Accelerator Pump issue

[DanOlson]

Got the 53 out the other day after almost 6 months in storage. Was really happy when it started without having to prime it first. It seems that for the last five years or so the accelerator pump does not work in the spring and I end up replacing it. This year is no exception. Pulling away from a light or stop sign is bit of an art. Could the high quality fuel of today be drying it out or attacking it in some way? Nothing serious but just a PITA.

Dan

[Young Ed]

Maybe your carb is going dry over the winter and its drying out? I've had similar issues with my truck but I just ignore it and it seems to go away. I've also wondered if its just the fact I'm running on 6month old fuel

[greg g]

Pretty easy to check the condition of the leather plunger piece. But like Ed said it probably dried out during storage and may seal better once it gets some gas around it. If not George Asche has the acc pump piston assembly for not too much money.

Don't kow if they are available from NAPA or the like outside of the rebuild kit.

[Young Ed]

Don't kow if they are available from NAPA or the like outside of the rebuild kit.

Before Napa revamped their site I was able to find the accel pump solo. I have the part # for it at home somewhere or a forum search may turn up a post from me with the # in it.

[Dave72dt]

Seems like every time they redo their site it becomes less user freindly.

[Don Coatney]

I assume you all know to soak the accelerator pump leather in oil (overnight) prior to installing them.

[DanOlson]

I THINK I soaked it but certainly not overnight. It's coming apart tonight and into oil.

[Young Ed]

Don I've never soaked one. Doesn't the oil all just wash off after a little use?

[Don Coatney]

Don I've never soaked one. Doesn't the oil all just wash off after a little use?

All I know is when I have soaked them in oil I have not had to touch them again for several years.

[Young Ed]

I was taught to soak them in spit for about 1 second before installing them. I haven't had any issues with mine either. Just give them a slurp like a lollypop and install. Not reccommended on used ones!

[JBNeal]

I recall reading in an old shop manual that leather seals do not work properly unless soaked in light oil (24 hrs). On rotating shaft seals, the oil should be worked into the leather with a polished metal cylinder, such as a clean wrench socket or philips screwdriver. Once the oil saturates the leather pores and causes the leather to expand, it takes a great deal of effort to remove that oil. The accelerator pump is no exception, as the seal is in a bore and the seal sees very little surface contact with gasoline. I reckon there is a surface tension component that is also at work with regards to these fluids, as the oil & gasoline would interact little because of the low surface area involved.

[Don Coatney]

I recall reading in an old shop manual that leather seals do not work properly unless soaked in light oil (24 hrs). On rotating shaft seals, the oil should be worked into the leather with a polished metal cylinder, such as a clean wrench socket or philips screwdriver. Once the oil saturates the leather pores and causes the leather to expand, it takes a great deal of effort to remove that oil. The accelerator pump is no exception, as the seal is in a bore and the seal sees very little surface contact with gasoline. I reckon there is a surface tension component that is also at work with regards to these fluids, as the oil & gasoline would interact little because of the low surface area involved.

I thought I read that somewhere but I did not recall where. Thanks for posting.

[John-T-53]

I recall reading in an old shop manual that leather seals do not work properly unless soaked in light oil (24 hrs). On rotating shaft seals, the oil should be worked into the leather with a polished metal cylinder, such as a clean wrench socket or philips screwdriver. Once the oil saturates the leather pores and causes the leather to expand, it takes a great deal of effort to remove that oil. The accelerator pump is no exception, as the seal is in a bore and the seal sees very little surface contact with gasoline. I reckon there is a surface tension component that is also at work with regards to these fluids, as the oil & gasoline would interact little because of the low surface area involved.

This is the same procedure specified for the differential pinion seal, and any other seals that used to moo. I used 10 wt and the old cow seemed to like it.

[DanOlson]

Okay, I'm home with the top of the carb off and the pump works perfect when manually pressed down. I may have a missing part. What actuates the accelerator pump? The lever (link - pump connector) slides up and down the pump shaft but does not push down the pump.

Confused.

[greg g]

open the link and go to figure4. 5, and 6

http://oldcarmanualproject.com/manuals/Carbs/Carter/BB-downdraft/1939up/pages/p_%2057_jpg.htm

[DanOlson]

Looking at the attached list, what I don't understand is how #17 (Plunger and Rod assy) gets pushed down. When operating the throttle #18 (link - Pump operating slides up and down #17.

Whoa, I just though of something. Theres's a notch about half way down on #17 that the bottom of #20 (Spring) should catch on providing tension so that when #18 goes down it pushes on #19 and the spring pushing the pump down.

I don't see that I'm missing any parts so it must be installed incorrectly.

[Young Ed]

When you install the plunger you have to twist it 90° to lock it into place. Then when 43 and the little arm 16 pull down it operates the plunger.

[DanOlson]

Turn 17 90 degrees to lock into place with 18?

[Young Ed]

Ya believe thats what it does. I know you have to turn the accel pump to make it lock. There are notches in it about 1/2 way down that allow it to turn.

[DanOlson]

Hmmm..... Thought I tried that but I'm going to have to go back home and check. Planning on doing the Pine Island cruise in tonight if I can get it fixed.

[Young Ed]

Dan gimme a call and I can pull apart one of my spare carbs to check. I'll be home 3pm.

[DanOlson]

After watching a video about adjusting the accelerator pump on the Carter BB,

http://www.carburetor-parts.com/Carter_BB_Carburetor_Accelerator_Pump_p/64-360.htm

I see a big difference with the spring. Mine appears to be really compressed compared to the one in the video. Wonder if someone changed the spring or squeezed it together.

I'll stretch it after work and give it a whirl.

[DanOlson]

Stretched out the spring to about 2x it's normal length and now has the umph to push a really snug accelerator pump down. I had to add an additional return spring on the throttle to get it back to an idle. I'm sure it will wear itself in and loosen up a bit.

Thanks Ed for taking a carb of yours apart to compare notes over the phone.

Of all the forums I belong to, this one is by far the most helpful and fun.

[greg g]

The spring is actually what pushes the plunger down. When you shut the throttle the linkage raises it back into the ready position. the spring dampens the stroke so the squirt provides a fairly consistant flow throughthe stroke rather than one the give a big jolt then peters out. Stretching the spring will make it more responsive but it will also keep it from returning to the fully at rest postion.

But if you are happy with the way it is workig leave it alone.

[DanOlson]

Ordered up a carb kit and replaced the accelerator pump. Soaked it in oil overnight and finished putting it together at 5:45 this morning in my bathrobe so I could drive it to work. The new pump fits much better. I compressed the spring back to where it was and life is good. I don't recall if the old pump always fit so tight or if it swelled over time (1 year).