Carburetor mounting gaskets

[Phatcat]

Hello again,

Question, the HYGRADE carburetor rebuild kits from Rock Auto come with several carb mounting gaskets for my 84 T4WD. I used the ones that matched what was on the car prior, but this one in the image below has me wondering if this could’ve been a better fit? This definitely was t the first go around for this carb and the PO or mechanics could’ve easily installed the wrong gasket.. Both versions seemed to match up well, and the different version to the one pictured below is on the car, so I only have the one version to show that I did not use. I’m sure the carbs vary a little through the years, but it would be helpful to know why they offer these different gasket selections in the kits?

[dlb]

I looked at this last time I rebuilt a carb and IIRC, the correct gasket has a little tale coming off the hole for either the primary or secondary barrel, and that tale matches the shape of the phenolic spacer. I might have that backwards, maybe it's the base of the carb and not the spacer, but anyway that tale off the barrel hole matches one of them so that's what made me go with that particular gasket.

[Nordical25]

Could different carburetor models have also different carburetor gaskets? I changed mine last winter and found out that top gasket was different compared to middle and below gasket when browsing carb. gaskets from Rockauto. There are a couple of old threads also in this forum and you want to install gaskets, metal plate and bakelite style spacer in correct order correct way up.

[Phatcat]

Yeah, the gasket I showed in the image is for the one immediately below the carb. The ones below the phenolic spacer and intake plenum are obvious-ish. This gasket here seems to fit and align well on the bottom of the carb, as well as the other one I used that came in the kit. It’s weird that there’s several different gaskets for the same purpose and kit.

[Paul]

Here's a diagram I found on the lakelandtoyota site. It appears to show two different options on the lower right.

MF2899K.jpg

The gasket with the tail off the secondary matches the shape of the insulator, as dlb indicated. The other option is open between the primary and secondary barrels, and also looks like it matches it's insulator opening. I'm not familiar with the 21980 heater... mine is built into the insulator as I recall.
When I look at the carburetor mounting gasket options at Rockauto, they all appear open between barrels. I think I chose a gasket from the kit with the tail off the secondary after studying the vacuum passages on the carb base. But I'm starting to wonder what effect the wrong gasket may have on opening of the secondary... might be worth a closer look.

[Nordical25]

That is good to know. Now we have a waterproof explanation why there are several gaskets available. I think that I am running the wrong type for my car but it works fine for me. So it could make a very minor difference but nothing very critical I suppose.

[Phatcat]

Interesting, and great find. I hadn’t had time to actually search the FSM, it may be in there as this appears to be snipped from the manual. I’m now wondering if my secondary is working right too. As when I manually open my throttle to full, the secondary does not appear to open. Now, I just figured this was in “not driving” mode, but there may be something to this? And when rebuilding the carb months back, I did bend on the little foot lever that assists the secondary to open, and I believe after the little foot lever hits and partially opens the linkage, then vacuum pulls the secondary throttle open the rest the way? When doing my rebuild, I simply matched gaskets to what was in there. I remember thinking the bottom intake to phenolic spacer gasket was obvious, but the top gasket between the phenolic spacer and carb was less obvious, and this is the one I suspected could be either one of the two I posted about, and dlb is correct I believe, it depends what spacer you have.. I just had my carb off again too, and don’t remember what shape spacer I have.. ugh. And, I bought a pile of gaskets via rock auto for future endeavors. So hopefully I have the correct ones and everything is perfect. I’ll have to investigate though to confirm. Thanks

[Paul]

I finally got around to try a carb swap, and got to see which gasket I was using:

20240317_100603.jpg

The vacuum passage bolt and secondary vacuum port need to remain open to sample manifold vacuum as pictured.
I thought the 21980 heater was built into the insulator, but I see now it's cemented in place. I would not recommend disturbing it tho. Here's a look at mine:

20240313_145032.jpg

When I did my carb swap, I used the Felpro 60725 available at Rockauto. The packaging claims it replaces 21911, but I think the upper gasket factory number is 21916. The OEM/ interchange numbers for the lower gasket may be confusing too... I believe the factory lower gasket is 21911.
The Hygrade kit includes a gasket market 60725 that looks like the Felpro. Its a thicker gasket that should seal the carb base better than the other, similar looking gaskets in the kit. If you do not have the heater, the gasket with the tail off the secondary (matching the insulator) should be selected from the Hygrade kit.