All Small Six Mustang is eating fuel pumps

This relates to all small sixes
J

jonathon.t.mcmahon@gmail.

New member
Hey lads -

'67 Mustang 200ci. Motor was rebuilt about 1 or 2 thousand miles ago. Running a rebuilt Holley 1940.

It has eaten 4 mechanical pumps in the past year. Mostly replacing with Carter models with both the integrated filter from '65-'66 models and the normal part for '67.

I use only non-ethanol fuel.

Any thoughts before I throw in the towel and move to an electric pusher? While I am pretty good at swaping them out roadside, it's not very fun to lose the throttle while driving.

Edit: tank and sending unit both new.
 
Last edited:
jonathon.t.mcmahon@gmail. said:
Hey lads -

'67 Mustang 200ci. Motor was rebuilt about 1 or 2 thousand miles ago. Running a rebuilt Holley 1940.

It has eaten 4 mechanical pumps in the past year. Mostly replacing with Carter models with both the integrated filter from '65-'66 models and the normal part for '67.

I use only non-ethanol fuel.

Any thoughts before I throw in the towel and move to an electric pusher? While I am pretty good at swaping them out roadside, it's not very fun to lose the throttle while driving.
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Clogging, or mechanical damage?
 
They where junk 50 year go, Went electric, no problem after that.
I am assuming that when you say ate, you mean it is not eating the arm .
 
Yeah, it kind of depends on why they are failing. I can’t imagine the diaphragm failing so fast on that many fuel pumps but if you have a lot of debris in your tank, I could see that clogging the pump. I’m using a stock pump on mine with zero problems at the moment but my last three project cars had Carter electrical fuel pumps with fuel pressure regulators. I would drain the tank and make sure the pump isn’t getting full of debris. It doesn’t make sense that you would have 4 mechanical pumps go south in that short a time.
 
awasson said:
Yeah, it kind of depends on why they are failing. I can’t imagine the diaphragm failing so fast on that many fuel pumps but if you have a lot of debris in your tank, I could see that clogging the pump. I’m using a stock pump on mine with zero problems at the moment but my last three project cars had Carter electrical fuel pumps with fuel pressure regulators. I would drain the tank and make sure the pump isn’t getting full of debris. It doesn’t make sense that you would have 4 mechanical pumps go south in that short a time.
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Thanks. Yea tank and sending unit is new.
 
Have you seen the labor pool lately. If a machine is not making the whole thing it will be junk. Got to get back to the phone, can't miss anything. Or most likely made by children in a land far far away. The diaphragm is probably made out of soy bean oil.
 
I've been using the O'Reilly Auto Parts replacement units for years and have had absolutely no trouble at all with them.
 
jonathon.t.mcmahon@gmail. said:
Mechanical. The last two I pulled out, a couple of small metal bits of the arm were sheared off.
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That's weird but not unheard of. I can't imagine that there is any way you could have gotten the tongue on the wrong side of the cam but maybe the cam itself is to blame; maybe it's forcing the lever beyond it's range of movement. I think it might be time to make a block off plate and just grab an electric fuel pump and a regulator. You'll never have to deal with the mechanical one again.
 
jonathon.t.mcmahon@gmail. said:
I did have metal bits of the arm the last two times. So, more eating than failing if that makes sense.
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It's possible that by now the camshaft lobe is roughed up enough to be ruined. IDK, since the pump load is a fraction of the lifters. But with lifters any cam irregularity = no good. Might want to get a mirror and look at the cam lobe to see it's condition. Tip: hold the flashlight on the same plane your head at eye level, the mirror will shine the light on the object reflected. Works better than trying to shine into the hole directly. A head-strap light works well also.
I'll vote with awasson and say- might be time to go electric. You don't want accumulating metal debris internally!
 
One other idea-check the pushrod and make sure that it is the right one, or more specifically, the right length. I ran into the same problem with my Formula Vee car after I purchased it. Research revealed that VW used two different fuel setups-one for engines with alternators, and one for generators. The length of the pushrods has an 8mm difference and must be matched to the proper pump, and the dumbass PO had a long pushrod instead of the shorter one and it was breaking the arm on the pump.

What I'm getting at is that, if you didn't build the engine, there's no telling what's in it.
 
Even the Carter pumps aren't the quality they should be. They seem to be reboxed btw. Put one on about two months ago and was getting over 15psi to the carb. It got returned. Ordered an electric one from Pegasus racing, (thank you 63Sprint for pointing them out) and as much as I dislike the annoying sound of an electric pump I feel like it was the best thing for the old truck. Immediate cold starts, correct fuel pressure and greater reliability.
 
sixtseventwo4d said:
Even the Carter pumps aren't the quality they should be. They seem to be reboxed btw. Put one on about two months ago and was getting over 15psi to the carb. It got returned. Ordered an electric one from Pegasus racing, (thank you 63Sprint for pointing them out) and as much as I dislike the annoying sound of an electric pump I feel like it was the best thing for the old truck. Immediate cold starts, correct fuel pressure and greater reliability.
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I'm tempted to over spend on new old stock to see but agree the quality is not good at the moment.

I'll look into Pegasus - thanks!
 
Kritas said:
One other idea-check the pushrod and make sure that it is the right one, or more specifically, the right length. I ran into the same problem with my Formula Vee car after I purchased it. Research revealed that VW used two different fuel setups-one for engines with alternators, and one for generators. The length of the pushrods has an 8mm difference and must be matched to the proper pump, and the dumbass PO had a long pushrod instead of the shorter one and it was breaking the arm on the pump.

What I'm getting at is that, if you didn't build the engine, there's no telling what's in it.
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Very helpful, thank you.

Debating digging into the motor for the correct solve or just moving on to electric.
 
drag-200stang said:
When it comes to the fuel pump mounting and working the small six are all the same, there is no pushrod, the arm on the pumps you are getting may be wrong. Other than the cam made wrong or worn off, there is nothing one could do wrong to effect the fuel pump other than putting the pump upside down.
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Thanks for straightening me out on this. I haven't swapped out a fuel pump on my Ford six yet and assumed it had a pushrod like all my other cars.

Next you'll tell me that a Mustang lacks a flux capacitor.
 
drag-200stang said:
When it comes to the fuel pump mounting and working the small six are all the same, there is no pushrod, the arm on the pumps you are getting may be wrong. Other than the cam made wrong or worn off, there is nothing one could do wrong to effect the fuel pump other than putting the pump upside down.
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I'm not going to try but think it will even go in upside-down.

I've gotten V8 pumps on shipping errors before. Arm is much different/ obvious.

Narrows me down to $hit parts or a cam issue.
 
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