Corvair DiagramCorvair Photo
Corvair Center
home forum corvairs calendar links Corvair Podcast
California Corvairs
Clarks Corvair
Clarks Corvair
“CORSA"



Chevy Corvair License Plate
Chevy Corvair Chrome Wheel
Corvair Center Forum :  Corvair Center Phorum The fastest message board... ever.
Corvair Center 
Pages: 12Next
Current Page: 1 of 2
Carb not spraying properly from accelerator pump
Posted by: Six Gun Joe ()
Date: June 19, 2021 10:14AM

I have an automatic '64 Monza with a '62-'63 98HP engine and '64 carbs.

I discovered recently that one carb has a good stream from the accelerator pump but the other does not. Nothing looks worn and I could not detect any clog or restriction in the carb. I swapped the pumps between the carbs and the carbs performed the same, ruling out the pump. When bench testing the carb I can get it to spray weakly when I actuate the pump quickly but under normal operation I get no stream. I have cleaned the carbs several times but haven't found a good way to clean the channel from the accelerator pump so there could be a restriction within there that I can't detect.

Any helpful suggestions are appreciated.

Options: ReplyQuote
Re: Carb not spraying properly from accelerator pump
Posted by: MattNall ()
Date: June 19, 2021 11:03AM

Accelerator linkage is too long!To adjust you bend it.

Take it off and move the arm manually..you'll see.

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

Options: ReplyQuote
Re: Carb not spraying properly from accelerator pump
Posted by: RobertC ()
Date: June 19, 2021 11:24AM

Did you check that the cup "meets" the wall of the accelerator pump well?

You can use a toothbrush bristle to check the "jets" / "holes" from pump well to venturi.

To clean, you need a real small diameter piece of wire or a small diameter hand twist drill.

Slim possibility that the "jets" are damaged / not fully formed.

Options: ReplyQuote
Re: Carb not spraying properly from accelerator pump
Posted by: Murphy ()
Date: June 19, 2021 12:33PM

Having to go through this recently with a carb. I found the wire trick worked for me. Don't know what was in there, but it's not anymore.

65 Monza Coupe
61 500 Coupe-W100181
Earliest '61 Alive?

Options: ReplyQuote
Re: Carb not spraying properly from accelerator pump
Posted by: 66vairman ()
Date: June 19, 2021 02:47PM

I was wondering the other day if anybody will ever come up with a sleeve to fix the accelerator pump bore. I got a few bases where the bores are pitted or badly worn and the the cup won't seal.

Thoughts -----

Options: ReplyQuote
Re: Carb not spraying properly from accelerator pump
Posted by: Murphy ()
Date: June 19, 2021 04:21PM

66vairman Wrote:
-------------------------------------------------------
> I was wondering the other day if anybody will ever come up with a sleeve to fix the accelerator pump bore. I got a few bases where the bores are pitted or badly worn and the the cup won't seal.
>
> Thoughts -----

Not 'till we run out of good bases. ggg

65 Monza Coupe
61 500 Coupe-W100181
Earliest '61 Alive?

Options: ReplyQuote
Re: Carb not spraying properly from accelerator pump
Posted by: Six Gun Joe ()
Date: June 20, 2021 07:17AM

I did adjust that, originally I got no spray until I got the bend right. Forgot about that.

Options: ReplyQuote
Carb not spraying properly from accelerator pump
Posted by: Six Gun Joe ()
Date: June 19, 2021 11:08AM

I have an automatic '64 Monza with a '62-'63 98HP engine and '64 carbs.

I discovered recently that one carb has a good stream from the accelerator pump but the other does not. Nothing looks worn and I could not detect any clog or restriction in the carb. I swapped the pumps between the carbs and the carbs performed the same, ruling out the pump. When bench testing the carb I can get it to spray weakly when I actuate the pump quickly but under normal operation I get no stream. I have cleaned the carbs several times but haven't found a good way to clean the channel from the accelerator pump so there could be a restriction within there that I can't detect.

Any helpful suggestions are appreciated.

Options: ReplyQuote
Re: Carb not spraying properly from accelerator pump
Posted by: Lane66m ()
Date: June 19, 2021 03:51PM

Get 2 blue viton accelerator pump cups and install them. Your black rubber ones are rotted due to ethanol fuel. Get some top cover gaskets also.

