1981 straight six manual 4x4 project

[Ford F834]

Yes, the aerodynamics are worse than a proverbial barn door as these trucks have recesses, like headlights, that capture the air. That's why Ford flushed them in '87.

Could your fuel problem be icing? Do you have heat plumbed to the air cleaner?

As for timing and tune, have you ever had pinging? If not, you probably don't have enough advance dialed in. I think we've talked about that before, but best MPG is going to be just short of pinging. And that occurs at part-throttle, which means you need to adjust the vacuum advance.

Gary, I do not have heat to the intake, but it can't be ice. I believe the ambient temp was 77*F when I left for work yesterday. This all started after the Furnace Creek gas fill up. I've run enough fuel since then that I don't think the gas is bad, but I wonder if I got some crud in the carb bowl.or maybe a sticky needle valve. I have an inline filter just before the carb inlet but I know they are just gravel catchers. This carb has always had a little stumble when you goose the throttle so I also suspect some accelerator pump badness. It does run really well, so I don't think it has major issues. We will see what a good cleaning and parts kit does. I am not shy about doing that much with it.

I get a lot of pinging with my 240 six, and I've tried various timing settings, but I believe it has a higher CR. With the 300 I have not yet got it to ping but with too much advance it idles like garbage. It gets a very rough stutter and won't idle down to a normal rpm.

Step 1 is get the carb right or replace it. Then I'll break out the vacuum gauge and the timing light and see if I can help it out any. I know they say don't mess with success, but I can always put it back 😉

[Gary Lewis]

Gary, I do not have heat to the intake, but it can't be ice. I believe the ambient temp was 77*F when I left for work yesterday. This all started after the Furnace Creek gas fill up. I've run enough fuel since then that I don't think the gas is bad, but I wonder if I got some crud in the carb bowl.or maybe a sticky needle valve. I have an inline filter just before the carb inlet but I know they are just gravel catchers. This carb has always had a little stumble when you goose the throttle so I also suspect some accelerator pump badness. It does run really well, so I don't think it has major issues. We will see what a good cleaning and parts kit does. I am not shy about doing that much with it.

I get a lot of pinging with my 240 six, and I've tried various timing settings, but I believe it has a higher CR. With the 300 I have not yet got it to ping but with too much advance it idles like garbage. It gets a very rough stutter and won't idle down to a normal rpm.

Step 1 is get the carb right or replace it. Then I'll break out the vacuum gauge and the timing light and see if I can help it out any. I know they say don't mess with success, but I can always put it back 😉

Yes, you can easily have gotten some crud into the carb from the bad gas. Case in point: My original '69 Bee was essentially brand new when I got a tank of bad gas. The gas mileage went away and it ran poorly as it was obviously quite rich. I ran that tank out and refilled - to no avail. I rebuilt the Holley but that didn't fix it.

So I put several cans of gas cleaner in it and we took off from Wichita to Salina. I could see the gas gauge going down, but we made it to Salina on fumes. Filled it up and had the same problem. Stopped at the rest stop on the interstate roughly half way from Salina back to Wichita and pulled the carb down again. It was spotless inside, but there was a gummy residue on the needles. I wiped that off, put it back together, and it purred like a kitten - 'til the lakes pipes roared. (Credit to B. Wilson)

So, I'd tear it down and clean it. And, since you already have a problem with the accelerator pump, and given what Bill says about those pumps going bad, I'd put a kit in it.

As for the timing, you'll need an allen wrench instead of the timing light. Just start dialing in more vacuum advance 'til it pings and back off a turn.

[Ford F834]

Yes, you can easily have gotten some crud into the carb from the bad gas. Case in point: My original '69 Bee was essentially brand new when I got a tank of bad gas. The gas mileage went away and it ran poorly as it was obviously quite rich. I ran that tank out and refilled - to no avail. I rebuilt the Holley but that didn't fix it.

So I put several cans of gas cleaner in it and we took off from Wichita to Salina. I could see the gas gauge going down, but we made it to Salina on fumes. Filled it up and had the same problem. Stopped at the rest stop on the interstate roughly half way from Salina back to Wichita and pulled the carb down again. It was spotless inside, but there was a gummy residue on the needles. I wiped that off, put it back together, and it purred like a kitten - 'til the lakes pipes roared. (Credit to B. Wilson)

So, I'd tear it down and clean it. And, since you already have a problem with the accelerator pump, and given what Bill says about those pumps going bad, I'd put a kit in it.

