Truck cranks, but will not turn over

BallzF250

Well-Known Member
Joined
Feb 24, 2010
Location
Wilmington
Problem: Truck cranks, but will not turn over.

So I picked up a '79 F-150 with a 400m and a 4spd in it last weekend. I knew it didn't run, but was told that it would just need a battery/starter and that it would crank right up (apparently I was lied to...some learn the hard way...but regardless, I like little projects). Well I've replaced the battery, starter, and starter solenoid. It was wired incorrectly by the previous owner (PO), but I'm about 98% sure I've got it wired correctly now. There are a few issues remaining but those are issues like solding proper connectors to wire ends and trying to start again...but I'm fairly confident this won't solve me problem.

The truck had been sitting for almost a year before I came along to rescue it. The PO told me the gas may be bad in it since it had been sitting for a year basically. I don't know about the gas issue...always thought it would take longer than a year. I was in a bit of a hurry the other day when I got everything new put in and was trying to start it, so there are still things I didn't get a chance to check.

It has a manual choke and I'm assuming this has to be open to start, correct?

Here's a list of things I still have in mind to check:
--Check to make sure there is fuel (I can see fuel bubbling a little in the fuel filter capsule and can see if squirting into the carb...so I'm assuming there's fuel) (I have a new fuel filter, but have not installed it yet).
--Check to see if I have spark (never actually done this before...unscrew the spark plug, put the wire back on, hold plug near engine block, and crank to see spark...correct?) (probably going to get new plugs and wires also).
--Check and possibly replace or bypass the Clutch Safety Switch.
--Check and possibly replace Ignition Control Module (not sure how to check, may just replace since they aren't too expensive).
--Check points and rotor in distributor (what am I looking for here?).
--Check firing order (assuming since starting system was wired incorrectly, plug wires could be incorrect as well...didn't think of this until after I was away from the truck...later that night laying in bed actually...random huh).

When I was trying to start it, within the first few attempts the carb had about a 6" fire ball shoot out the top of it. Looked really cool...but don't know if that's a bad sign or not. Say anything to anyone? Once I finally decided to give up on trying to start it, I could see a little puddle of gas on the intake manifold under the carb...not sure what that's from if I flooded it or if there is something loose that needs to be tightened. I have a carb rebuild kit, so I'm planning on cleaning and rebuilding the carb...I just wanted to hear it run before I started doing to much...or should I get that taken care of first?

I'm looking for answers to my various questions, suggestions on other things that I should probably check, suggestions on order of things to check, etc. I'm very electrically inclined and slightly mechanically inclined...but I can manage with most things.

Thanks!
 
Do you mean it will turn over, but not crank?......It sounds like it's jumped timing. Fix the gas leak first so you don't burn/blow up your truck!! AND get a service manual for that specific truck/motor if you intend to keep it and make your own repairs.
 
Rebuil the carb and replace all the rubber line and fuel filters. Also take and clean our or replace you tank. I know thats sounds like a lot of work but if you don't do it your carb will just get gummed up again down the road. I'd also go ahead and change the plugs, wire, cap and rotor. Checking the ign control module is simple if she runs it's good, if not and everything else is good it's bad. There is no grey area with those.
 
However its said...the truck won't start but the starter is engaging the flywheel and turning the motor. I do have a Haynes manual for the truck and plan on doing as much of the work as I can. I work nights so I wasn't about to get anything done today. Pretty much sounds like I need to just start with rebuilding the carb. I'll try to get to that this week.
 
This is a process I use to start a motor that has been apart or seting awhile.
1. Take out spark plugs. They should be light brown without rust
2. Find timing marks on front crank pulley. Connect timing light.
3. Spin motor with starter. It should spin fast enough to get oil pressure. If timing light flashes, there is spark. Set timing if engine has been apart. Timing should be close on an engine that had been running, if not maybe a problem with internal parts (timing chain or distributor). Next look into carburetor, pull throttle open and should see a squirt of gas. Gas should smell fresh if not drain tank and refill. On fuel injection I depress the bleeder valve( it should squirt gas).
4. Install spark plugs, engine should run unless there is not enough compression caused by bad valves, holes in piston, bad rings which requires compression test.
5. If motor runs adjust idle speed, check for leaks, and go for a ride.

I welcome any additions or corrections
 
moldman05, has good advice, along with transman 731! You mentioned, the fireball, & timing issues came up. Good. But could also be crossed plug wires, stuck valve, push rod, or lifter, problem.
The gas puddling, could be from flooding, or dry gaskets, on the carb. A manual choke, you would pull the butterfly closed to crank a cold motor. But in this case, I would just pour a small amount of gas down the carb throat, & give it a few seconds to vaporize in the intake. JUST to crank it, the first time! And have a fire ext., & a friend standing by! 1 thing I learned many moons ago; don't be looking into the carb, while cranking! Remember the Fireball!
 
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