carb trouble

[squatches]

the second barrel on my carburetor will not open when throttle is all the way open, if you push the accelerator pump it goes on but when under normal conditions it stays stuck closed until u bump it with your hand. any ideas as to the problem and how to fix it? this is on a stock l16 hitachi 2bbl carb.

 

thanks

[datsunaholic]

The secondary is vacuum operated. It won't open unless the engine is running, generally with pretty good RPMs and some load. Now, if it's sticky you probably just need to clean the linkages and make sure there isn't a gasket protruding into the throttle bores.

[banzai510(hainz)]

rev it up high then put your hand over the main barrel and the 2nd should try it open up for a second or so b4 it wants to die out.. if not then its stuck.

[datzenmike]

the second barrel on my carburetor will not open when throttle is all the way open, if you push the accelerator pump it goes on but when under normal conditions it stays stuck closed until u bump it with your hand. any ideas as to the problem and how to fix it? this is on a stock l16 hitachi 2bbl carb.

 

thanks

 

You must mean the vacuum diaphragm at the rear left.

[squatches]

yes the vacuum diaphram sorry about that, so when the throttle linkage twist's it's not supposed to open that? or is it all vacuum operated?

[datsunaholic]

It's entirely vacuum operated, but it does have connecting linkage to prevent it opening when the primary is closed.

[squatches]

ok so i took the carb off and cleaned the second bore out and made sure it moved fine and still same problem its like its not opening at all and this is on a rebuilt carb. it ran fine for a long time and has just now started acting up.+

[banzai510(hainz)]

dude

Did you do the hand trick as I mentioned???????

Do it

rev the fucker up then put your hand on the main barrel. this should cuase the 2nd barrel to open. if it dont open then thats our proplem.

 

 

 

when you put carb back together hopefully you put the aircleraner back on as it helps crerate a vaccum by added resisitance

 

after that if still bad

Buy a weber.

[squatches]

dude

Did you do the hand trick as I mentioned???????

Do it

rev the fucker up then put your hand on the main barrel. this should cuase the 2nd barrel to open. if it dont open then thats our proplem.

 

 

 

when you put carb back together hopefully you put the aircleraner back on as it helps crerate a vaccum by added resisitance

 

after that if still bad

Buy a weber.

 

 

 

yeah still doesnt open, will be getting a set of su's or sidedrafts this monday or tuesday.

[mike]

Check the connecting linkage on the back and see if its rubbing/catching on the carb body. Over time the holes in the linkage wallow out a bit from normal operation allowing the linkage rods to have a little extra play in the wrong direction.

 

Ive had this happen before and I fixed it by adding one or two of those little washers to space the linkage rod away from the carb body. You can also bend the linkage a little outwards if its still catching... It doesnt take much at all. It will also take out some of the slack from the worn parts. Using two pairs of vice grips makes it easy.

 

Does it rev up fast and smooth from idle to when the secondary should open or does it take a bit to spin up? Have you checked for vacuum leaks around the base and your intake manifold gasket? That vacuum diaphragm or the hose going to it may be bad...