As for the timing, you'll need an allen wrench instead of the timing light. Just start dialing in more vacuum advance 'til it pings and back off a turn.

Well Gary, you called it on the mpg. This trip was 138.0 miles by the gps, and 8.04 gallons used. Calculates to 17.16mpg. Mountain driving, cold start this morning 22*F in Bellemont. Still not "ideal" mpg conditions but a good yardstick for me, because it is typical for my usage.

[Gary Lewis]

Well Gary, you called it on the mpg. This trip was 138.0 miles by the gps, and 8.04 gallons used. Calculates to 17.16mpg. Mountain driving, cold start this morning 22*F in Bellemont. Still not "ideal" mpg conditions but a good yardstick for me, because it is typical for my usage.

That's very good, Jonathan. But I think with a bit of tuning you can be above 18 MPG, especially when "summer" gas gets there. And that's very good MPG for a truck of this age.

In fact, my 2015 won't do much more than that on the average - although its tow rating is several times what yours is. And it does have a few more creature comforts. And runs like a scalded cat if you step on it. But MPG? Not so much.

[Ford F834]

That's very good, Jonathan. But I think with a bit of tuning you can be above 18 MPG, especially when "summer" gas gets there. And that's very good MPG for a truck of this age.

In fact, my 2015 won't do much more than that on the average - although its tow rating is several times what yours is. And it does have a few more creature comforts. And runs like a scalded cat if you step on it. But MPG? Not so much.

Gary, for a 37 year old 4x4 that I scraped together on the cheap I certainly can't squawk about either mpg or performance. As the cliche goes, "the payments are easy".

[85lebaront2]

Gary, for a 37 year old 4x4 that I scraped together on the cheap I certainly can't squawk about either mpg or performance. As the cliche goes, "the payments are easy".

Not too shabby, I was amazed when I had my 390, it would pull 16-17 highway with a 3.25 gear, LT 235/75R-15 tires and a C6 and it would scat when you stood on it. Didn't do too bad towing either.

[Ford F834]

Gary, for a 37 year old 4x4 that I scraped together on the cheap I certainly can't squawk about either mpg or performance. As the cliche goes, "the payments are easy".

About a week ago I visited the junkyard and picked up a few things for the '81. Namely a new HVAC blower motor to replace my mouse eaten one, an alternator to replace mine that does not seem to charge at idle, and another carburetor (since mine needs attention and I'm down to zero working spares).

I've not been feeling great, and working an odd schedule, so I had not had a chance to try anything. Today before work I decided I had better at least test this stuff while the JY return policy was still in effect. I only had about 35 minutes ...

Went to put the blower motor in and found out that mine has two single prong connectors and the one I pulled (off a 1985) has a double prong connector.. I seem to be stumbling into a lot of this with my 1981. Well, to splice it or return it... that is the question. Not going to happen today at any rate.

Alternator was good. Looks brand new/reman like it just came out of the box and seems to charge at idle. Well, +1 for the day...

Carburetor was a little nasty looking on the outside, but I hooked it up and it purrs like a spoiled kitten. It has the same problem as the other one with hesitating when you stab the throttle. Both have bad accelerator pumps? Maybe, but I am suspicious when two parts behave with an identical fail like that. Both are old JY take-offs, so it's possible, but it does make me wonder about the timing. I think I want to retard it and try again running manifold vacuum. I have no vacuum at idle from the venturi ports, and perhaps it isn't advancing soon enough when you goose the throttle? I will still put a kit in the carb, but it seems like there may be something else here.

Gary, from your carb application info., can you tell me about this base plate number?

[Gary Lewis]

About a week ago I visited the junkyard and picked up a few things for the '81. Namely a new HVAC blower motor to replace my mouse eaten one, an alternator to replace mine that does not seem to charge at idle, and another carburetor (since mine needs attention and I'm down to zero working spares).

I've not been feeling great, and working an odd schedule, so I had not had a chance to try anything. Today before work I decided I had better at least test this stuff while the JY return policy was still in effect. I only had about 35 minutes ...

