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Gas vapors expell out of carb for 10 mins after i shut the truck off. This goes along with my other issue i guess. The engine continues to start and idle great, but it will not handel an acceleration from the throttle unless you increase the throttle very very slowly, and then it does want to regain idle for a couple of mins. Its an inline six 65 chevy. I just bought it and it ran perfect for the first 45 miles or so then with out any changes to the truck it just cut off after shutting it off for 30 mins to go into a store. The truck made it 30 feet and quit responding to the throttle and shut off. It happend without any pre warnings. It did not show any signs there was an issue, not even a noise difference or drive difference from when i turned it off to go to the store to strating back up to leave. Some people have mentioned maybe its a stuck valve, but it hard to believe it would be that with out some sign, at least a small one. It was running perfect. Thats what made me think maybe a carb or vacuum issue. Here is a list of my trouble shooting and the stuff i've done so far. Also, i have a glass fuel filter and i see that it stays full of clean fuel so i dont think its a clog or the fuel pump.

1. I put a new carburetor on it
2. 6 new spark plugs
3. new fuel filter
4. distributor looks good
5. distributor does not have a vacuum hose port
6. the carburetor has a vacant port next to the fuel/air mixture screw that makes a sucking sound when running, but there is no where to run a vacuum hose that i can tell. I have tried plugging the hole but it makes no difference in condition.
7. when the throttle is pushed at normal or fast speed it makes a giant air sucking noise and spits blacksmoke out the rear.
8. i pulled the valve cover off and the rockers look good.

please help

Hy mswilkes65Chevy, firstly plug that leaking port on the carb. How many miles on this engine? Check the dwell and then check the timing. As far as I know your distributer should have a vacuum advance on it.

i have plugged the port, the engine has about 5000 miles on it, the timing is good, and i dont know what the dwell is. Where would the vacuum advance be, i cant find it or i dont know what i am looking for. thanks for the help

the vacumn advance goes down from carb to the dist. it should be a small hose smaller than fuel line. this is a rochester b right on a 65 chevy? if you have a hei dist you woun't have to worry about the dwell setting but you will if you still have points. have you checked how much vacumn you are pulling and set the timing with the vacumn gauge? might give it a try, might find out if it timing or vac leak or what. you can't always trust a new carb too. good luck. hr

its a holley 1 barrell carb, this engine is not the orginal inline six. This one cam out of a boat new, it is a gm motor.

where is this vacuum advance at, cause i cannot find one anywhere on the distributor itself

the vacuum advance is a cone shaped unit on the side of the dist, it goes down to a tip for the vac line. if you take the cap off you can see the mechanism it operates. maybe since this is for a boat it didn't have one. i am not familar with them but if it doesn't have it i would think you will need to get a dist with one on it to work in a truck. maybe the boat only opperates at fixed rpm's and doesn't need it. also don't some boat engines spin in reverse rotation? good luck.

thanks, the only thing thats keeps puzzeling me is the truck ran great for 45 miles.

My guess is....Too rich and timing not advanced/advancing far enough.

thanks

OK. You got MY attention when you said the motor is out of a boat! What is the year model of the engine and the displacement? Did the distributor come with the engine?
If it did, most industrial engines used a governor and the distributor does not have a vaccume advance on it.

Also to note: The 250ci. industrial engines used a higher compression ratio ( 8.7 : 1 ) and larger valves.
With the HEI distributor upgrade, a 2 bbl carb, and crane cam, they are a real hoss of a motor!

I will find thoes answers for you. I just bought the truck 3 weeks ago and i am not sure the motor size or year. It does say GM12 on it with some other numbers. I would imagine the distributor came with the engine. But this still begs the questions or statement that it ran perfect for the firast 45 miles i owned it, and then abrubtly quit. Thanks for your interest maybe we can get this figued out.

Since marine engines do not change throttle loads like a car, there's no need for a vacuum advance. I'd suggest getting a regular distributor, a HEI if possible, as the marine dizzy won't work well in a road vehicle. It sounds like you've got some major carburetor problems that came on pretty suddenly, possibly a flooding situation caused by dirt under the needle valve, etc.
Jerry

It can't be a carb problem i have put a new one on since it started. I adjusted the timing a little richer last night and it has vastly improved the problem. I can know drive it at least. It still has a little vacuum sound when the pedal is pressed real quick, but I think we are getting closer. I am going to make sure i get the engine details, and then i will adjust the timing properly and reset the points and see if that fine tunes it back to the way it was running. I will also look twoards getting an automotive distributor once i do get the engine details. Thanks for the help we are so close.

Have you checked your point gap. It may have slipped on you.

here is the big reveal

The motor did come out of a boat, it is the same motor as the 67 chevy bisycane, except that the distributor does not have a vacuum advance like HotRod Lincoln said. It is a 250 ci motor. So for the most part it is the same as the 292 that was in the truck orginally, except the block on the 250 is 2" shorter.

I am going to buy a distributor for a 67 bisycane (37 dollars) and then i should have the vacuum advance port for the caburetor hook up done. Then i am going to redo the timing and reset the point gap.

Hopefully my last question is what are you guys setting the point gap and spark plugs at for the 250 or 292 enignes.

I'm not saying this because I have one for sale. I believe most of the fellow stovebolters will agree. Now would be a good time to put an HEI dist. in, or at least an electronic ign. conversion kit. You can probably find one locally.

I just drove it to the gas station and it drove good but it is blowing a light black smoke out of the back. Any ideas on what adjustment i need to make. I am thinking maybe its the fuel/air mixture screw on the carb.

Thanks Again

well from what i understand white to light to lt blue smoke is bad rings, but black smoke usually indicates over rich carb you might try leaning the mixture out some and see if that dosn't cure the prob "much better to have black smoke than white lol"

thanks i will update later

The mixture screw only works at idle, to change off-idle mixture you will need to re-jet.
I would get some miles on it before worrying to much. It could be loaded up for all the tuning you have been doing. Get a HEI or new points distributor, get it timed where it doesn't ping under a medium load (6-10 degree) then get it out on the highway. A good 10 mile drive will clean out a lot crud and dry out the plugs. If it still smokes, we can go from there. Joe

Joe,

Great Advice. I will do that this week and update the post accordingly. Thanks for help.