Holley 19XX Series Carb Stuff

The nylon accel pump arm and linkage are broken off and long gone on a 1904 I'm dealing with. Obviously creating a minor driveability problem...

Does the ihon rebuild kit contain these parts or will I need to source them independently?

Thanks
 
hooptytank said:
the nylon accel pump arm and linkage are broken off and long gone on a 1904 I'm dealing with. Obviously creating a minor driveability problem...

Does the ihon rebuild kit contain these parts or will I need to source them independently?

Thanks
Click to expand...

Carburetor rebuild kits do not contain the actuator lever or link for the accelerator pump.

On top of that, we must know which variation of the 1904 you actually have, so post a picture and I can tell ya. I must be able to actually see the accel pump actuator and pivot point on the side of the carburetor in order to make a correct determination.

I do have some levers available, some are the oem nylon, others are a steel product. But the two types do not interchange on the carburetor.

Post a pic and let me see what you have.
 
eightosix said:
I am finally back on this project. Drove the Scout quite a bit this summer, and it runs pretty well, although I can notice a hesitation when I throttle it. I had sent in my main well to michael for a poppet rebuild.
Attached are a couple photos showing the new arm I bent up from 1/8" rod and the initial setting for the float - slightly up from level. The new arm is about .94" inside dimension and causes the plunger to start moving with any throttle movement. The throttle will open all the way to the stop.
I installed a #57 jet, and left the tiny spring bumper on the seat assembly. The mm "rough trail" mods will be utilized.
I plan to switch out the carbs within a few days. The new setup will delete the oil bath filter with a paper filter.
Click to expand...

Installed the rebuilt carb on the 152. The kit did not include the proper base gasket (probably for a 196?) so I reused the old one, which was in good shape.
All was good until fuel started coming out the vent. Took some time - like 4-5 minutes at idle. So I pulled the cover and adjusted the float - still passing fuel. Adjusted again, no good, so pulled the carb to try and figure what I did wrong. What I determined was that the needle and seat was out of the carb it held pressure, but when it was installed in the carb there was a slow leak both with pressure and vacuum.
Somehow it was leaking around the (new) copper washers on the fuel inlet seat screw. I checked them for burrs and the seating surfaces also.
After several assembly attempts finally they seated. Reinstalled the carb and adjusted the idle and air. Took it for a spin and no apparent fuel shortage from the 57 jet.
 
My Scout's been sitting for a while and as of last night it really doesn't want to idle. I need to choke it out to about 1000 rpm or so to keep it alive. It drives and accelerates okay, it just doesn't want to idle without being opened up a bit. Any suggestions? My first thought is maybe the gas has just gone bad. It's probably about 5 month old gas and it's been sitting in a 100+ degree garage here. I almost threw away a chainsaw that was driving me insane and that turned out to be an old gas problem.

It was running okay last time I fired it up, maybe 6-8 weeks ago.
 
mastiff said:
my Scout's been sitting for a while and as of last night it really doesn't want to idle. I need to choke it out to about 1000 rpm or so to keep it alive. It drives and accelerates okay, it just doesn't want to idle without being opened up a bit. Any suggestions? My first thought is maybe the gas has just gone bad. It's probably about 5 month old gas and it's been sitting in a 100+ degree garage here. I almost threw away a chainsaw that was driving me insane and that turned out to be an old gas problem.

It was running okay last time I fired it up, maybe 6-8 weeks ago.
Click to expand...

When you activate the choke, you're closing off air supply which reduces the air to fuel ratio, which is usually a necessity on a cold engine. If you're having to do this on a warmed up engine, it indicates the idle circuit is not meeting the consumption demand or there could be a vacuum leak. E10 gas does begin losing volatility almost immediately. Its a good idea to treat your fuel supply with marine stabyl which is the bluish-black formula, not the red stuff, especially if the vehicle sits inactive for months at a time. Before you do anything, you could try temporarily running off a small can of fresh gas to see if that alone returns things to normal.
 
Which one is the air screw?

My feeling is that the reason the choke is keeping it alive is simply because it is also keeping the throttle open, but I haven't proven this. I did treat the gas with the dark color stabil.

