1969 F100 390 wont start

[cjroddam]

i found a 69 f100 lwb with a 390 and c6 trans 2bbl...the guy before me told me the motor ran but the carb kept flooding out the motor...i bought a repair kit and did the carb...come to find out old gas had the float sticking to the bottom of the bowl...now with that problem outta the way...i have checked all plugs, firing order, timing, made sure i was getting spark, new starter, and a new battery...the motor will turn over ok on a full charge but after a few mins it starts slowing down...i have good fuel to the carb from the tank plus ive been dumping a little in the carb now and then...while pumping the heck outta the gas pedal and turning it over it will almost kick off and start seconds after i dump a little gas into the carb...it will not kick off though and even idle just rough and slow for a second...when it does try it spins just a little faster than the starter and as soon as i let off the starter it dies...has good compression on all cylinders, plugs look good, oil is normal and clean...ive been doing this for days, bumping the timing up and down a little with no change or luck...im lost, please help me

[fordman]

have you flooded it by dumping too much gas down the carb and it not igniting? it may be running on old gas from the tank. and its no good. it could be that it just needs to get gas into the fuel bowl. is the fuel pump doing its job and filling the fuel bowl? if you are saying that you rebuld the whole carb how did you set your screws for the fuel mixture? 1 1/2 turns is the standard to get it started the first time. one other thing i can think of is the timing chain might be gone in it. have you checked for that? to do that you remove the dist cap and try and start the truck. if the rotor moves then the chain is still working. but that doesnt mean tha it is still in time correctly.

[michael69]

Sounds like the timing chain since you said it was spinning faster than the starter.

[cjroddam]

yea the rotor does spin like normal so the chain is good...no i mean by spinning faster than the starter is that is will almost try to kick off and run when i dump gas down the carb...it will spin faster and try to start when gas dumped down...oh and yea the fuel bowl is filling up properly...originally the float was stuck do to old gas and junk in it but i cleaned it good and now it floats normal...and i cleaned the fuel tank out and put fresh gas in it but the tank was actually really clean no rust...plus also i have set the timing correctly

[NM5K]

Could be a timing problem, but I'd make sure the plugs aren't fuel fouled..

[convincor]

have you filed/cleaned the points?
Is there spark? Pull a plug wire off the plug and slide the boot up to expose the clip. Hold it about 1/2" from the engine and crank. Good brite blue spark?? or more orange in color?

[NM5K]

Too small a gap could do that too. Sometimes the points will slip and you will
lose the gap. That could cause a no start, but would belch a bit at times.

[cjroddam]

yea i will check the plugs tomm...i did check the spark from the coil and a plug wire and its a orange/yellow color

[cjroddam]

aight here's whats happened...oh btw the truck has been sitting for 5yrs and tinkered with every 6 months or so...but today i did wires, coil, plugs, new starter, battery cables and a holley 600 4bbl carb...truck now will start, run, and idle rough...about 2k rpms the carb keeps popping or backfiring out of it and wont rev much more than that...while doing this i was playing with the dist and timing to see if it would help but no luck really...i hear lifters tapping so imma pull the valve covers tomm and see whats up...oh, does this motor have mech or hyd lifters?

[fordman]

probably non adjustable ones. pour some marvel mystery oil in it andlet the enigne run with that in it. that will help clean and pump up the lifters. you might have slack in your timing chain.

[marine6212]

When you pull the Valve Covers look at the PUSH RODS make sure thay aren't bent!! My 390 was doing the same thing and 8 of the 16 push rods were bent 3-4 90 degrees. I will be getting my heads back next week hopefully.


Semperfi,
Marine6212

[cjroddam]

yea thats what imma check tomm...im sure the chain is loose maybe even the original...mainly i want to see now if i can make it stop tapping if so i will start doing chain, water pump, intake, etc

[cjroddam]

i was also wondering if it does have mech lifters, can i just pop in some hydr lifters or is there more to it than that?

[NM5K]

The lifters are hyd I would think. But I wouldn't mess with those yet. I'd let the marvel oil
or whatever try to free them up first. Probably just stuck from varnish or whatever, or some
are out of adjustment. Hard to say until you check them with the covers off. If any are lose
and clacking, make sure the pushrod isn't bent. If any are bent, you can get those at most
any auto parts. One note. I'm not sure if this applies to the 390, but some engines used
varied length pushrods as far as the adjustment.
Does that truck have points? I'd replace those of it does. Then I'd set the dwell to the
normal factory specs, and ditto for the timing. Then go from there if it still runs bad.
But you need to make sure the dwell and timing are right before you can go much
farther. "You mentioned it pops" That can be timing..
You might need a carb rebuild before it's over. I bet it's got varnish crud in it.
Also, make sure no varnish is in the gas tank. That can cause all kinds of grief
including causing valves to stick so hard when cold that it bends pushrods.
I had this happen on my 300 when I first got the truck. Had lots of varnish in the
tank at first. I'd get it running pretty good, and come back the next morning and
start it up, and have valves stick. I had a couple of bent pushrods, and on one or
two, it would force the rocker mounting stud up to the point it would all come loose
and I'd lose that valve.. Clack city.. Varnish is like hard glue when it's cold.
If you see or smell signs of varnish when it's running, I'd yank the tank and clean
it out.

[cjroddam]

timing is set right...points are new...i got it running with the new carb on it...pulled the valve covers and one head looked good...the other LOL was f**ked...2 missing pushrods, and the valve train shaft is broken on the last bolt that bolts it to the head so the last 3 rockers were just laying there, 2 missing rods, and one rod just sitting on the lifter and not attached to the rocker arm cuz its broken...so i need some heads or get these redone...this is why the popping in the carb and when i adjusted the timing while running it would not affect it till i turned the dist so much it died...so i got to tear it down to the block