seems to help.

So I take a day to relax. Come back and try again, this time armed with some tech help from Holley. I get her running, drive around the block, all seems...ok. No better, really than when I started.

The next day, Sunday, I drive to church without too much trouble. She is boggy and hesitating. I really have to ease her up to speed. After church I can't keep her running. And finally she won't even start up.

Go home frustrated and embarassed. Come back later and install a new fuel pump and fuel filter. The filter (clear plastic) has a shocking amount of black sludge. So I figure I've got it solved. Pump back on, filter back on.

No good.

That's when I realize the distributor is loose. Like, freely rotating through 60 degrees. (Or so it seems now, I haven't measured it).

So now she sits (having been towed in shame) in my carport, ready to meet a new distro cap (for certain) and hopefully not a full distro. (I'm guessing so long as the gear is not chewed up, it is ok.) So long as I have to set the timing, I will replace a belt that's been whining for too long.

And that doesn't even touch my clutch problem.

Hopefully, pics to follow.

 

I feel your pain!

If the dizzy bolt is still in there, just loose, you are probably just fine on the gear.

I assume this is the 1st time you have changed the fuel filter since you bought her? If you have alot of the gunk in there, I would buy another filter and keep it in the glovebox, or under the seat in case you get a bunch more gunk in the next little while.

I assume from your handle that you might be in Utah?

Cheers!

 

Actually, this is the 3rd time in 3 years I've changed the fuel filter. The last time was a few months ago, so I'm thinking where ever the sludge is coming from is getting worse. (Or maybe this was a better filter?)
Other than the gas tank, and checking for deteriorating lines, anything else I should look for?

Actually, I'm in Tennessee. My handle comes from a writing/publishing project about 15 years ago. I have used it ever since all over the internet.

 

grins, well it was a decent guess! lol I am not going to toss any stones on an odd handle, mine comes from an accidental nickname from high school...which was over 20 years ago.

Nah, it is most likely the tank...the only lines I have seen deteriorate and cause sludge were not fuel line rated...some idjit used vacuum hose for a fuel line...he was lucky he didn't burn it down since it was on top of the engine.

The tanks are not that expensive to replace, rockauto has them starting at $75.99...depending on which setup you have.

I am waiting to see if I am going to replace the tanks on my latest project...the gas in the tanks was pretty bad, pumped it all out and replaced with fresh, but there is some crap in the filter already...I am monitoring it and will swap it if it keeps puking garbage into the filter. I swapped the tanks on my 86 4x4 out, dropped both tanks and installed the 38 gallon extended range metal tank in the rear position. It was an easy enough swap, the hardest part being silver soldering the tube to extend the pickup tube lower into the tank. I have heard there is a plastic 38 gallon tank out there, but I have heard mixed reviews on that one.

Hope she quits her bitchin' and gets back up on the road for you! lol

Cheers!

 

Thanks. She's my daily driver, so I need her back.

And thanks for the input on the tank.

 

You might as well replace the sending unit and the straps too!

 

X2, what he said!

 

Not debating possible fuel tank issues, but how "well" did you clean the carb?
Mine was filthy, and the body even had a coating of old fuel and oil that changed the color of the carb. I soaked everything in a solution from the auto parts store (the gallon can with a parts basket inside)
This removed so much crap and grime from the carb i had to run the solution thru a filter to get the crap out of it.

This is debatable but i have always been a filter before pump guy, so when i re-did my 86 5.8L fuel system mine had a return system i deleted and added a filter before the mechanical fuel pump and eliminated the filter at the carb.

 

I've taken the belt and suspenders approach. I kept the stock config filter at the carb inlet.

At the pump inlet (converted to electric only, deleted the stock mechanical pump) I added a second filter. I used the same filter as at the carb inlet for simplicity.

The filter at the pump inlet is the primary filter now. Unlike the stock config, the pump is now protected.

If the pump starts to disintegrate, the filter at the carb inlet will catch that.

Been running several years like this with no issues.

 

Still no start. Will crank and crank.
It's getting gas.
I have checked and rechecked and triple checked the firing/wiring order.

Some PO bonehead numbered the wires according to their position on the cap instead of the cylinder firing order. Apologies if that's a thing that folks do, but it seems to be a recipe to mistakes.

My Father-in-law told me to check it fire at the plugs by removing a plug, reattaching the wire, grounding it with the treads to the block using jumper cables. Turn the key and look for spark.

It sparks, but seems yellow and weak, not blue and strong.
Definitely getting gas.

The distributor is Duraspark 2 with the single magnetic pickup assembly.

Any suggestions?

 

Continued troubleshooting. Having checked and rechecked the timing (by eyeballing the rotor orientation at the 10 mark) and the wiring. It seemed time to check the compression.

While waiting for the gauge to arrive, I noticed the starter solenoid seemed a bit corroded on the negative side. So I loosened it to clean it and ended up breaking the nut off completely.

*&*#@%

And, the negative terminal on the battery wire came completely loose.

And my father-in-law's compression gauge didn't have a connector big enough for the plug hole.

As Frank Costanza says, "SERENITY NOW"

Next Question: once I get a solenoid and wire terminal, should I be looking at the Ignition Module? Is that something my local parts store can test? Or I can test?

 

If you have spark, then you are probably ok. (ignition module working, coil working, dizzy working.) None of these really put out huge fire unless the battery is pretty new and fresh.

Negative side of the solenoid? They are a chassis ground, both of the big cables are positive. 1 from the battery, the other goes to the starter.

Are you getting enough fuel that there is some in the filter, or is it just a little trickle in the bottom?

Also, for kicks and giggles, you might try running a set of jumper cables from the neg terminal on the battery, to the block...just to make sure you do not have a grounding issue.