Went to put the blower motor in and found out that mine has two single prong connectors and the one I pulled (off a 1985) has a double prong connector.. I seem to be stumbling into a lot of this with my 1981. Well, to splice it or return it... that is the question. Not going to happen today at any rate.

Alternator was good. Looks brand new/reman like it just came out of the box and seems to charge at idle. Well, +1 for the day...

Carburetor was a little nasty looking on the outside, but I hooked it up and it purrs like a spoiled kitten. It has the same problem as the other one with hesitating when you stab the throttle. Both have bad accelerator pumps? Maybe, but I am suspicious when two parts behave with an identical fail like that. Both are old JY take-offs, so it's possible, but it does make me wonder about the timing. I think I want to retard it and try again running manifold vacuum. I have no vacuum at idle from the venturi ports, and perhaps it isn't advancing soon enough when you goose the throttle? I will still put a kit in the carb, but it seems like there may be something else here.

Gary, from your carb application info., can you tell me about this base plate number?

Well. you seem to have a knack for finding "the right things" in the salvage, and I think you've done it again on the carb. Carbs Unlimited says that a 7287S YFA is from a 78-84 Ford truck. And Tarheel Blue says his came from an '80 F150 with DS-II. But Mike's Carburetor Parts says it is from a '79.

As for the hesitation when you stab it, perhaps you just don't have enough gas coming from the accelerator pump. If your problem is from idle you might give the idle mix a bit more gas to cover it up. And, make sure you don't have any vacuum leaks.

And on the blower motor, the 1981 EVTM shows 2 connectors and the 1984, '85, and '86 EVTM's shows 1 connector. So I can't tell where the change happened. Sorry.

[Ford F834]

Well. you seem to have a knack for finding "the right things" in the salvage, and I think you've done it again on the carb. Carbs Unlimited says that a 7287S YFA is from a 78-84 Ford truck. And Tarheel Blue says his came from an '80 F150 with DS-II. But Mike's Carburetor Parts says it is from a '79.

As for the hesitation when you stab it, perhaps you just don't have enough gas coming from the accelerator pump. If your problem is from idle you might give the idle mix a bit more gas to cover it up. And, make sure you don't have any vacuum leaks.

And on the blower motor, the 1981 EVTM shows 2 connectors and the 1984, '85, and '86 EVTM's shows 1 connector. So I can't tell where the change happened. Sorry.

Thank you Gary! This carb was on a '82 Econoline I believe. Same vehicle I pulled the alternator from. It has the bowl vent with my other one does not, and the little pivoting fork in the front but is otherwise identical. It has a dashpot and what I think may have been a cold idle solenoid but it's melted. It will all unbolt and leave it looking like my other one.

My plan is to run this one a while to give it a good test and give me a chance to rebuild the other one... then switch and see if I fixed the starving out problem and keep this as a back-up.

Another question for the group... has anyone come up with a more elegant solution for converting to manual choke besides the janky little Help! section kits? After a couple times of tightening down the plastic cups they deform and don't want to adjust or clamp securely, and the cable throw is super short compared to carbs that came with manual chokes. Not a huge deal but the whole set up is just annoying.

[Gary Lewis]

Thank you Gary! This carb was on a '82 Econoline I believe. Same vehicle I pulled the alternator from. It has the bowl vent with my other one does not, and the little pivoting fork in the front but is otherwise identical. It has a dashpot and what I think may have been a cold idle solenoid but it's melted. It will all unbolt and leave it looking like my other one.

My plan is to run this one a while to give it a good test and give me a chance to rebuild the other one... then switch and see if I fixed the starving out problem and keep this as a back-up.

Another question for the group... has anyone come up with a more elegant solution for converting to manual choke besides the janky little Help! section kits? After a couple times of tightening down the plastic cups they deform and don't want to adjust or clamp securely, and the cable throw is super short compared to carbs that came with manual chokes. Not a huge deal but the whole set up is just annoying.

Jonathan - I have an Edelbrock manual choke cable, which is very nice, but I can't find anything beyond that for manual choke conversions on their site. And everything I find on-line looks like a Dorman or HELP unit. Sorry.

But, I did find a promising hit on a thread on FTE where a guy by the name of 1986F150Six converted his. Looks like he used a Dorman unit, but you might ask him if that's true.