'87 f150 351 truck carb advice needed

[ebinmaine 67,695]

My father has a 1987 F-150 extra cab four-wheel drive. 351. Automatic.

 

OFF-ROAD PLOW TRUCK ONLY

 

 

For several years now it has given him great fits when he tries to start it. Instead of fixing it properly he's been using starting fluid and messing about a fair amount sometimes.

 

I don't know the exact time period but when it sits not running or used for a few days there's no longer fuel in the carburetor. It doesn't leak out on the ground and it doesn't seem to be throwing it into the oil pan so I assume it's siphoning back.

 

I think I've been telling him for five or seven years now that he needs to change the carburetor and for whatever reason he's decided maybe......

 

 

What is on there now is assumedly the original Ford carburetor. He's converted it to manual choke so another one of those is fine.

 

 

No emission controls need to be put back.

 

 

He's looking for a carburetor that would be efficient and easy to start.

I told him he should maybe think about an aftermarket Edelbrock replacement.

Absolutely open to other ideas.

 

 

Which one? Why? What do we need to know? What kind of hurdles or stupidity we going to run up against?

[Maxwell-8 4,277]

HOLLEY EFI! hahaha

[JoeM 7,874]

23 minutes ago, ebinmaine said:

Edelbrock replacement

Yeah they match up pretty good. Going from memory. 

Just wonder what is wrong with the FOMCO one? If the throttle shaft is good probably a rebuild??

[WHNJ701 4,165]

87 was the engine swapped out, I thought they were all efi by then?

[squonk 41,164]

86ish is when throttle body injection started coming out. Could be a early 87. Never seen a Ford carb worth a  

 

Better off dribbling fuel into the intake with a bucket. Or an Edelbrock replacement would be a good choice. What kind of shape is the fuel pump in? 

 

Edited February 1, 2021 by squonk

[ebinmaine 67,695]

56 minutes ago, JoeM said:

Yeah they match up pretty good. Going from memory. 

Just wonder what is wrong with the FOMCO one? If the throttle shaft is good probably a rebuild??

That, I don't know.

He has a good old school mechanic that has told him it should be replaced. 

 

 

 

12 minutes ago, squonk said:

fuel pump

I'd had that same thought Mike. Could a bad diaphragm in a mechanical pump empty a carburetor?

 

[squonk 41,164]

Is there a return line on the pump? It could siphon back to the tank.

[ebinmaine 67,695]

27 minutes ago, squonk said:

Is there a return line on the pump? It could siphon back to the tank.

I'll have to find out from him after the storm...

It's an emissions  vehicle so it makes sense that there would be a return line

[lynnmor 7,315]

If it has the Holley carb, either one of the two parts with diaphragms is knackered,  Just get a kit and rebuild it.'

 

See photo on this site.

[Maxwell-8 4,277]

Do they have return valves?

 

Maybe a bad gastank vent? Building up some vacuum in the gastank

[Darb1964 1,044]

Some of the o!d ford trucks had a off brand carb. A guy I worked with years ago had one, it was a nightmare, nobody could get right and he was told it could only be replaced with the same brand, I can't remember the name brand. Not sure, I know he ended up getting rid of it.

[WVHillbilly520H 10,373]

1 hour ago, ebinmaine said:

I'll have to find out from him after the storm...

It's an emissions  vehicle so it makes sense that there would be a return line

According to RockAuto, 86 and 87 same carb basically Holley style model 4180, each to their own, but you couldn't give me 2 Edelbrocks over a Holley style carb for ease of maintenance and tunability, yes they are easier to work on than a Q-Jet but nonetheless I would stick with the Holley style, those older castings and gasket materials as WE all know wasn't designed for Ethanol. Get a kit a rebuild just like those Carter's on the Kohlers.

[RandyLittrell 3,884]

I think I would treat it just like our tractors. Sounds like it takes awhile for the fuel to reach the carb so I would check fuel lines, pump and filter before I messed with replacing the carb. 

 

 

Randy

[lynnmor 7,315]

2 hours ago, Maxwell-8 said:

Do they have return valves?

 

Maybe a bad gastank vent? Building up some vacuum in the gastank

 

No, I don't know of a carburetor ever made that returned gasoline in the float bowl back to the tank.  What I suspect is the carburetor in this thread is leaking down slowly and that gas is going into the engine and probably down into the oil.

[WVHillbilly520H 10,373]

My old C30 sits many weeks without getting started lots of cranking to finally get it fire off, I do believe the original (1979) manual lever pump is slowing dying (diaphragms going bad) I have already rebuilt the carb better but still not good after sitting, I will either replace said pump and or add a small electric pump to help feed the carb, my Malibu also sets long between firing and it only has a high performance Holley style electric fuel pump turn then key listen to the pump change sound pump the carb 2-3 and fires right off, bear in mind it also has no choke/choke tower for maximum power.

