Topic: My Gasket Has A Hole In It -

[jwc66k]

And did it. For many moons I could smell gas from my 65 GT Fastback after a run around the block and much to my dismay, could not figure out where it was coming from. Last Thursday I need to move the car. It would not start. I opened the hood, remover the air cleaner and was shocked, shocked I tell you, to see gas flowing from the accelerator pump. I stuffed some rags in the manifold to collect the gas and went for some tools (a screw driver). By the time I got back the flow had stopped, it either repaired itself, or was empty. I removed the accelerator cover and found this. The gasket was missing some gasket in a lot of places (see picture - the light coming thru tells the story). I had another one in a junk box labeled "Carburetor" and I was in the process to installing it when I noticed the holes didn't line up. The 4100 gasket's holes were in a square pattern, this one's hole were in a rectangular pattern, close but some "adapting" was required. Using a 3/16 inch hole punch, I "moved" the holes to a more acceptable square pattern and installed it. This entire exercise took about 30 minutes. I don't know where the replacement came from but it works fine. Oh, the car is 50 years old on 5/11/2015 (that's tomorrow). It's a 1965 GT Fastback with and I have the window sticker to prove it. There's 110,000 miles on the odometer and to the best of my knowledge, the engine, and carburetor, have never been apart.
This brings up a question - is there a source to purchase just the accelerator pump gasket?
Jim
A slight change, it's a diaphragm, and it's available from Amazon -
http://www.amazon.com/Dorman-HELP-90082-Accelerator-Diaphram/dp/B000CO7IS6/ref=sr_1_22?s=automotive&ie=UTF8&qid=1431318717&sr=1-22&keywords=accelerator+pump+diaphragm
- for $4.99 and free shipping if you order at least $35 worth of stuff.
Remember the Dorman number 90082 if you go shopping locally. Dorman will swing a deal and sell you one for $12.55. Such a deal. 

[suskeenwiske]

If the Carburetor has never been apart, a whole kit may be in order, especially since the disintegrating Accelerator Pump particles may have lodged within some of the passages. At the very least, make sure that the small Red/Orange Check Valve behind the Accelerator Pump is in good condition.

Ray

[midlife]

I wonder if the ethanol-added-to-gas may have been a factor...

[Toploader]

I wonder if the ethanol-added-to-gas may have been a factor...

+1. Call it the e-gas 

Nice ride by the way.

[67gtasanjose]

I wonder if the ethanol-added-to-gas may have been a factor...

Replacement carb parts are available these days that will not be affected by today's gasolines. The original parts not so much so.

[jwc66k]

If the Carburetor has never been apart, a whole kit may be in order, especially since the disintegrating Accelerator Pump particles may have lodged within some of the passages. At the very least, make sure that the small Red/Orange Check Valve behind the Accelerator Pump is in good condition.

The rebuild kit just arrived. The check valve was in good visible condition and the car ran very good with the kluge diaphragm.

I wonder if the ethanol-added-to-gas may have been a factor...

That and a long time sitting in the California heat, even in my garage.  At one time I had six other Mustangs and getting them on the road even monthly was difficult. A long time friend who is a retired carburetor rebuilder saw the diaphragm and thought that as it was "stiff" that old age may have been part of the problem.

+1. Call it the e-gas 
Nice ride by the way.

It's a California feature, less gas replaced by corn juice for more money. 
Thanks for the comment on the ride. The car has been featured in eight different calendars since 2000, twice on the cover. The photographer is Ron Kimball - http://www.kimballstock.com/ Check out his portfolio.

Replacement carb parts are available these days that will not be affected by today's gasolines. The original parts not so much so.

How true. I've replaced the fuel lines on all my other cars, this one is next.
Jim

[drummingrocks]

I need to do this on my '67 coupe (289 2V).  I've got the same problem; after I drive it and it sits for a few minutes, the gas fumes are awful.  And since I park the car in the basement underneath the house, the fumes have a nasty habit of wafting up into the house when they're really strong.  Not good.

I swapped the power valve last weekend, thinking that might've been the problem.  At the time, I found some trash inside the bowl and thought that maybe it was clogging the needle-and-seat, and making it hang up.  To make a long story short, I thought I had the problem fixed, but I drove the car yesterday and noticed gas fumes soon after.  I guess I'll try replacing the accelerator pump next.

[WT8095]

I need to do this on my '67 coupe (289 2V).  I've got the same problem; after I drive it and it sits for a few minutes, the gas fumes are awful.  And since I park the car in the basement underneath the house, the fumes have a nasty habit of wafting up into the house when they're really strong.  Not good.

I swapped the power valve last weekend, thinking that might've been the problem.  At the time, I found some trash inside the bowl and thought that maybe it was clogging the needle-and-seat, and making it hang up.  To make a long story short, I thought I had the problem fixed, but I drove the car yesterday and noticed gas fumes soon after.  I guess I'll try replacing the accelerator pump next.

Keep in mind that mechanical fuel pumps have the same type of diaphragm. If your acc pump isn't the source of the fumes, check out your fuel pump. When the pump is positioned above the mounting flange, leaking fuel can get into the oil pan. I don't know if any Mustangs were ever equipped with the upwards-facing kind.

[suskeenwiske]

As strong as the smell of the vapor is, there should be an obvious area of liquid fuel on the engine, the floor, at the gas tank, etc. Until the problem is found, I would park outside the house; trapped vapor ignition can be devastating and at the very least the vapor can cause breathing problem, headaches and other health issues.

Unless you're very mechanically inclined, a trip to your local mechanic may be your best bet.

Ray

[WT8095]

As strong as the smell of the vapor is, there should be an obvious area of liquid fuel on the engine, the floor, at the gas tank, etc. Until the problem is found, I would park outside the house; trapped vapor ignition can be devastating and at the very least the vapor can cause breathing problem, headaches and other health issues.

Unless you're very mechanically inclined, a trip to your local mechanic may be your best bet.

Ray

Excellent suggestions, Ray. If it's that bad, it's risky to even start it - push it out, then get someone to come take a look at it. If it were mine, I would disconnect the battery, too.