Rebuilt carbs - idle is hunting

[Jerbearyukon]

So I had my carbs rebuilt at Dennis's......I get them back and bolt them on.....I fired it up and they wouldn't idle....

Dennis is stumped (and that is VERY hard to do). THey ran great on a Pinz in Denver at 6000 feet.....

I HAVE REPLACED MY MUFFLER OK (don't know if that has anything to do with all this).

So I thought I would throw this out to the gang incase somebody has come across this too.

1 - We tried ( friend of mine gave me a hand) to set the timing and carbs.....these carbs were set for 6000 feet and we are at 2400.

Couldn't get it right...move the distributor and get it where it was in the 850-900 range and then 3 seconds later it would shoot up to 1200-1300.

Man you just move that thing a hair and it just jumps....

WE couldn't set the timing cause the revs kept changing.

I have replaced all the fuel hoses and clamps.

So then we tried to set it lower and adjust the screws in the carbs (set 3/4 turn out from bottom by Dennis.

So we did that and adjusted them out 1 full turn - would idle and would hunt before quitting....out another 1/4 turn.....idle up to 1200....hunting up to 1400....turned them back and 1/8 turn and it was 750-1000 - 1100 but still hunting. It wants to stay at the low revs and then just speeds up and comes back down again.....WIERD.

ANYONE at the same elevation as I am and know what they have their screws set at?

Anyone know what is causing the hunting.

Dennis had us pull the distributor and check the spring and weights under the points and it seems fine....fuel pump is pumping fuel.

Funny thing (if you can call it that) we got it to idle (rough but it was idling) at 700 - 1050 (hunting) with the air breather off.

Then I just got frustrated and put everything back on and then it wouldn't idle at all....The air filter is BRAND NEW.

He told me to pulll the jets out and hit it with some air to make sure there isn't anything that got jammed in there during shipping.

I TOOK SOME VIDEO:

Beginning - put carbs on - pulled linkage from front carb - check solenoids to make sure they all clicked.

http://s248.photobucket.com/albums/gg16 ... I_8086.mp4

screws turned out 1/2 turn cause is wouldn't idle:

http://s248.photobucket.com/albums/gg16 ... I_8089.mp4

another 1/4 turn

http://s248.photobucket.com/albums/gg16 ... I_8090.mp4

Linkages back on:

http://s248.photobucket.com/albums/gg16 ... I_8091.mp4

Everything back on - outside running - notice the high idle at the end - this is what it is doing....

http://s248.photobucket.com/albums/gg16 ... I_8093.mp4

am all ears....Jer

[4x4Pinz]

have you sprayed around the shaft ends and base gaskets with something like wd40 to verify there is no leaks at new base gaskets you installed with the carbs? Pull the tin and make sure intake manifold gaskets are tight and that the manifolds themselves are not broken. Why did you get the carbs rebuilt in the first place? Seems to me people play with the carbs way more than they need to. What I seem to see is in most cases the rough idle/running is not a carb issue but rather something around the carbs.

[Jerbearyukon]

Well it has never really run very good and got to where it was backfiring and actually blew the back of the muffler out.....when I sent them to Dennis one of the solenoids was hooped ( that was probably causing the backfiring dunno) which I didn't know and it was really GUMMED up - took 6 days of soaking to get them clean.

I will give it a go...thanks

Jer

[Jerbearyukon]

So what will the WD40 do - bubble?

Jer

[Jerbearyukon]

So what will the WD40 do - bubble.....had to resend this because my browser got hung up...hopefully it's not a double post

Jer

[4x4Pinz]

if the engine changes rpms then you know you have a leak at a gasket or oring. Some use carb cleaner that it not combustible to find leaks. Just a lazy mans way of finding them without taking everything apart. Of course it must be running at the time.

[Jimm391730]

Your lack of consistency does sound like a vacuum leak. One place to check is that the intake manifolds are not cracked or leaking at the cylinders; you must take the engine tin off to check. Spray down where they meet the cylinders and listen for any change to the revs. Depending on what you use, the revs could increase if the spray is flamable or decrease if it just blocks the airflow through a crack or gap. But any change in rpms is a sign of a vacuum leak. Also check the hose between the two manifolds and the brake vacuum booster hose for cracks or other damage.