There's not much there to leak vacuum wise. Maybe the carb base gasket? I'll spray some carb cleaner around and see if I can find something like that. Thanks.
 
You're correct. As the throttle plate opens, the carb transitions from idle to cruise. At 1k rpms, the idle circuit is still active. 6 mo treated fuel should be okay. If you have vacuum wipers sourced from the fuel pump, that's another potential leak source.
 
There are only two screws for adjustment on a 1904. The idle scew is on the left side, right where the throttle cable attaches to the throttle plate.
The air screw, maybe called the idle air screw, is also on the left side, at he rear base of the carb.
I could send a picture, but if you look back in this thread, there is probably a good photo already here.
 
eightosix said:
there are only two screws for adjustment on a 1904. The idle scew is on the left side, right where the throttle cable attaches to the throttle plate.
The air screw, maybe called the idle air screw, is also on the left side, at he rear base of the carb.
I could send a picture, but if you look back in this thread, there is probably a good photo already here.
Click to expand...

Okay, I always called that the idle mixture. Unscrew it all the way out and hit it with carb cleaner, right?
 
For clarification the "idle mixture screw" (ims) as it is correctly referred to, is a fuel screw not an air screw. Ccw adds more fuel etc. I don't know of an automotive carburetor that has an idle mixture screw that meters air.

Mastiff, as recommended previously remove the ims and with the red tube on your carb cleaner blast out the ims opening. Let it sit a few minutes and repeat. I do not recommend direct compressed air as it can cause other issues. If you can regulate down the air pressure use 40 psi max and then use direct compressed air. Remove the bowl and blast out the cavity. Replace the bowl. Be careful with the bowl gasket as they are fragile.

Try this approach a few times. No joy? Replace the ims and set it to 1 1/2 -2 turns out. Remove the fuel inlet hose and block the fuel line start the engine and run the carb dry. Refill the bowl through the inlet with carb cleaner from the spray can. You want the bowl full. Let it set for 5 minutes. Reconnect the fuel line and start it up. This allows the cleaner to see all of the internal passages and loosen the varnish
 
The carb cleaner did the trick, eventually. I blasted into the idle mixture screw hole and fired it up three times and that didn't work, so I did the trick of filling the bowl with carb cleaner and that seemed to work. It idles like a champ again now.

I drove down to the gas station to freshen up the gas and I literally can't get gas into this thing. I dumped about $10 worth down the side of the Scout onto the ground. The steep angle of the filler tube combined with the narrow opening on the plastic tanks is a real problem. But that's for another thread.

Thanks for the help.
 
I agree that filling these 80's is a pita. I have to admit that I don't have any experience filling the plastic variant mine are original steel tanks..

My trick has been moderate the fill rate to about half of full tilt and direct the flow toward the rear of the fill tube. I even turn the nozzle so the curve helps direct it to the rear.
 
Some stations have poorly maintained systems that suck a lot of air into the fuel and this results in a frothy fuel out of the nozzle. When this happens I go to another station. This happens both to the '74 Scout and '71 travelette.
 
After considerable experimentation with jet sizes on the judson setup (using jets michael sent me) I have started drilling out a jet and working up the jet sizes progressively

a 62 jet corresponds to a 1.6mm drill size. To start the test brutally, I went straight to a 2.3mm. Runs great but is far too Rich, but resolves all predetonation issues. This to me proved that the issue was jet related, not timing.

An analyser at idle will only tell you what is going on at idle. Detonation will not occur at idle, but as the judson kicks the cylinder pressure up under load and the advance increases because of manifold vacuum. If you can borrow a portable air-fuel test device, do it in a heartbeat to work out what the issue is under load.

I currently have a 1.7mm jet in the carb. I need to fettle the idle screw, as it runs great but stumbles after sitting for a long time at idle, or in heavy traffic. But again detonation problems are reduced. When I have solved the idling issue, I will try a 1.8mm jet.

Given the different mga engine capacities, there May be a small difference in the jets between the different engines. I can confirm that anything below a 64 jet is too lean for the judson in a 1622, but May be ok for a 1500.

dominic@clancy.ch (the best mga judson site is under clancy.ch)
 
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