The hot weather is causing the gas to boil in the carburetor.
I bypassed the hot water spacer plate, and it helped some, it just wont boil quite as fast.
I want to try a Phenolic spacer, but cant find one for a 2 barrel carburetor.
Do you know where to find this?

 

Summit- Holley 17-72. $60.95. Also Canton Racing. 85-158. $59.95 If I need something, Summit.generally has it!

 

ebay dirt cheap and any size ,thickness , open , 4 port whatever .

 

Stay away from the TransDapt spacers for the Holley 2300. They DO NOT work on the Autolite/Motorcraft 2100/2150s. I can post pics after I get home tonight if you want to see what I mean.

eric72xlt:
That Holley 17-72 looks PERFECT. Are you running one with a 2100/2150? My 73 has the same boiling problem and I've been trying to find a spacer that is confirmed to work.

Thanks!

 

No, I'm not using one. I am having the same problem though. I'm planning on putting a 4 barrel carb /intake on soon, so I'm just living with it for now.

 

Yeah, not 100% sure I want to fork over $60 to "try it" but I do have $40 worth of TransDapt spacer to return + Summit Bucks... maybe I'll order one and report back later.

To the OP: I know eliminating my EGR helped the carb boiling problem as well. I used a spacer from a 2v Mustang and blocked the EGR port in the manifold with a 10mm bolt nub and some JBWeld. FelPro makes a really thick gasket that looks like its made of fiberboard with plastic crush-resistant spacers around the bolt holes. I put one between the Mustang spacer and the carb and it seems to help. The combination of the 3 things has helped significantly, but its still not enough on a really hot day. I can get the PN if you want to give it a shot.

Hope that helps!

 

Just got the thick FelPro gasket too, and getting ready to test'er out.

 

I had a similar problem with driving and restarts on hot days.

My fix was:
------------
1) Changed to 180 F thermostat
2) Wrapped the metal fuel line to the carburetor with rubber fuel hose(insulation from radiant heat)
3) Removed the heater hoses from the 1" spacer/warmer plate under the carburetor.

 

TransDapt 2136 1/2" spacer with Autolite:

I didn't get it perfectly centered, but you get the idea.

Some random old 1/2" phenolic spacer with Autolite:

Notice it covers the openings?

Carb is a 1.08 bore for my brothers Bronco. Keep an eye on these two points when putting spacers under 2100/2150 carbs. This is why the Jeep/AMC guys have so many problems when retrofitting a Ford carb. The MrGasket Holley 2300 adapter/spacer they use has the same problem as this TransDapt.

Turns out Summit owes me $85 in returns and I have $40 SummitBucks burning a hole in my pocket. I'll probably buy that Holley 17-72 and give it a shot and report back next week.

 

The thick FelPro gasket made a huge improvement. The auto parts only had one. Probably one more on the other side of the bypassed hot water plate would be even better, but it would take longer studs.

 

thanks for the info , stuff like that is always good to keep in the brain

 

Back in the day...when I was young and chased dinosaurs...we used to use cork carb gaskets (single and double) and carb spacers cut from a good chunk of hard wood to insulate the carb from a hot intake manifold. Worked then, long before phenolic stuff was created...should work now, too. Bigger question is why is your engine running hot enough to boil the gas in the carb?

 

I would like to ask where you found a suitable Autolite phenolic 2 barrel carb gasket that did not have the leak issues. I have been looking online for one but can not find any specific info about one working with an Autolite 2100 on a 390. Seems like a 1/2" would be best for replacing the stock water inlet plate so you can use the standard bolts.

 

I know I am a late arrival but I'm with Tim, I knew 4 barrels on alum manifolds were an issue but was unaware of 2 barrels.

I think I got my spacer from Advance Auto, but it's been a while.




John

 

Something else that may help. I once saw an aluminum plate that was made as large as possible to clear the throttle linkage and fuel line to act as a heat sink. The guy made it himself by using the gasket as a template. The other thing that really helps is to block off the heat passages under the manifold if you are in a real hot section of the country but not the most practical for cold climates.
Many years back I saw a small Japanese car that had a small fan mounted near the carbureator! Kenny Nunez