Carb Linkage

Date: Fri, 13 Jun 1997 09:03:14 -0700
To: barney@flowpoint.com
From: Barney McNamara 
Subject: Carb Linkage

I also have a question about my truck, back in April (from my saved 
threads) I saw a suggestion from you about a problem a guy was having 
with an '87. He said his engine would not idle down to the setting of 
the adjustment. Mine is a carburated '83, and I have the same problem. 
Once it warms up, it acts like the accelerator is sticking. When it is 
cold, it idles nice and slow, of course the choke setting doesn't match 
the marks on the cover, I drilled out the rivets and reset it way over 
long ago. I set it back out of the way, as I don't need it here in 
California, and I thought it could somehow be the cause of my problem. 
It does heat up, as the blisters on my wrist prove from the last time 
I messed with the carb. 

When I let off the gas pedal, it releases, but sticks at about 1200-1800 
RPM.  I can get it down to the setting of ~800 RPM by pushing down on the 
end of the linkage. You suggested to the other guy that it could be his 
bell crank or throttle cable. I assume you were discussing a truck with 
EFI, but I took that hint, and took out my linkage and greased it up. 
It is very worn, the hole where the arm rotates is much larger than the 
shaft, so there is a lot of slop. After greasing it, the idle did improve 
(it had been 2000 RPM). I also bought a replacement linkage at the junk 
yard for $10. It is less worn than mine, the plastic washer is still 
there. But it acts just the same on the truck - 1400 RPM. I went to two 
local dealers to look at a new one - I've never seen any except mine. 
They didn't have one in stock, but offered to order one for $150. I 
turned it down. I finally bought the Toyota manual for my truck ($70 
from Downey) but it says not a word about the linkage. Since the swap 
of the second linkage made no difference, I'm assuming that it is not 
the problem. 

This all started on my last trip to Hollister, after splashing through 
the mud so much my alternator clogged up. The brake and charge idiot 
lights were on, but went off after I washed it out, luckily. I opened 
the air cleaner and found a ton of sand in it from Death Valley. I 
think that the bouncing at hollister knocked some sand somewhere into 
the carburetor, and that is screwing up something that is causing the 
carb to go into fast idle mode when warm, instead of cold. I can't 
really see in there when it is warm, and when I took the carb out, it
all looked OK on the bench. My gas mileage is also down for ~18MPG 
to ~15MPG.

Any way, thanks for reading this far, my next plan is to get another
rebuild kit for the carb (I rebuilt it once when I got the truck - it
came with a can of carb cleaner to start it with because the 
accelerator pump was full of dirt and wouldn't squirt any gas in to 
start it up.) And newly armed with the factory manual, charge back 
into the carb and try again. 

Any other thoughts?

Thanks - Barney


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Date: Thu, 12 Jun 1997 23:00:16 -0700
From: James Brink 
Reply-To: brinkjm@earthlink.net
To: Barney McNamara 
Subject: Re: Get together this summer?

Barney,

Wow! $150 for a linkage bellcrank??? The last one I bought was about
$45.00. Do you want me to double-check this for you? If you compare the
side-to-side play of the old linkage to the new one, you'll see the
difference it can make. Is your throttle cable worn or frayed? This can
cause the linkage to hang as well. I'll betcha' it is the bellcrank. 

I doubt the sand would affect the idle speed from inside the carb. The
linkage is on the outside and the throttle plates are right there on
top. Sometimes the choke linkage gets gummed-up however. Try cleaning it
thouroughly inside and out with carb. spray before the overhaul to see
if it makes a difference.

Let me know if I should persure the bellcrank. I can probably get you a
good price if you want.

Take care,

Jim

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Date: Fri, 13 Jun 1997 09:03:38 -0700
To: barney@flowpoint.com
From: Barney McNamara 
Subject: More on carb linkage

Jim,
Thanks for the offer, I actually got two quotes - $30 at the Santa Cruz
Toyota dealer, and $150 at Stevens Creek Toyota. I assumed that the
Santa Cruz guys were wrong, but it sounds like it was the others who
checked the wrong part number.

I tried reworking one of my old ones again, and it is real smooth and
nice now. I found a nylon bushing, cylinder shaped with the right ID for
the original plastic shoulder washers on the shaft, and the right OD to
fill the oversize hole on the carb side of the mounting bracket. The
length is perfect, too, and goes through the oversize hole, and butts
against the other side to stay in place. This caused the play to go away,
but the alignment wasn't quite right. So I drilled out the mounting holes
oversize, to allow it to align to minimize resistance to the rotation.
I set it in there, then allowed just the spring on the carb linkage to
align the bell crank. Then tightened it down. It moves real smoothly now
and doesn't bind. But .... the idle still sticks, and I can force it
down by rotating the linkage :-(    This is probably a lot more detail
than you wanted to know, but this thing is stuck in my mind, and I'm
trying to work it out.

I'll take off the carb again, and try looking closer at the linkages
there. It runs so well otherwise, I am reluctant to mess with the
guts of the carb. 

The exposed ends of the cable look fine, is it possible that it could
be frayed inside the housing, causing it to stick? The cable is old
and stretched, and even when the idle is high, the cable seems loose.
That's why I haven't done anything else to it, yet.

It looks like I will take the truck to Pismo tomorrow :-) My buddy
and his wife decided to go with us at the last moment. Too bad, I
can't go slow, but maybe I can fix it first thing in the morning.

Thanks for the help - I'll keep you informed.

Barney


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