1980 FJ40 Carb Rebuild - Questions

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Well, my carb kit arrived last night, and my carb went back together without a hitch. I have learned a lot about my cruiser and have enjoyed the process... I will get it installed tomorrow and will give it a shot to see how I did! THANK YOU PIN_HEAD for the video's. They gave me the confidence to tackle this myself. And with my FSM in hand, I took on the task! Thanks to everyone else for the comments and suggestions. I hope I will have no other issues... Knock on wood..!!!

I have a question however that has been bothering me. It is about the gasket kit I received and installed versus' what was on the carb top, when I tore it down. The top cover gasket shown in this picture is the OLD gasket... If you look at the area below where the float is installed it is all blacked out and is part of this gasket. Some of the holes themselves are partially blocked by this by this gasket also. I am not sure if this was "properly" installed by the PO or whomever, but I also noticed the isolator gaskets that were used on it, were put on backwards and definitely holes were blocked in the isolator. So not sure if that caused ANY issues!

My NEW gasket for the top was missing the inside portion or everything below the float. It was basically everything around the perimeter of the lid and across the center section. Could this have cause the issues the PO apparently experienced that resulted in him cutting the Idle Solenoid off like he did? I ask this because I am hoping it would, and I will have corrected ANY issues that were stated above, that I might experience because the idle solenoid was cut! Finger's crossed!!!

Just checking... ANY THOUGHTS...?

1980 FJ40 Carb - Inside of Top.jpeg.webp
 
The 'open' design gasket from the rebuild kit should work just fine.

I often say that disassembling a carb is like reading a cheap detective novel. If you're attentive, it doesn't take much to solve the mystery. I think you've found your culprit in the flip-flopped gasket. That would definitely have disrupted the idle circuit.

Keep us posted.

Mark
 
Well, I got it all mounted up yesterday and got all the vac lines reconnected etc. I cranked the engine for about 5 secs twice and pulled the choke on and pumped the pedal twice and she fired right up... WOW, she ran great.... NO ISSUES... Well, only one, the idle speed was adjusted too low. I had to call it quits yesterday cause the wife had some honey-do's I needed to do to keep her happy... :)

So, today I set out to adjust the idle seed and WOW, absolutely no issues at all.... The engine is running the best it has run in the little over a year I have had it... Thought it ran good before, but man I could feel the difference what I drove it too...:bounce::bounce2::bounce::bounce2:

Thanks Pin_Head and Mark and everyone else who commented and help me accomplish this "simple" task... lol Just glad I had no issues like Spike Strip was mentioning I could have been faced with especially since someone cut the Idle Solenoid instead if figuring out why a "rebuilt" carb would not idle... They would have found the upside down gasket I found during disassembly on the isolator plate... Fun times now... I missed a trip this weekend with the Copper State Cruisers, but I did not want to rush my install or the rebuild as this was my first carb rebuild. I am glad I chose to take it steady and slow checking ALL my work!! :steer::steer:
 
Way to go, they really are simpler than most think. The problem is sometimes there is just something plugged on a carb, any carb for that matter, or something is just screwed up or wore out, like you idle solenoid, that can make a person pull out their hair trying to fix something.

I learned cruiser carbs early on, my 40 sat most the year for many years and was only used to plow snow in the winter when I was kid. Most falls dad would pull the carb and stick a kit in it cause it had crudded up sitting, from that I've been able to tackle about any carb I see. With that said, I have a 75 high altitude carb I have messed with for years, no matter how many times I have rebuilt it and tuned on it, it will never idle smoothly, I've never been able to figure it out, sometimes I think they are just shot, seems like the throttle shafts are gone on it, too much play and air leakage.
 
DTSkyCop said:
Additional photos:

View attachment 1213077
Click to expand...

I'm really curious as to what the piece at the top right of this picture, attached with two screws is.

I have a 1979 FJ40, and my carb just has two plugs covering the vacuum ports on that part, which makes me think it's useless (I took all the smog stuff off I thought was safe to years ago).

If this part is not needed, I'd like to keep it off the carb.
 
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mountainman38 said:
I'm really curious as to what the piece at the top right of this picture, attached with two screws is.

I have a 1979 FJ40, and my carb just has two plugs covering the vacuum ports on that part, which makes me think it's useless (I took all the smog stuff off I thought was safe to years ago).

If this part is not needed, I'd like to keep it off the carb.
Click to expand...
Did you ever get an answer to "what that part is"? Currently rebuilding my 1979 carb.
 

Carburettor Additional Systems (Automobile)

9.15. Carburettor Additional Systems One or more add-on devices are be used with the carburettor to improve economy, driveability, and emission control. Most commonly used devices are discussed below. 9.15.1. Hot-idle Compensator Valve High air temperature at carburettor inlet causes […]
what-when-how.com what-when-how.com

It looks like you are just about ready to dip the parts. Just don’t dip any rubber or plastic parts.
 
Pin_Head said:

Carburettor Additional Systems (Automobile)

9.15. Carburettor Additional Systems One or more add-on devices are be used with the carburettor to improve economy, driveability, and emission control. Most commonly used devices are discussed below. 9.15.1. Hot-idle Compensator Valve High air temperature at carburettor inlet causes […]
what-when-how.com what-when-how.com

It looks like you are just about ready to dip the parts. Just don’t dip any rubber or plastic parts.
Click to expand...
My rig is desmoged do I need the hot idel compensator? I put it back on already just wondering if it actually does anything now?
 
Badad said:
My rig is desmoged do I need the hot idel compensator? I put it back on already just wondering if it actually does anything now?
Click to expand...

Pin_Head said:

Carburettor Additional Systems (Automobile)

9.15. Carburettor Additional Systems One or more add-on devices are be used with the carburettor to improve economy, driveability, and emission control. Most commonly used devices are discussed below. 9.15.1. Hot-idle Compensator Valve High air temperature at carburettor inlet causes […]
what-when-how.com what-when-how.com

It looks like you are just about ready to dip the parts. Just don’t dip any rubber or plastic parts.
Click to expand...
One more question if you don't mind. Do I install all the gaskets dry or do I need to use an adhesive of some type. Total of 4 gaskets. Thanks in advance
 
mountainman38 said:
I'm really curious as to what the piece at the top right of this picture, attached with two screws is.

I have a 1979 FJ40, and my carb just has two plugs covering the vacuum ports on that part, which makes me think it's useless (I took all the smog stuff off I thought was safe to years ago).

If this part is not needed, I'd like to keep it off the carb.
Click to expand...
The part is referred to as a “thermostatic valve” in the parts diagram 21335-61021 1/79 to 7/80. The jury is still out as to its function.
 
I think pinheads “carburettor additional systems (automotive)” nails it. My thermostatic/compensator valve is hooked up. It draws clean air from a pipe on the air cleaner, through the valve, to a small pipe below the carb on the phenolic insulator to manifold vacuum.
 
Anyone know what these holes circled in red are for? I know they are supposed to link up to both emulsifiers via an o-ring but that's about as far as my knowledge goes about their functionality...

1643768165322.webp
 
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