Edited February 1, 2021 by WVHillbilly520H

[Maxwell-8 4,277]

1 hour ago, lynnmor said:

 

No, I don't know of a carburetor ever made that returned gasoline in the float bowl back to the tank.  What I suspect is the carburetor in this thread is leaking down slowly and that gas is going into the engine and probably down into the oil.

OOHHH Oil roulette: i have blown up one engine in my life: carb leaked fuel in the oil, therefor making the oil to thin, destroyed it pretty fast.

[squonk 41,164]

1 hour ago, lynnmor said:

 

No, I don't know of a carburetor ever made that returned gasoline in the float bowl back to the tank.  What I suspect is the carburetor in this thread is leaking down slowly and that gas is going into the engine and probably down into the oil.

Not the carb itself but the pump with a return and a bad ck valve can have a siphon start up and suck the fuel back out of a carb. I know pretty far fetched but I had this happen on a motorhome with a Chysler 440

[ebinmaine 67,695]

8 minutes ago, squonk said:

Not the carb itself but the pump with a return and a bad ck valve can have a siphon start up and suck the fuel back out of a carb. I know pretty far fetched but I had this happen on a motorhome with a Chysler 440

I've seen it in 70s GM as well. 

[WVHillbilly520H 10,373]

6 minutes ago, squonk said:

Not the carb itself but the pump with a return and a bad ck valve can have a siphon start up and suck the fuel back out of a carb. I know pretty far fetched but I had this happen on a motorhome with a Chysler 440

Doesn't look to be a third fitting on the pump but I am not For guy.

[lynnmor 7,315]

2 hours ago, WVHillbilly520H said:

My old C30 sits many weeks without getting started lots of cranking to finally get it fire off, I do believe the original (1979) manual lever pump is slowing dying (diaphragms going bad) I have already rebuilt the carb better but still not good after sitting, I will either replace said pump and or add a small electric pump to help feed the carb, my Malibu also sets long between firing and it only has a high performance Holley style electric fuel pump turn then key listen to the pump change sound pump the carb 2-3 and fires right off, bear in mind it also has no choke/choke tower for maximum power.

 

You may have had QuadraJet carburetors, they have a very small fuel bowl and it doesn't take long for that small amount of fuel to evaporate.  Also, QuadraJets were prone to leaking below the jet wells, these seals helped with that. 

 

An electric fuel pump will result in much faster starts, just as they will on a Wheel Horse.  There is one downside to that, extra cranking gets the oil circulating before firing albeit at the expense of the starter.

 

[elcamino/wheelhorse 9,326]

@ebinmaine  Would that be a computer controlled carb like GM had in the 80's. If so a 50 cal. would help it. Nothing else. If my El sits for a few days , it takes for ever to get it to start. 

[WVHillbilly520H 10,373]

43 minutes ago, lynnmor said:

 

You may have had QuadraJet carburetors, they have a very small fuel bowl and it doesn't take long for that small amount of fuel to evaporate.  Also, QuadraJets were prone to leaking below the jet wells, these seals helped with that. 

 

An electric fuel pump will result in much faster starts, just as they will on a Wheel Horse.  There is one downside to that, extra cranking gets the oil circulating before firing albeit at the expense of the starter.

 

With the Malibu I have switches for fuel and ignition, so crank without both for oil pressure to build then light off both and fires away, the C30 is still basically bone stock.

[Stepney 2,325]

A carb in 87 on a v8?? I thought only the 460 remained carb but that is an odd era for Ford.

I'm partial to Carter/Holley carbs.

But .. unless there's something really really wrong, a good soak and a kit should have it working, no? I wonder if its set up properly at all. Manual choke tends to just be a mask for other issues in my findings. My Carter 300 fires up no trouble after sitting for weeks in the freezing cold.

Wish it was closer so we could have a peek. So hard to figure what an engine is doing in words..

[ebinmaine 67,695]

3 minutes ago, Stepney said:

A carb in 87 on a v8?? I thought only the 460 remained carb but that is an odd era for Ford.

I'm partial to Carter/Holley carbs.

But .. unless there's something really really wrong, a good soak and a kit should have it working, no? I wonder if its set up properly at all. Manual choke tends to just be a mask for other issues in my findings. My Carter 300 fires up no trouble after sitting for weeks in the freezing cold.

Wish it was closer so we could have a peek. So hard to figure what an engine is doing in words..

Maybe come spring that will turn into an overnight road trip and we can camp at the lake across the street...

[WVHillbilly520H 10,373]

Another thing with that era vehicles and carburetors, a dozen too many vacuum lines and switches, as they harden and shrink cracking and pin holes or broken plastic hose fitting/barbs, just a myriad of possibilities, but I'm still gonna go with the 2 mechanical parts Carb rebuild and fuel pump, then the vacuum lines and maybe even a proper tune-up plugs wires cap and rotor button ect. Even using RockAuto you can buy O.E. Motorcraft replacements... Just trying to help you out, if you can master 1 cylinder the other 7 ain't that bad.