Vacuum Carb Help

[Bo Rogers]

Hi all,

I just picked up a new to me buggy that I am having trouble starting. A little background. I asked this question in the general discussion forum so for those guys that gave a insight there thanks. I decided to move the question to here.

After some questions and answers I learned that I have a vacuum pepcock and carb. I found where they are to be connected, from the pepcock to a T to the carb and to the intake manifold.

But my issue is I still cant get it to start. I pulled the carb apart and cleaned the needle jets both the idle and main. I reconnected everything and cranked it, no fire unless i gave it starting fuel. I would fire and run until it ran out.

I realized that no gas was getting into the bowl. I removed the float and clean out that needle valve it was completely plugged and would not allow any gas to enter the bowl.

Since I was at it I went ahead and removed the vacuum pepcock and made a manual one. See the attached pic.

Well, it still does not start and now gas pours out from the bottom of the carb. Clearly I have goofed up somewhere.

Also, I connected the vaccum from the intake directly to the carb. Was that correct? You will also note that there is gas in the vaccum hose.

Of the 4 or 5 pictures I added is one of the top cover off the carb. I could not find any cracks or dry rot in that diaphragm. Does it look ok?

I could you some help so please take a look, I really appreciate the help.

Thx Bo

[ckau]

The manual shut off looks good! The vacuum line is routed correct. It should run directly from the intact nipple to the slide diaphragm on top of the carb. Now that the carb is gravity feed, the float and needle valve has got to be working properly. You have probably , by accident, altered the float setting while cleaning. This causes fuel to constantly flow. As the fuel level rises in the bowl the float rises also to force the needle in the seat to close off the flow. The needle has a neoprene tip that is very fragile. Inspect it closely to insure there is no damage, signs of compression, any dents or nicks. inspect the seat closely for trash or deposits around the opening. Good chance while changing tank valve and lines ,some trash go down into the carb. Invert the carb, remove the bowl and hold up to eye level. check to see the float pivots freely with no hang ups. DO NOT push down on the float! The needle has to rest naturally in the seat! Pushing will dent the tip and alter the float position. Insure the float rests level with the bowl mounting edge of the carb. Adjust with some needle nose pliers, being careful to not put pressure on the needle tip. the needle is attached to the float with a small wire clip . this clip is hung on a tab. This tab is bent to get correct float position. There are pictured tutorials on the web detailing this procedure.
sometimes it is more advantages to simply replace the carb. They are cheap and plentiful on e-bay. Make sure you save the main and pilot jets from the old carb to install in the replacement if you go this route.
Normaly when the float and needle stick there is raw fuel dumped into the cylinder. check the oil for fuel contaimination. Change the oil and replace the plug.

[Bo Rogers]

Originally Posted by ckau

The manual shut off looks good! The vacuum line is routed correct. It should run directly from the intact nipple to the slide diaphragm on top of the carb. Now that the carb is gravity feed, the float and needle valve has got to be working properly. You have probably , by accident, altered the float setting while cleaning. This causes fuel to constantly flow. As the fuel level rises in the bowl the float rises also to force the needle in the seat to close off the flow. The needle has a neoprene tip that is very fragile. Inspect it closely to insure there is no damage, signs of compression, any dents or nicks. inspect the seat closely for trash or deposits around the opening. Good chance while changing tank valve and lines ,some trash go down into the carb. Invert the carb, remove the bowl and hold up to eye level. check to see the float pivots freely with no hang ups. DO NOT push down on the float! The needle has to rest naturally in the seat! Pushing will dent the tip and alter the float position. Insure the float rests level with the bowl mounting edge of the carb. Adjust with some needle nose pliers, being careful to not put pressure on the needle tip. the needle is attached to the float with a small wire clip . this clip is hung on a tab. This tab is bent to get correct float position. There are pictured tutorials on the web detailing this procedure.
sometimes it is more advantages to simply replace the carb. They are cheap and plentiful on e-bay. Make sure you save the main and pilot jets from the old carb to install in the replacement if you go this route.
Normaly when the float and needle stick there is raw fuel dumped into the cylinder. check the oil for fuel contaimination. Change the oil and replace the plug.

I went back this morning and worked some more on the carb. It still pisses gas out but at least i got it running around the block. It ran great but no matter how much I jag with the float I cannot seem to get the float correct. I turned the carb upside down and blew through the gas intake and no air moved through the float. When inverted correctly air moved through but of course when reassembled no luck. I will keep at it. Thx for the advice. Bo

[kobraman]

I was told by a mechanic that once you go manual with your petcock, ( meaning you dont use the vacume lines to the petcock) That you just plug off your Vacume ports on carburetor and intake. Heres the deal now though. Your petcock has the safety feature that when the engine is not running you wont have fuel flow. So now that you have a manual one, it might be a good idea to shut your fuel off every time your not useing your buggy.

[SLESTAK75]

There is a drain at the bottom of the carb. If the fuel is coming out the bottom then the drain is open. There is a screw next to the drain nipple. Make sure this is screwed all the way in. If there is no screw then it was removed and not replaced by previous owner and needs to be replaced.

[SLESTAK75]

Originally Posted by kobraman

I was told by a mechanic that once you go manual with your petcock, ( meaning you dont use the vacume lines to the petcock) That you just plug off your Vacume ports on carburetor and intake. Heres the deal now though. Your petcock has the safety feature that when the engine is not running you wont have fuel flow. So now that you have a manual one, it might be a good idea to shut your fuel off every time your not useing your buggy.

With no vacuum petcock you run the intake vacuum straight to the nipple on the "passenger" side of the carb

[Breakhard]

Bo, I was where you are about a month ago. Finally broke down and purchased a new petcock with the vacuum. Put it on, hooked up the "new" vacuum lines and presto, no more problems. New petcock on eBay was less than $10 including shipping.