hello,
so try to keep it short, its 79 ford f150, 351 cleveland. motorcraft 2150 carb. so while going up a hill it losses power until it stalls, then when restart, takes like 60secs to rebuild rpms to full power again. but i can go up same hills in reverse with no problem, or loss of power?
i pulled to carb to rebuild, but found brand new one for cheap so its a brand new 2150 on it now, stock settings on carb, didnt touch anything out of box. and exact same issue. (fyi,, truck is driven between 7000 -8000ft altitude if that matters) and when i say hill, not like im hillclimbing it! just normal mountain roads here, so yes, decent grade, but not offroading.
do i need to adjust float? what height? air/fuel mixture screws? i put a fuel cell in bed, to eliminate all lines and tank. same problem. put on electric pump, bypassed mechanical pump, and it got a little better, didnt stall, but still major power loss as i climb hill.

(also fyi,,to try and solve i have put on new dizzy,cap,rotor,coil,plugs, wires)

thanks

 

You may want to look into buying a new fuel pump. Sounds like she's getting a little weak.

Edit: Nevermind... just read everything... What psi is the pump pushing and also how many gallons per minute because stock is 8 psi with 45 gpm I think.

 

yes, seems like thats the issue. i did buy new mechanical pump, still did same thing, and as i said i bought new electric pump and ran new line to by pass all old lines and tank, etc... and problem did get better,, but still major power loss on hills?

thanks

 

How's your fuel filter looking? Screen in the fuel tank? Are you sure you don't have any obstructions in the lines?

 

new filter..and liek i said, not using any old lines, or tank.. put cell in truck bed, and ran new line right to filter then into carb,,,so i could eliminate all the old lines, tank, etc...

thanks

 

I'd take your float level up just a hair, then try again.

 

ok.. so up a hair...now i have to bend that little part to raise it, no easy adjustment for that, correct?

 

When you stomp on it does it do the same thing? Or is it just hills?

 

and the reason i am focused on a carb issue is because how it seems fine while going uphill in reverse?? just sucks going forward?

thanks again

 

I'm now having a similar issue, seems to be mostly at lower speeds, and yes JFK, if I stomp on it, it does that too, but if I try to duplicate this in Park, it doesn't happen, I set timing back to 6*BTDC, as Ford recommends on the sticker, and it still happens


1979 F150 351M


what is your theory on this issue ?

 

This thread is 3.5 years old.....I think the OP might have gotten it fixed by now.....

Your situation: the 351M/400 likes 10* - 12* BTDC as stated on one of my old valve covers. Try bumping your timing up to that. Is your engine fully smog endowed?

Losing power under load could be a carb (accelerator pump, too lean a mixture setting) problem, timing, or vac advance. How's your vacuum advance can? Not a shot diaphragm or sticky mechanism? I would check yer vac advance for problems.

 

I know the thread is old, it came up in a search for my situation


I had it set at 10* BTDC, that's when the stall and hesitating started to happen, so I set it back to Factory specs, and "smog endowed?" I really don't know, it has valve to carb vacuum, no Cat


how would I check the Vac Advance

 

Pull the distributor cap and rotor....pull the vacuum line from the carb leaving it attached to the Vac can. Or attach a hose to the vac can nipple and apply vacuum to it. Watch the advance arm inside the distributor to see if there's any movement - it should move ~ 0.50" toward the front of the vehicle when vacuum is applied and move back when vacuum is taken away.

No moment = bad diaphragm in the vac advance can and time to replace it.

Smog endowed = a plethora of vacuum lines all over the place, EGR, vacuum switches, etc.

 

well, it seems I've found my Distributor Vacuum Advance is hooked up to the Full Vacuum Manifold Port, and my Timed Spark Vacuum Source is capped off, (Holley 4160) its been this way since I got the truck almost 2 1/2 years ago, I'll fix that this weekend, but do you think I may need to reset the Distributor ? also thinking of a Carb rebuild

 

If the timing was set right - vac. adv unplugged and capped - you wouldn't have to re-set it. It would be a good idea to recheck it anyway and set it to where she should be ~ 12* BTDC.

What would need to be reset is your carb settings...curb idle and mixture settings. Hopefully you have a vacuum gauge to use. Do the timing first then carb adjustments.