problem with automatic chokes?..maybe not update 5/17

[thenexttownshend]

I think i may have a problem with the automatic chokes on my carbs. 1973 with correct carbs ( i belive ...maybe '74 engine) Ive been having a difficult starting it up, Its sat for two years, but ive checked compression, installed new plugs, replaced old oil/gas. Once it warms up it idled fine, enough so i took it for a test drive up and down the street. (I assumed it ran rough at first being the first time in two years) But the next day It starts momentarilly then stalls unless im quick with the gas pedal. Then still its difficult to keep going.

Ive noticed the connecctions were poor looking coming from the coil to the chokes, so i remade them and found the left choke male spade plug was loose, i removed it thinkng it may be broken inside, but the heating element looked ok i reset the choke, the bentley isnt to clear on how to do so, (at all) So i turned the choke that the bimetal sping catches on, realized there was a second arm behind that, that when turned cought the choke and held it open. Then i replaced the heating element cover, turned it until it cought the first arm and pushed it all the way clock wise and reassembled, from there. Does that make sense? Should this left carb choke be loose, heating up significantly more then the right one? Am i even in the ball park?

[type2sam]

Steve,

Colin will likely swoop in here...but perhaps I can give you some ideas until then.

You definitely want to make sure that both choke elements are heating up and expanding the bi-metal springs in the presence of 12V. It sounds like you have determined this through observing that the element is not broken, however it never hurts to actually look at the element with 12V connected.

In terms of adjusting the chokes, you want to make sure that the hook on the bi-metal spring is catching the black arm with the white plastic sleeve on it (one of my carbs has the sleeve - yours may not - but it is certainly a black arm) and rotate it until the little mark on the edge of the automatic choke coil body (hold the choke between your fingers so that the SOLEX is horizontal - move from the X to the edge of choke, then counterclockwise along the edge about 5/8") is between the 2 marks on the carb body where the choke mates to the body. On the right carb I am holding in my hand, these marks are between 12 and 1 o'clock with the carb held in the normal in-car orientation. Position on the left carb is similar IIRC. This should get you in the ballpark.

I set mine mid-way between these marks and find that my chokes kick in even if I have quickly stopped for coffee. I need to adjust them.

You also want to make sure that your 3 electomagnetic cutoff valves are working - applying 12V and hearing them click is a way of testing.

[satchmo]

On a cold morning, go out to your poor engine and remove his carbs intake hats (the 'pizza slices'). The choke plates should be full closed. If not, blip the throttle shaft a little, enough to get the choke off the cam steps inside the choke housing. Now both chokes should be full closed. It they still aren't closed, loosen the locking ring that holds the choke cover a bit and rotate the cover enough to close the choke. (if turning the choke cover one way opens the choke, well then, rotate the other way).

Now you have both chokes fully closed. Turn the ignition to the ON position (not to start - you just want 12v going to the chokes rather than the engine running). Also open both throttle plates completely by just rotating the accelerator cable cross shaft until it stops. Now the chokes are off the step cams and are free to open smoothly and completely as the wire spring inside the choke heats up. Observe that both chokes should be synchronous in this opening dance. If not, investigate. You may have to open up the choke housing and check the function of the spring and that the spring actually catches the post for the shaft of the choke butterfly.

Clear as mud, ey? Tim

[thenexttownshend]

Ok thanks satchmo, that was a pretty good way to test, unfortunately (fortunately!) my chokes seem to be in pretty good shape the open slowly togeather, once they are almost open a quick tap of the gas and bang fully open. electromagnetic vaves click nicely when i pull the plug on/off

But still ive got a difficult start/idle problem.

It starts up pretty good the first time a turn or two and it goes, revs up high then any attempts to give it more gas and it bogs down, (wee woosh sound) and eventually stalls. I did mess with the timing, moving the distributer back and fourth a bit the first day when it was running great, and i was satisfied when i was done. I adjusted the idle screw on top of the left carb a bit but that dosnt seem to help at all it was about 2 1/2 turns up orignally and i put it back to that.

Ill go over it again, make sure i have no vacuum leaks again tomarrow, any other suggestions? Am i trying to hard to bring back carbs that sat for 2 years without a rebuild? If that were the case wouldnt it have ran like this the first day i started it back up?

[type2sam]

So, first off..were these rebuilt 2 years ago? Or were they working as is 2 years ago?

Next, have you gone through this adjustment procedure?

viewtopic.php?t=7767

I pieced together a set of duals and rebuilt them by following Richard Atwell's DIY --> http://www.ratwell.com/technical/DualCarbs.html

I attempted Colin's procedure above on my own, but kept failing to get past 2B.

Colin was out in 2008 and walked me through it. Now they run (and idle) incredibly well.

[satchmo]

If it sat for a while, I'd be worried about old gas/varnish and other junk in the carb passageways. At the least, I would take the carbs off for some inner cleaning if not a rebuild. The main jet is accessed through a hole in the bottom/back of the float bowl. A long shaft flat blade screw driver can retrieve it for cleaning. Also remove the cut-off solenoids and spray the holes they came out of with gum-out or something. And spray out all the needle valves (one in each throttle plate, plus the idle speed valve).

When we restarted glasseye's 74 bus, it had plugs of varnish (old gas) in the carb passageways. It never would have run without cleaning.

Tim

[Amskeptic]

Ok thanks satchmo, that was a pretty good way to test, unfortunately (fortunately!) my chokes seem to be in pretty good shape the open slowly togeather, once they are almost open a quick tap of the gas and bang fully open. electromagnetic vaves click nicely when i pull the plug on/off

But still ive got a difficult start/idle problem.

It starts up pretty good the first time a turn or two and it goes, revs up high then any attempts to give it more gas and it bogs down, (wee woosh sound) and eventually stalls. I did mess with the timing, moving the distributer back and fourth a bit the first day when it was running great, and i was satisfied when i was done. I adjusted the idle screw on top of the left carb a bit but that dosnt seem to help at all it was about 2 1/2 turns up orignally and i put it back to that.

Ill go over it again, make sure i have no vacuum leaks again tomarrow, any other suggestions? Am i trying to hard to bring back carbs that sat for 2 years without a rebuild? If that were the case wouldnt it have ran like this the first day i started it back up?

If it starts off the chokes well, but gets crabby after a couple of minutes, you likely have crap in the cut-offs, varnish like satchmo said. I put a pox on your engine because you have my small visegrips.
Colin

[Gypsie]

[ I put a pox on your engine because you have my small visegrips.
Colin

Yowch....