Idle speed - Carb.

[Lumpy Grits]

Hope'n for the best with your birds. It's amazing just how long some of them do live.
Any news on the idle deal yet?
LG

 

[Hedgehog]

Low on money and the Jeep is low on gas so it's sitting until payday and enough time to really warm it up. Other than the idle problem the old girl sure is running well, probably the best it ever has since I got it up and running.

Birds live a long time. Boy ain't that the truth, mine are all around 30 year birds and they are relatively young. They will out live me and I worry some about that. At least non of them are ~75 year birds. In truth most birds, the same as people, don't live that long. Eye sight starts to go and other old age things tend to creep up on them. Most birds die from being stepped on or sat on. Before I had birds it was hard to imagine sitting on your bird. Now that I have a few it's easy to understand. They move around, fly some, walk around on the floor because it's easier to pester the cat that way.

 

[Lumpy Grits]

Any updates?
LG

 

[Hedgehog]

Sorry, I haven't started the Jeep all week, well I did start it, but that was to get my sedan out of the garage and put the Jeep in. Darn it all, I forgot my binoculars in the console, they ain't in there any more. 8x32 Swarovski's it was careless of me, but darn it all. The Jeep was untouched for almost 2 years, can't say that anymore. I might get her out and warmed up this weekend.

 

[Lumpy Grits]

Were they stolen OUT of your Jeep?
Have a Swarovski scope on my .50 BMG rifle. I know how expensive that glass is.
LG

 

[Hedgehog]

Yes, gone from the center console. I don't have a key or it, really that's no excuse, those locks are easy to find. After a long trip the Jeep was unloaded, but I just forgot they were in there. In a way I was lucky, they were used and I didn't pay nearly what they were worth, but still .... Errrrrrrrr.

 

[Lumpy Grits]

Real sorry to hear this!
I spent the best part of my life put'n those kinds of lo-life's behind bars.
Check out the local garage sales and pawn-shops.
Sounds like kids--
LG

 

[TeamRush]

Ok, the engine is a swap into a '75 CJ...

What carb? Which Choke, electric, manifold heat or manual?

This is a shot in the dark, but happens and a carb guy (instead of emissions guy) would have checked for it since it's common...

The CHOKE PULL OFF, (not the choke blades) wears over time and doesn't have the spring pressure to pull the choke/high idle completely off.

Remember, the choke is FULLY ENGAGED at rest, and the amount of engagement can be adjusted for your 'Average' cold start condition by turning the CHOKE PULL OFF canister.

Since it's ENGAGED at rest (Cold engine), it's activated every time you start the engine.
If the Choke PULL OFF can't get the choke fully open, and the high idle fully pulled off, then you have rich fuel mix and high idle issues even after the engine warms up...

This will allow the high idle to keep the CURB IDLE screw off it's seat and produce High Idle speed when you don't want it.

This is a particular problem with Carter BBD carbs with high idle independent of choke/choke pull off canister.

When the choke is set on a carb,
The CHOKE PULL OFF allows the CHOKE LINKAGE to close the CHOKE BLADES,
But the CHOKE PULL OFF also sets the HIGH IDLE cam under it's adjustment stop arm.
Sometimes this is a bent piece sticking out of linkage,
Sometimes it's a screw adjustment for the high idle.
But every carb with a choke has a high idle cam and limiting stop that contacts that cam on the linkage.

If the choke PULL OFF isn't strong enough to return the linkage to 'Normal' or 'Warm Run' position, you will have high idle,
And your CURB IDLE speed adjustment will not work to lower the idle speed when warm.

Between wear/slop in that high idle linkage, and a weak Choke Pull Off spring in the canister, this is a pretty common complaint, and often winds up as a diagnosis of 'Shaft Wear' or 'Internal Vacuum Leak' or some other silly excuse for not adjusting the linkage or changing the Choke Pull Off canister...

With MC 2100 carbs that had manifold heat pulling off the choke can, a break in the line will NOT deliver the required hot air to the choke pull off to get the choke pull off to FULLY DISENGAGE the high idle.
And again, the bi-metal spring in the choke pull off will weaken and stretch over time/heat cycles, and not fully pull the high idle cam out of the throttle linkage...

Carter BBD carbs have a particular quirk,
The CHOKE PULL OFF sets the high idle/choke blades,
but it will NOT pull the high idle off as it warms up.
The high idle will hold the choke CLOSED until you 'Blip' the throttle to release the high idle cam 'Teeth' from the high idle adjustment screw.

 

[Hedgehog]

Now that's an answer.

I thought I'd mentioned it but I have the stock Motorcraft 2150 on the Wagoneer 1982 AMC 360. I had it rebuilt and it was bench tested, what ever that means. When they rebuilt the carb. many new parts were added, choke and altitude adjuster (?). The manifold heat tube to the choke is installed and is rust free. I have always felt that something in amongst all the interconnecting linkages was sticking. I felt this way because fiddling with the linkages will settle the idle speed down nicely.

 

[Lumpy Grits]

Have you thought about either a heavier or an additional throttle return spring?
BTW-Listen to what TR has to say-
LG

 

[Hedgehog]

Lump - Lumpy - Lumpy of course I'm going to listen to TR. The carb rebuilder says that overly heavy return springs create excessive wear on the carb shafts. I've already got a couple springs on the return, more to give the gas pedal feel than for return.

 

[Lumpy Grits]

Hog - Hog - Hog, Ol'boy
If you disco the linkage where the throttle cable attaches. Does the carb linkage move freely or still bind some??
What about after you disco the choke linkage???
LG

 

[Hedgehog]

I believe it's free, will have to check it out.

 

[Lumpy Grits]

Good luck in find'n the issue.

LG

 

[donald naslund]

I would start by disconnecting the linkage at the carb to make sure that the linkage isn't binding somewhere. leave the return spring on the carb. check the fast idle cam at the choke when the engine is warmed up. the screw should not be on the cam. if it is off of the cam, check the idle screw. if it is not touching the stop then there is a problem with the carb.

 

[Lumpy Grits]

Any updates
LG

 

[Hedgehog]

In another thread I wrote about having my bikini top pop it's straps while zipping along on I-10 at +70mph. I really don't drive at +70mph very often, I was giving her a good workout while working with the carb.

After fiddling with it as suggested, nothing has changed. The carb needs to be pulled for another close inspection.

 

[DHugg]

I would start by disconnecting the linkage at the carb to make sure that the linkage isn't binding somewhere. leave the return spring on the carb. check the fast idle cam at the choke when the engine is warmed up. the screw should not be on the cam. if it is off of the cam, check the idle screw. if it is not touching the stop then there is a problem with the carb.

The hi-idle choke cam jams frequently on my MC2100 Reman. I'm going to switch over to manual choke. Too much automation is not helping me any.

 

[Hedgehog]

After much fiddling and pondering on the idle problem it occurred to me that problems started but less so back when the charcoal canister purge vacuum line was installed on the vacuum nipple on the PVC valve as it would have been in a Wagoneer. Today I pulled the line, capped it and installed the purge line on the air filter housing as it was in '75. Surprise, surprise, surprise, the idle speed dropped right down to where it belongs and seems to be consistent.

So, in the end most of you were mostly right. The PVC nipple arrangement created a vacuum leak. Most likely the newer canisters handle purging differently.

 

[Torxhead]

For what its worth on my oem canister, the purge valve does have a constant vacuum leak to the inside. This allows gas fumes from the tank to go down the carb. On a replacement canister that I have made by Standard there is no vacuum leak.