my exhaust reaks of gasoline: amc 304 with holley 2bbl

[rustybrownCJ]

Hey thanks for looking! I'm choking on my own exhaust fumes. My jeep reeks of gasoline and so does my clothes when I come home. I can smell it right now. My Jeep runs great but I sure could use some help getting it to stop running so rich. The tail pipes even spatter oil/unburned fuel on the wall in my garage.

1980 Jeep CJ7 w/ AMC 304
Headers, dual exhaust, Flow masters, tailpipes that run to the back, no cats.
Holley 2 bbl model 4412-3, manual choke, around 500 cfm. K&N shroud intake.
I live at 9,000 feet, The timing has been advanced.

I'm not real sure where to start with this thing. I have done some research on here and so far I start to wonder maybe:

I could change the spark plug gap?
It could need a fuel pressure regulator?
It could need jets that didn't come with the carb?
I could just adjust it with a screw driver?

My jeep has been this way for over 10 years. The carb was installed by a mechanic who also owns a jeep. Please help me

Rusty brown CJ

 

[Torxhead]

Holley does make a great carb, and from what I remember they are quite adjustable. To start with there is a float adjustment and too high of a float level will make for a richer mixture. There are jets that come in different sizes and a few other items that can help you like parts to help it better offroad when going up and down steep hills. This does involve partial carb disassembly, so you will probably need some help with that in the form of Holley manuals and maybe some help on the internet. I don't think a spark plug gap change can help here which should be a .035" unless you have the "Team Rush" upgrade which can allow you to open it up as far as .045". A pressure regulator won't help here either, you should be getting around 4 p.s.i., and that should be fine.

 

[csuengr]

You need to change your jets to a smaller size. Adjusting timing for altitude is just one step. You should also throw that Holley in the trash and get a good altitude compensating Motorcraft 2150 carb.

The black spatter on the wall is not gas and oil. It's water droplets that dissolve soot in your exhaust system and is blown out. My mom's Mercedes does the same thing.

Remember HC + O2 --> CO2 + H2O

 

[tarry99]

Hey thanks for looking! I'm choking on my own exhaust fumes. My jeep reeks of gasoline and so does my clothes when I come home. I can smell it right now. My Jeep runs great but I sure could use some help getting it to stop running so rich. The tail pipes even spatter oil/unburned fuel on the wall in my garage.

1980 Jeep CJ7 w/ AMC 304
Headers, dual exhaust, Flow masters, tailpipes that run to the back, no cats.
Holley 2 bbl model 4412-3, manual choke, around 500 cfm. K&N shroud intake.
I live at 9,000 feet, The timing has been advanced.

I'm not real sure where to start with this thing. I have done some research on here and so far I start to wonder maybe:

I could change the spark plug gap?
It could need a fuel pressure regulator?
It could need jets that didn't come with the carb?
I could just adjust it with a screw driver?

My jeep has been this way for over 10 years. The carb was installed by a mechanic who also owns a jeep. Please help me

Rusty brown CJ

At 9000 ft as csuenger suggested , It seems you need to lean ( take fuel away) from the system via a Jet change.

I assume that you live , work and play at that altitude all the time..........if your driving needs take you to lower altitudes frequently then perhaps a good Fuel Injection system with a capable ECM that will manage fuel based on altitude as you travel may be the ticket.

One last thing..... the altitude that is posted for your town is what we call the "mean" altitude or the actual altitude above sea level.......but for the most part at all elevations the "adjusted altitude" can and will be several thousand feet above or below that based on temperature and barometric pressure for any given day or time. Perhaps you have noticed that some days it may seem to run better than other days..........that's why. Lower adjusted altitude there are more molecules of Oxygen versus higher.
A modern Fuel Injection system is something that you might want to consider.
Note: Just did a quick calculation based on Weather Info for your town right now which shows: 45 degrees, Baro: 30.46, humidity 20% dew point 7 and the adjusted altitude right now is: 9685.......

 

[rustybrownCJ]

Thanks for the response guys! So far it looks like the best place to start is to check the float adjustment. If it looks good I could order a Jet kit from Holley for like $55.

Everyone is saying to go with that Motocraft. I can appreciate that since that's probably the original part from that ended up in the garbage sice it was from 1980.

I suppose I will stick with this Holley for now and I remember ending up with it because I need a manual choke. It gets really cold here in Colorado and I think I burnt up the heat choke because of this. I probably will do most of my wheeling up at a even higher or slightly lower elevation. For now I just don't want to reek when I go to the grocery store.

Do any of you guys think that my needs are achievable with this carb?

Is re jetting a carburetor a difficult task? How do I know what size jets I have? Do I really buy a whole kit just for 2 jets? It seems to be a trial and error process.

Thanks again!
Rusty brown CJ

 

[csuengr]

You can call the Holley tech line and they should be able to find you the correct jets.

Holley's are good street carbs. They hate offroad though. I ran an altitude compensating 2150 on my Jeep and it ran really well from 3000ft to 13,000ft. Held good idle. It would start at 17 below and I never burned up a choke. I don't think you can burn up a choke.

 

[Jimbos76cj]

Check your plugs to make sure you dont have a dead cylinder. that would alow unburnt fuel into your exhaust. If you havent had your carb rebuilt in 10 years it might me time for a good rfbuild or replacement. Sticky float, miss adjusted float, bad needle valves etc etc etc can cause you to have the fuel issue.

If you have a temp gun you can fire up the motor and hit each exhaust runned close to the head with the temp gun to make sure you dont have a dead cylinder.

The sell manual conversions for the 2150 or 2100 carbs.

 

[Jimbos76cj]

Oh.. also check your cylinder pressure or do a leak down test if you have a leak in a intake valve it will pull in more fuel

 

[Torxhead]

RustybrownCJ, The jet sizes are indicated by the numbers located on them. You will have to remove the float bowl to get at them. This means replacing the float bowl gaskets at least and a smaller size will mean a smaller diameter hole on the jet. As already suggested, the Holley tech line sounds like a good start.