Duraspark complete, truck dies after a few minutes

[jaredm_k]

I took the top off the carb while on level and my float was actually a little low. But I got it set right at 3/4" now. Fuel is not dripping out of the accelerator pump or the power valve that I can tell. I am attaching a couple of pictures. The one with my finger in it is pointing right to where I saw the fuel seeping. It was above the spacer on the front right corner of the carb. Because I was adjusting the float level - I did get some gas splashing out of the carb tonight so I was unable to see if it was happening tonight.

I wasn't sure which short hose to the manifold you were talking about....but the one that is beneath the carb (that I have plugged) did not have fuel in it when I pulled it off. You can see the plugged hose I am talking about in one of the pictures.

I appreciate your help - I'm trying to be descriptive as possible when explaining what is going on, but let me know if something doesn't make sense or I am not explaining it clear enough. Thanks!

 

[kimcrwbr1]

That carb has the internal port for the power valve. The nipple you have plugged would normally go to the cover for the power valve. Fuel dripping out the spacer does not make sense. maybe get a small screwdriver bit and loosen the screws for the power valve cover and see if there is fuel there. If so you may need a new power valve or the gasket is leaking allowing the fuel to drain out of the float bowl? I had the gasket split once for the power valve with a similar issue. A slow drip made it real hard to start unless I put the pedal to the floor.

 

[kimcrwbr1]

The way the power valve works is high vacuum pressure closes the power valve and it runs on the fuel jets when you put the pedal down and vacuum drops it opens the power valve and it increases the amount of fuel going to the venturi booster.

 

[kimcrwbr1]

Its been a while since that happened if you can turn the slow needles in and the motor dont respond properly it is probably fuel leaking past the power valve.

 

[kimcrwbr1]

BTW that hose next to the drivers side idle air needle is the one you want to use for the vacuum advance on the distributer. I was talking about the nipple on the egr spacer under the carb. Just plug the vacuum port on the passenger side base of the carb

 

[jaredm_k]

Thanks - I took the cover off the power valve tonight and it was dry....no evidence of fuel getting by the power valve. That was the only thing I was able to check tonight as I got home later than normal. The gasket looks good as well.

When it is running, if I turn the needles in too far, it will kill the motor. So it definitely responds to it.

That's all the news I have tonight. Hopefully I can work on it more this weekend and provide some more clues. As always, I appreciate the response.

Jared

 

[kimcrwbr1]

The only other thing I can think of is the screw for the venturi cluster being loose or a leaky gasket. Does the accelerator pump work good? Look down the center of the carb and pump the throttle once. You should get a nice steady stream of fuel out of both of the accleerator nozzles. I believe the gasket for the venturi cluster is below the level of the fuel in the float bowl and could be another possibility. Was the drivers side down hill when you had it parked on the hill?

 

[jaredm_k]

The accelerator pump works well. I will pull the top off and check the venturi screw/gasket next time I can get out there. Maybe tomorrow night before I can get to it.

The drivers side was down the hill when it was parked.

 

[jaredm_k]

Well I went ahead and got another carb this weekend. Had it running for a long time when it died while I was trying to tune it. I left it sit as I had to run out for a few minutes and when I got back to it....it was crank and no start. I pulled a wire and put a spare spark plug in there and had my wife turn it over. No spark. Used my test light and with the key ON I had power to the coil. So I guess I will be buying a coil. Man I just want this thing back on the road!!

 

[frankp05]

Did you follow the write up in the tech articles? I just did mine and I changed from the TFI Coil to the canister style and I think I need to add a ballast resistor. I cranked mine over a few times to try and get it to start and in just doing that my coil got super hot!! I wired and used all the parts from the write up to the "T"... How did you wire the TFI? Thinking about switching back to that coil too see if it gets hot like the other one did. Im thinking I can just leave the wiring the way it is and just tap the TFI coil into red and green wire that I already modified to Tech Articles instruction but im not sure.

 

[kimcrwbr1]

I have been running on the stock square coil for 5 years now with zero issues!!

 

[jaredm_k]

I also used the stock TFI coil. I followed the tech article, I spliced the red and light green into the positive side of the coil. If you get a ballast resistor I am sure that would help your problem, or just throw the stock coil back in there. I actually had mine running the other day for probably 30 minutes when suddenly gas shot out of the top of the carburetor and when I shut it off, the ignition box was smoking.

I thought I had this thing in time, but now I am questioning if my timing marks are correct and if what I think is TDC is the correct line on the balancer. This weekend I plan to pull the number 1 plug and bump it to TDC to confirm I have the correct timing mark. Can't get anything done in the evenings as it is dark now when I get home and the bronco is outside. Anyway, progress is slow but crossing my fingers I can get this thing back on the road asap.

 

[GKM007]

I had a heck of a time with my timing (which ended up being a pointing at 10) When I found TDC the mark I was sitting on was the thick notch mark at the beginning of the numbers.

I ended up finding TDC by sticking a chop stick down the spark plug hole and turning the alternator pulley, then pulled my dizzy out and pointed the rotor just past 12 and when it seated down it was dead nuts at 11. Connected everything back up and stuck a timing light on it with the dizzy connect to vac and was sitting around 12, so I was pretty close.

 

[frankp05]

Quick question Jared did you cut the red/lt green Hot when key on wire after the plug and wire it to the coil? Kim I read you used a harness from an 84 to wire yours up so im not sure if you had to do this. I haven't pulled all of the harness out yet or the computer all I did was just tap into the red/ lt green wire after the plug and added a jump wire to the coil from the red/ lt green wire like the write up describes. But now that im looking at the diagram again im thinking I need to cut the red/lt green wire after the plug so its not connected to the computer anymore. Could this be causing my coil to get hot because its getting hot with out even cranking the motor I mean its getting hot just being wired up with the key on. Oh yeah I went back to the TFI coil today and I had no spark and was also getting hot so im guessing this could be my problem. Will troubleshoot my coil tomorrow make sure its working.

 

[kimcrwbr1]

Mine is a 83 so the red and white wires were plug and play the colors are reversed. all I had to do was splice in the green wire and she fired right up. My distributor harness was out of a 84 2.0. For the red and white wire on a 85 model just wire hot for the coil to the red on the module and for the white wire you can run a wire from the start solenoid hot only in start. The white wire retards the timing electronically and not really necessary. Guys run the 4 wire hei module with no problems.