Technical question about 1972 F carb vacuum

[logic2]

My 72 FJ55 has what appears to be a stock F carb and is running good but I have a few questions about the vacuum connections.

1.) HIGHLIGHTED in RED - I'm not familiar with the vacuum diaphragm on the left side of the carb
(what function does this diaphragm perform) ?

2.) HIGHLIGHTED in PURPLE - Where does the other end of this vacuum hose connect ?
It is currently connected to the Charcoal emissions canister but this does not look correct.

3.) HIGHLIGHTED in BLUE - There is also a place near the base of the carb (also left / driver's side) for a vacuum hose. Where does it go ? It is currently connected to the Distributor (advance).

Thanks for any info.
Mike

 

[LAMBCRUSHER]

canister opens the choke under manifold vacuum. it may very well connect as in the pic. sometimes it's thru a switch or a commutator(doohickey) valve. it should not be connected to the charcoal canister. the base pipe is a source, which is usually connected to a switch, or doohickey. this link might be about what your looking for. seems like the base feeds vacuum to a switch, which it turn thru various means switches vacuum to the distributor diaphragm and/or the choke opener. > Page 048 Land Cruiser Emission Vacuum Piping 3/69-1/79

 

[logic2]

My 72 FJ55 has what appears to be a stock F carb and is running good but I have a few questions about the vacuum connections.

1.) HIGHLIGHTED in RED - I'm not familiar with the vacuum diaphragm on the left side of the carb
(what function does this diaphragm perform) ?

2.) HIGHLIGHTED in PURPLE - Where does the other end of this vacuum hose connect ?
It is currently connected to the Charcoal emissions canister but this does not look correct.

3.) HIGHLIGHTED in BLUE - There is also a place near the base of the carb (also left / driver's side) for a vacuum hose. Where does it go ? It is currently connected to the Distributor (advance).

Thanks for any info.
Mike
View attachment 1423512

Should I block of

canister opens the choke under manifold vacuum. it may very well connect as in the pic. sometimes it's thru a switch or a commutator(doohickey) valve. it should not be connected to the charcoal canister. the base pipe is a source, which is usually connected to a switch, or doohickey. this link might be about what your looking for. seems like the base feeds vacuum to a switch, which it turn thru various means switches vacuum to the distributor diaphragm and/or the choke opener. > Page 048 Land Cruiser Emission Vacuum Piping 3/69-1/79

Good info and makes sense.
Thanks !

 

[LAMBCRUSHER]

I am not certain where the charcoal canister hooks in on that year, but someone here does for sure. you could prolly run it directly to the air cleaner housing for now, so it burns the vapors when the engine is running...if you have a charcoal canister, you shouldn't plug it, as it is a means for the tank to vent and not burst. it gets its vapors thru the vapor seperator deal, and was meant to seperate and return raw fuel from vapor, and feed vapor to the engine while it ran to minimize the atmospheric release. or something.

 

[4Cruisers]

Center picture might help, even though it's hard to see what's what from that angle:

 

[thebigredrocker]

The red linkage rod is connected to the throttle positioner and vacuum diaphram(sometimes called "choke pull-off diaphram"). Turning the screw in on the throttle positioner (with vehicle off) will crack open the primary throttle plate. Once your engine is running, vacuum sucks that diaphram which pulls that rod and negates the initial throttle positioner setting. Your throttle is now cracked open by the all important "idle speed screw"

The blue vacuum port is the port normally used for the diaphram "choke pull-off"

None of my cruisers have emission gear, so I don't have anything to add there.

USA 72's came with a vacuum retard distributor. If your rig still has a retard dizzy it is advised by FJ40Jim(a guru) to not hook any vacuum to your dizzy. Just cap the diaphram and set your advance to 10 degrees TDC. It is my belief his method will help your engine w/retard dizzy run better than it did from the factory.

If someone has added a Vac Advance dizzy then I don't think that port on the drivers side is best. That is under your secondary throttle plate which is often closed. (I could be wrong though, I'm no expert) The best spot for a vac advance signal is on the passenger side carb base. Just below the primary throttle plate. 65swb45 & FJ40Jim would be the best guys to have add an advance port. The other spot I've seen used is a nipple that threads into the intake manifold.

To tell what type dizzy you have: remove the dizzy cap, hook a vac line to the dizzy diaphram and suck on the other end. If the plate inside the dizzy moves clockwise, you have a retarded advancer. If the plate rotates counter-clock, you have the more desireable advance type dizzy.

The carb picture you posted doesn't have the choke pull-off linkage rod present. I posted one of mine that does below. If your carb does have this linkage, here's what it does:
During cold starts, you pull your choke cable which (hopefully) closes the choke plate on the primary side of your carb. This plate chokes off air flow, so that your combustion chambers are geting mostly fuel(rich condition). Once the spark ignites the fuel, your engine is running and now has more suction or vacuum. The vacuum now present in your running engine sucks that diaphram which pulls the choke pull-off linkage. Without you having to touch the choke cable during warm up, the linkage slighly pulls open the spring loaded choke plate. This allows slightly more air to mix with the fuel during warm-up(leaner). You can bend that linkage to the desired amount of pull-off. Once warm, you push your choke cable in and now the diaphram's job is done.

 

[4Cruisers]

Much better: