351c starting & driving issues

Help Support 7173Mustangs.com:

n_reckless

Well-known member
Joined
Oct 18, 2018
Messages
78
Reaction score
4
Location
JAX, FL
My Car
'72 Mach 1
[url=https://ibb.co/n0k1tJg][img]https://i.ibb.co/xs5gdTC/42440948-10216406433904294-5071779102906646528-n.jpg[/img][/url]
I just got my rebuilt Mach 1 back with a 351c 2v. 

I don't know the condition of the car before the rebuilt because I bought it with a rod knock so I don't have any comparisons between the before and after condition so probably I have more issues than the engine what's already done.

The engine have an electric distributor from a later Ford model...I don't know what it is..it was probably the previous owner....carb is the same, not the best, that's all I know, and the guy who checked the car after the rebuild said the fuel pump isn't too good. I have a manual choke.

After i got the car back the engine stopped after the first red sign when i tried to move at the green light.

Next morning is the same: I could start the engine after 2 or attempts playing with the choke then I stalled again leaving the neighborhood.

I noticed two things: If I let the engine run a lil'bit before putting in gear it's better. If I hit the gas really gently it's fine but If I try to start and hit the gas even a little but harder the engine also stops. And sometimes while driving on low speed it feels like it's not getting enough gas...

What I think and want to do is replacing the carb (or check it's accelerator pump?), upgrading the fuel pump and getting a better distributor, wiring, ignition box etc.

It'd be my daily driver and I have no other car so I try to get everything done asap. 

Is there anything I have to check or is it a good starting point?

 
Last edited by a moderator:

Don C

Fords Forever
Joined
Jan 1, 2012
Messages
8,112
Reaction score
872
Location
Springfield, OR
My Car
1971 Mustang Sportroof M code
Yes, you have a good starting point. I would start with rebuilding the carburetor and would also check the timing and for vacuum leaks. How old is the fuel?

 

Vinnie

Project manager "Project AmsterFoose"
Joined
Nov 7, 2013
Messages
1,520
Reaction score
143
Location
Amsterdam, The Netherlands
My Car
1973 Mustang Grande 351C 2V, built on the very last production day (July 6, 1973) for Grande's.
Doesn’t sound like a fuel pump issue. I’d focus on carb and ignition. What happened with the stock distributor? They work great upgraded with a pertronix module.

Vincent.

 

n_reckless

Well-known member
Joined
Oct 18, 2018
Messages
78
Reaction score
4
Location
JAX, FL
My Car
'72 Mach 1
[url=https://ibb.co/n0k1tJg][img]https://i.ibb.co/xs5gdTC/42440948-10216406433904294-5071779102906646528-n.jpg[/img][/url]
Fuel is fresh, we just filled it after the rebuild. Timing is ok. I don't know what happened the stock distributor. Probably it was the previous owner. But unfortunately I don't know him and the cars background because I bought it from a dealer. Since the carb is not original aftermarket (i don't know what it is) and has some issues I wouldn't mess with the rebuild. I'd buy a new one because I need to get it run right asap.

 
Last edited by a moderator:

kcmash

VIP Members
Joined
Sep 2, 2012
Messages
1,466
Reaction score
100
Location
Blue Springs, MO
My Car
1971 Mach 1, Grabber Blue w/Argent stripes. Original 2V 351C Auto, Tilt, rear defog, Black Comfortweave Interior. Under restoration. Original colors, 4V 351C, 4-Speed, Spoilers, Magnums, Ram Air. All Ford parts.
Sounds like a carb issue to me.  A 351C -2v in stock form should be a very stable running and accelerating engine in your car.

The Accelerator pump is an easy one to check.  With the car off and the air cleaner removed, look down the throat of the carb and pump the throttle with your hand.  You should see very solid streams(left and right) shooting into the carb venturi area.  If not, you either have a bad pump diaphragm, clogged ports, or a poorly adjusted accelerator pump.

A bad accelerator pump will make the car stumble when you try to quickly rev the engine from idle, and during takeoff from stops.  It typically won't cause it to stall while stopping, but when trying to take off it can stumble and die.

I assume from your post that the rebuild shop for your engine did NOT start it for you, break it in or rebuild the carb for you.  The problem we all face these days is the gas formulation at the pump.  The newer gasoline uses ethanol which evaporates in an atmospheric environment (Like a carb since the gas in the float bowls can evaporate)   The gasoline does better in fuel injected system since the fuel is under pressure at all times in the fuel line.  It tends to not evaporate.  

Why the boring details?  It is easy for a "perfectly good" carburetor to go bad on the shelf when gas evaporates even over a few weeks.  When the gas evaporates it leaves a varnish like residue that can clog little ports like the accelerator pump ports or the check ball assembly.  

If you suspect the sitting carb is a problem. or even if you want to try something easy, try running a can of Sea Foam through the system to see if it breaks things loose.  Total cost about $9 for the Sea Foam, and you have anb excuse to drive the car just to burn a tank of gas.  If that doesn't work magic for you.  Do the carb kit, but to be sure to clean all the ports in the carb with Berryman Chem tool, or another good carb cleaning and de-gumming solvent.

kcmash

 

n_reckless

Well-known member
Joined
Oct 18, 2018
Messages
78
Reaction score
4
Location
JAX, FL
My Car
'72 Mach 1
[url=https://ibb.co/n0k1tJg][img]https://i.ibb.co/xs5gdTC/42440948-10216406433904294-5071779102906646528-n.jpg[/img][/url]
Yes... they didn't fire the engine up just did the rebuild. 

