gas HOG!
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gas HOG!
Hey all, i've got a 83 f-250 with a 351W that i've been fixing up, Just recently got it up and running and took it out for a cruise, all went pretty well except for the fact that apparently it doesn't have overdrive, and it used about 5 gallons of gas in only 35 miles! I've noticed it blows a little white smoke when its just starting up, could my mixture be way too rich or should i look elsewhere? I just recently put a new fuel pump on it , but i wouldn't think that has anything to do with it. Also it looks like it had some kind of exhaust bleed off valve hooked up on the exhaust manifold for carb heat, but its not hooked up anymore and its makin an awful racket. Any suggestions on how to plug it up?
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Joined: Sep 2001
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Sounds like it needs a lot of TLC. Repair the exhaust system with the proper parts, don't just plug things. It sounds like a lot of parts are missing or have been messed with that could explain your low fuel mileage. Bringing all of the engine management systems up to proper operation will improve things.
A small amount of white smoke on startup is called steam, -produced by the combustion of fuel and air. Large quantities of white smoke is usually a coolant leak into the combustion chamber. Huge quantities of heavy white smoke could be automatic transmission fluid being sucked into the induction system.
A small amount of white smoke on startup is called steam, -produced by the combustion of fuel and air. Large quantities of white smoke is usually a coolant leak into the combustion chamber. Huge quantities of heavy white smoke could be automatic transmission fluid being sucked into the induction system.
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Joined: Nov 2004
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From: Asheville, NC
Is there a computer running your engine? If not, and you still have the original ignition system, you probably have no vacuum advance. Thats one gas sucker. Are you running a variable venturi carb on this hog? If the computer is dead, then, theres another suction problem. 
I also have an '83 with a gas loving 351W. They are not known for their thriftiness.
I replaced the carb, distributor and modules, and have doubled my gas mileage. I'm running about 13 mpg. I had a VV carb, a dead computer, and no power at all.
MY truck was custom ordered with a towing package. Tranny cooler, etc. Its running a 4:11 rear axle and a C6 automatic without overdrive. At 70 mph, it is running slightly above 3100 rpm according to the tach. I can handle the gas sucking more now than I could before I bought all the stuff for it.
I also have an '83 with a gas loving 351W. They are not known for their thriftiness.
I replaced the carb, distributor and modules, and have doubled my gas mileage. I'm running about 13 mpg. I had a VV carb, a dead computer, and no power at all.
MY truck was custom ordered with a towing package. Tranny cooler, etc. Its running a 4:11 rear axle and a C6 automatic without overdrive. At 70 mph, it is running slightly above 3100 rpm according to the tach. I can handle the gas sucking more now than I could before I bought all the stuff for it.
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yes it has a computer but its not being used, the motor was swapped out with a rebuilt 78 351W and a DS2 setup, i've got the vacuum advance hooked up but the suction on it is VERY minimal, you can hardly feel it with your finger when it is at high revs. the carb is a motorcraft, but i don't know anything about the carb beyond that. The timing is set deadnuts on zero lined up perfectly with the number one cylinder, with and without the vacuum advance hooked up i notice no difference in performance. I know this is the camper deluxe model, it has a hefty lift kit on it and 33 inch mud tires so i don't imagine that helps the gas too well either. How much do you think it would cost to take it in somewhere and have the carb tuned by someone who knows what there doing? (not me!)
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Joined: Nov 2004
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From: Asheville, NC
Isnt the timing supposed to be set at something like 10 degrees before top dead center with the vac advance unhooked and plugged? Check your engine specs!
The vacuum at the base of the carb is basically there to boost the engine as you rev it up. On mine, the faster the motor runs, the less vacuum is available.
Good luck!
The vacuum at the base of the carb is basically there to boost the engine as you rev it up. On mine, the faster the motor runs, the less vacuum is available.
Good luck!
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New User
Joined: Aug 2006
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From: Eastern Washington state
I agree with Holmesuser about your timing. Not sure about the 351W, but I would guess 8-10 degrees before TDC would change how your engine runs. Also, distributers can stick even with enough vacuum. Take the cap off and see if the rotor moves at all when you suck on the vacuum hose; it should. Good luck -- Garcia
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Tuned
Joined: Oct 2003
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You might try adjusting your timing to where the engine pulls max vacuum. Then adjust your idle circuit until you peak max vacuum.
If your using a timing light unplug the vacuum advance and plug it....set it at 10 degrees btdc.
If you get the timing a little to high the engine will turn over "hard" and "slow".......
If your using a timing light unplug the vacuum advance and plug it....set it at 10 degrees btdc.
If you get the timing a little to high the engine will turn over "hard" and "slow".......
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Try direct vacuum first, because this will give you extra vacuum advance at idle, keeping your spark plugs cleaner over time; however, some motors tend to idle too rough or too fast hooked up direct, in which case, you should run ported vacuum.
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