The Stovebolt Site Forums The Shop Area Engine Shop Raw Gas in exhaust Help

Hey. I was wondering if anyone has had this problem or has heard of it. I have a 61 with a 283 and a 2g 2barrel carb. I had a problem with the float sticking I believe because there was gas pooring out of the carb after about 10 seconds of running. I replaced the float and problem solved. The truck had a bad hesitation when you stepped on the gas before and after the float so I installed an hei which impoved but did't corrent the problem. I dialed in the air/idle setting using a portable tac (i don't have a vacume gage. Truck ran almost perfect. After a couple of days in the garage i noticed it putting off a very strong gas smell. Turns out I now have gas coming out of my passenger side exhaust pipe. I tried leining it back out and no change. Any Ideas? Carb is clean and not very old at all to begin with. Like I said the truck is running nearly perfect so its not missing a cylinder to give me raw gas. Also the oil is clean so no gas is pumping into the pan thanks for any help in advance

If I had to guess I'd say you have a dead cylinder on the right side of the engine. For gas to get into the exhaust it must travel up into the exhaust valve. Otherwise it would travel south into the oil pan.

Either you are running so rich that lots of raw gas is not burnt while the engine is running (this is very possible, but you'd see the issue in both pipes) or you have a miss that you are having trouble finding.

Is it possible you have a leaking fuel line? I would think that if the engine was was any gas within the engine would evaporate away and not leak out. Maybe the line going to the fuel pump is leaking?

Ok. I am almost positive the problem is in the carb, which I don't have a ton of experience with. The gas is coming out of both pipes just less noticable on the drivers side. Maybe because of the way the pipes are bent. I adjusted the carb following my manual which said to adjust the idle mixture screws to achieve max idle and vacuem. I went for max idle becouse i have a tac but no vacuem gage. as I said this made the truck run much better but this problem happened. I have since backed off the screws at least two turns and I am still getting gas although I don't think it is as much. Is there something else I am overlooking

Not sure what carb your running - I always turned the screw in (while truck was running) until it started to stumble. Then backed it off 1/2 turn or just barely into a good idle. This should be a good set up for every day use.

Running a 2g carb. Am I right that backing the screws out leins it out?

I always thought turning them in leaned them out - but i was proven wrong on my tractor this month. I figured it out by turning the screw in until I had black smoke coming out. Then the light bulb went off. I then turned it out until it ran good.

I'm not sure how yours works so turn it slowly until the engine starts to act up. If it is too rich you should be able to smell it or see black smoke. If it is too lean the engine will start to sputter & may die.

Just go slow - take small 1/4 turns until you get it figured out. You are on the right track - almost there!

How are your plugs? If the carb is constantly rich, they should show black and sooty.

Do we know that it's only running rich through the idle circuit (ie: idle speed crew)? Or is it running rich through the whole spectrum? I thought a float that was set too high (even by a 1/16th inch) could cause rich running?

I also thought the screws turned IN to lean, and OUT to enrichen. However, my experience is ONLY with 216/235 engines. but I thought the old standby "fully - seated, then 1 1/2 to 2 1/2 turns out" was universal?

-Michael

Thanks Guys, I am going to pull the carb again and recheck the float. After reading my book again I see that there are two adjustments to make on the float. On for hieght and one for drop. I only did the hieght. It also says that the 1 1/2 turns out is a good starting point. It also says adjust them in until you get a idle drop and the back them out 1/4 turn for a "lien drop". So I am going to try all of these and recheck my timing just in case and I will let everyone know. Thanks alot for the tips

Ok. I think I need to rejet. Some info I found said basic rule of thumb is that if the idle screw is more that 2 1/2 turns out then the jet is to lean or two small and if it less than 1 1/2 turns out then it is to rich or to large. I have mine all the way in now and it is idling well and has good throttle responce but is still showing some black smoke and a few small drops of gas will show on my hand if I hold it in front of the pipes.