Coming from High Altitude to Alabama - Adjustments? (1 Viewer)

[Dlathem]

When I picked up my 60 in Colorado last week, I didn't notice it idling high. Now that I'm home in Alabama, it's idling between 1500 and and 1700 RPMs.

Should I check the timing first, THEN dig into the carb adjustments? I don't notice any pinging and it runs fine, it just idles too high. I tried tweaking the idle adjustment screw Saturday, but the truck was hot as hades and the engine fan blowing hot air on me didn't help so I gave up after a few min but couldn't make it change at all. I have the FSM and know I'm turning the right screw. Factory carb, btw.

I'm just not sure what's typically tweaked to compensate for elevation or if the HAC thingie handles that for you.

Thanks!

 

[unklwedy]

HAC should automaticly adjust for altitude, But it's 30 years old... Try plugging the 2 outside vacuum tubes on airhorn. Check ignition timming. Possibly blockoff secondary advance diagphram.

 

[flintknapper]

When I picked up my 60 in Colorado last week, I didn't notice it idling high. Now that I'm home in Alabama, it's idling between 1500 and and 1700 RPMs.

^^^^^ Probably just nervousness (vehicle moving from Colorado to Bama).

Once it realizes it didn't go to LA (Lower Alambama) it will most likely settle down.

 

[morganism]

PO prob had it advanced to 15 or 20 on timing for HA. Re-time down to 7-10, and do the lean drop on the carb then. (even better, use a vac gauge to time it)

Also check the threads on the carb cooling fan, to lessen vapor lock symptoms.

look down hood intake vents for interior air too, if you see lots of pine needles, you need to clean in there for drains, and drop blower motor and clean out the mounting in there.

 

[Dlathem]

Thanks for the help. I’ll start with the timing then. Carb fan seems to work fine, runs every time I stop for 10min or so.

 

[Dlathem]

Ok, I must be missing something. I cannot make it idle down.

1) I have a Pertronix ignition.
2) Checked the idle screw (not the fast idle) and it isn't even touching the linkage. I cannot make it idle any lower.
3) I managed to pull back on the linkage enough to get it around 1k RPMs.
4) Set timing, right on the BB.
5) Released linkage, back up to 1500 again.

No matter how I adjust the mixture screw, I can only make it idle up. Right now I'm only about 1 turn out. Once again, the idle speed screw is so far out that it's not even touching the linkage. What am I missing?

I don't know if it's relevant, but the PO did the "white wire ground" thing and told me that it wouldn't idle so he grounded that wire. I hooked it back up and it made zero difference. It runs the same for me whether the wire is grounded or connected.

I can make it idle down by turning down the timing butit should be on the BB.

HELP!!

 

[mattressking]

Disconnect choke cable and throttle linkage. If it is still idling high, make sure the butterfly is completely closed and choke butterfly all the way open.

Report back once we know that stuff is working correctly.

 

[Dlathem]

Ok, got it straight. Thanks for the linkage idea. The "plate" was loose on the driver's side and I tightened it. I had my head so far up the FSM's ass that I didn't notice that my carb ALSO has an idle adjustment on the FRONT of the carb. Fuel mix is where it should be. Fast idle is where it should be, idle is toward the driver's side fender from fast idle. C-H-E-C-K!! I never took 1/5 seconds to notice that there is also a screw on the front of the carb that adjusts the idle. Tweaked it and the mix today, reset the idle, and it's running like a sewing machine. Thanks again.