1984 Toyota Hi lux pickup 4x4 with 22R engine. I replaced all smaller vacuum lines and when I took the two that come out of the bottom of carburetor on passenger side and go to sensors, there was fuel in the vacuum lines. The engine runs ruff, black exhaust and smells almost like alcohol.

 

Aisin carburetor probably needs a rebuild. All of those carb-attached lines vacuum into the engine so it's odd that fuel would get back up into them. Must be getting through something it's not supposed to in there.
The other three issues, runs rough - black smoke - exhaust smells like alcohol, are all rich excess gas symptoms. LIkely linked to the carb malfunctioning.

Depending on how long it's run this way, your catalytic converter is also likely to be clogged.

 

I found fuel in my vacum lines and traced it to a ruptured vacum diafram on the side of the carb. I decided on replacing mine with a Weber. Or rebuild yours.

 

Thanks for the info,I'll start looking into a rebuild or replacement.

 

As a side note. If you plan on keeping your truck long term and have the bucks a Brand New carburetor is still probably available. I found one for mine for just under $700.00. And that was on a discount Toyota parts site. Still in stock. Use your full model number that is pop divided to the firewall, that is a good mine of info as it gives the distinct model and build date. I found that out the hard way. I have rebuilt carbs for years for myself. If the throttle shafts are OK and not worn really bad it is a simple rebuild . but if the throttle shaft bores are shot then they have to be drilled out and bushings installed and reamed to size. Not cheap work. And rebuild parts are getting harder to find.

 

What causes the fuel to be in that particular vacuum line is a ruptured Auxiliary Acceleration Pump (AAP) Diaphragm. When the diaphragm ruptures it allows fuel to go through that vac line to the engine, usually the #1 cylinder. If you pull the #1 spark plug you will likely find a lot of carbon on it. This is the cause of the rough running & black exhaust, because too much fuel is getting into the engine (over-rich condition) & not being burned. The Alcohol smell is probably due to your running todays 10% Ethanol Blend Gasoline in it. Ethanol is pretty rough on rubber parts that were not made to handle it, & this is probably what caused the diaphragm to fail.

The AAP is only supposed to work when the engine is cold. It is controlled by a Temp controlled vacuum valve that send vacuum to it which opens an additional passage in the carb to allow more fuel to flow. Once the engine warm up it shuts off the vacuum & the diaphragm closes, blocking off the passage. You do not need this item to be functional; most people just cap off the vac port to the diaphragm housing.

The AAP diaphragm is not available on the market as a separate purchase for reasonable money but it does come with carb rebuild kits like these: https://www.rockauto.com/en/catalog/...epair+kit,5964

Mwhite49 is right, Brand new OEM (Aisin) carbs are still available from Toyota for about the price he states, but you can get a pro rebuilt OEM carb with a warranty for less than $200 from National Carb here: http://www.nationalcarburetors.com/l...partnum=toy505
I got a rebuilt Aisin carb from them for my '78. The rebuild quality is excellent & the carb works great. I have been very pleased with it. They also list a "NEW" carb but I don't think I would recommend it. It is not a new Aisin & is likely China-built. I have never been able to get a China-built carb to run right on a vehicle, only on lawnmowers.

Other thought about Ethanol Blend Gas - You really need to check out your rubber fuel lines & likely replace them with new, as well as your fuel filter. Ethanol will break down the old rubber. Check out your fuel filter, it should be located just forward of the gas tank. If you can see a fair amount of black specks in the bottom of it, your fuel lines are breaking down from the Ethanol. Those rubber particles, if they get past the filter, can clog up idle passages in a carb in a hurry.

 

Thanks for the info, I'll check out the carb from National Carb

 

Added Info - National Carb uses ethanol tolerant parts in all of their rebuilds, so getting a rebult carb from them you do not have to worry about Ethanol blended gas causing a prob with the carb again down the road.

 

You shouldn't because the newer rebuild kits are now coming with ethanol friendly materials. So make sure you ask whether it's old stock or new.

 

thanks for all the info, I had the carborator rebuilt, the truck runs great again.