Options: ReplyQuote
Re: Carb not spraying properly from accelerator pump
Posted by: RobertC ()
Date: June 19, 2021 04:58PM

Six Gun Joe Wrote:
-------------------------------------------------------
> but haven't found a good way to clean the channel from the accelerator pump so there could be a restriction within there that I can't detect.
>
> Any helpful suggestions are appreciated.

The answer is in your other thread on the same subject.

Options: ReplyQuote
Re: Carb not spraying properly from accelerator pump
Posted by: Timothy Shortle ()
Date: June 19, 2021 07:48PM

I like to use very thin wire with compressed air to clean the small passages.

Options: ReplyQuote
Re: Carb not spraying properly from accelerator pump
Posted by: Six Gun Joe ()
Date: June 20, 2021 07:20AM

The cups are not rotted but are also not viton, may have been replaced by the p.o.

Options: ReplyQuote
Re: Carb not spraying properly from accelerator pump
Posted by: Six Gun Joe ()
Date: June 20, 2021 07:54AM

RobertC Wrote:
-------------------------------------------------------
> Did you check that the cup "meets" the wall of the accelerator pump well?
>
> You can use a toothbrush bristle to check the "jets" / "holes" from pump well to venturi.
>
> To clean, you need a real small diameter piece of wire or a small diameter hand twist drill.
>
> Slim possibility that the "jets" are damaged / not fully formed.

Not sure if the cup contacts the wall, I can attempt to check that later as well as running a wire through the jets.

Options: ReplyQuote
Re: Carb not spraying properly from accelerator pump
Posted by: Frank DuVal ()
Date: June 20, 2021 09:39AM

there are two small holes for the accelerator pump jets. I use small copper wire to see if they are clear. If not, I have used the small torch tip cleaner wire to remove crap. Do not increase the size of the two holes doing this, though.

The brass check valves are in place? Have you shot carburetor cleaner down through the hole under the brass check valve and see it come out in the pump well? Small copper wire through there might remove some hidden crap in that passage.

If you exchanged pumps and the problem stayed with a carburetor base, there is a slim chance it is still the pump cup and one of the pump wells is slightly larger than the other. With the brass check valve removed, do they equally shoot gasoline straight up?

Frank DuVal

Fredericksburg, VA

Options: ReplyQuote
Re: Carb not spraying properly from accelerator pump
Posted by: RobertC ()
Date: June 20, 2021 11:36AM

Accelerator pump "jets" - 65

Attachments:
Options: ReplyQuote
Re: Carb not spraying properly from accelerator pump
Posted by: MattNall ()
Date: June 20, 2021 11:42AM

0.026"

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

Options: ReplyQuote
Re: Carb not spraying properly from accelerator pump
Posted by: RobertC ()
Date: June 20, 2021 11:49AM

MattNall Wrote:
-------------------------------------------------------
> 0.026"

Bob Helt's book (page 24) states .022"

My feeble memory remembers .023", but maybe that is the size of my Corvair mechanic's hand twist drill?



Edited 1 time(s). Last edit at 06/20/2021 11:57AM by RobertC.

Options: ReplyQuote
Re: Carb not spraying properly from accelerator pump
Posted by: MattNall ()
Date: June 20, 2021 01:16PM

Six Gun Joe Wrote:
-------------------------------------------------------
> I did adjust that, originally, I got no spray until I got the bend right. Forgot about that.
===============================================================

VERY IMPORTANT!! You should've mentioned that in your first post!
------------------------------------------------------

NOW...

1 Do you have two streams from each carb?

2 Is the engine running when you test? or are you keeping the carb bowls full on the bench?

3 Is your float level high enough to allow gasoline to fill the pump well?

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

Options: ReplyQuote
Re: Carb not spraying properly from accelerator pump
Posted by: Lane66m ()
Date: June 20, 2021 03:07PM

Did you try taking the tops off and running the pumps up and down to bore to see if you had a good friction with the wall. Loose cup fit to wall means poor fuel spray into airflow in venturi.

Options: ReplyQuote
Re: Carb not spraying properly from accelerator pump
Posted by: Six Gun Joe ()
Date: September 10, 2021 02:13PM

Sorry for the delay. No luck with old pumps, decided to go ahead and replace the pumps and now it is working. Thanks for all the replies!

Options: ReplyQuote
Pages: 12Next
Current Page: 1 of 2


Sorry, only registered users may post in this forum.
This forum powered by Phorum.