My engine isn't stall while stopping but when I try to take off e.g. after a red light sometimes it stalls. But only when I forgot to pay attention and hit the gas a little harder. And I'm not talking about flooring it when I don't pay attention. But this is the 3rd day I'm driving it and I can handle it if I play with the gas and keep my eyes on it. But of course it's not normal and have to solve this issue. 

First replacing the carb and distributor, spark plug wires. Then see what happens.

 

Hemikiller

Tech Advisors
Staff member
Moderator
Joined
Jul 12, 2010
Messages
3,563
Reaction score
771
Location
Killingworth, CT
My Car
71 Mach 1
65 coupe
Sounds simply like your accelerator pump isn't working. Could be a bad diaphragm ($3 at the parts store) or the linkage needs to be adjusted.

 

clevelandcoupe

VIP Members
Joined
Jul 3, 2011
Messages
686
Reaction score
26
Location
Northwest Jersey
My Car
1973 Mach 1 original 351C C6 Now 460-4spd top loader
1930 Ford Model A 351C-AOD
Unfortunately, it seems a little alarming that the shop that completed the "rebuild" did not fire up the engine or wanted to be involved. With the current issues with oils, additives, etc with cam and lifters especially, I hope your motor was broken in properly.......

Thanks, Jay

 

Hemikiller

Tech Advisors
Staff member
Moderator
Joined
Jul 12, 2010
Messages
3,563
Reaction score
771
Location
Killingworth, CT
My Car
71 Mach 1
65 coupe
I just had a chance to check the carb. That's a Weber (what supposed to be an Edelbrock I guess) and 8867 stamped on it.
Weber made the carbs for Edelbrock for a time. The actual carb ID number is stamped on one of the front mounting lugs. Been a while, don't remember if it's driver or passenger side. Numbers are usually 1406, 1407 etc.

 

Danoh1

VIP Members
Joined
Jan 3, 2019
Messages
86
Reaction score
15
Location
Central Texas
My Car
72 Q Code barn find, 72 R code project
Quick fuel “brawler” carb for under 400 bucks. Works almost perfect out of the box.

I’ve quit rebuilding old carbs unless numbers matching. The new ones are far better. The brawler has 4 corner idle, 2 metering blocks, adjustable air bleeds, electric choke, adjustable secondary spring. It’s really a nice piece.

I just did a 351W for a friend. I rebuilt the old Holley. It worked fine. He couldn’t grasp the manual choke concept. Put a brawler on and the car is better. I had a slight off idle stumble that was cured with raising the idle an going a little richer on the idle.

A bog off idle at a traffic light is usually idle and mixture. The accelerator pump system shouldn’t be doing much.

 

n_reckless

Well-known member
Joined
Oct 18, 2018
Messages
78
Reaction score
4
Location
JAX, FL
My Car
'72 Mach 1
[url=https://ibb.co/n0k1tJg][img]https://i.ibb.co/xs5gdTC/42440948-10216406433904294-5071779102906646528-n.jpg[/img][/url]
I've already ordered a 600cfm Classic Holley with manual choke. I'm fine with manual and based on the reviews it's pretty reliable for street. The only thing is the non-adjustable floats. I'd only use the car for street/daily and the guys at Holley told that 600cfm is pretty much enough. I already have an MSD pro billet distributor, new wires etc and we'll install it on Monday so we can see how it'll perform. 

 

kcmash

VIP Members
Joined
Sep 2, 2012
Messages
1,466
Reaction score
100
Location
Blue Springs, MO
My Car
1971 Mach 1, Grabber Blue w/Argent stripes. Original 2V 351C Auto, Tilt, rear defog, Black Comfortweave Interior. Under restoration. Original colors, 4V 351C, 4-Speed, Spoilers, Magnums, Ram Air. All Ford parts.
Quick fuel “brawler” carb for under 400 bucks. Works almost perfect out of the box.

I’ve quit rebuilding old carbs unless numbers matching. The new ones are far better.  The brawler has 4 corner idle, 2 metering blocks, adjustable air bleeds, electric choke, adjustable secondary spring. It’s really a nice piece.

I just did a 351W for a friend.  I rebuilt the old Holley.  It worked fine.  He couldn’t grasp the manual choke concept.  Put a brawler on and the car is better.  I had a slight off idle stumble that was cured with raising the idle an going a little richer on the idle.  

A bog off idle at a traffic light is usually idle and mixture.  The accelerator pump system shouldn’t be doing much.
"A bog off idle at a traffic light is usually idle and mixture. The accelerator pump system shouldn’t be doing much."  Danoh1  I respectfully disagree with this statement. 

 The whole purpose of the accelerator pump circuit is to provide additional fuel to accelerate from idle.  If you try to adjust that out with the idle mixture you will be running too rich and load up at idle.  If he were dying when just idling in gear I would agree that the idle settings were the problem, but when he says he can pay close attention and get it to keep running off idle, I feel that is a classic accelerator pump symptom.

kcmash  

 
Top