Barely Runs...Need Help

[Mad Joe]

86 250 Maxie with 318 & 2bbl carb. New crate engine 55k miles ago (7years ago). Carb rebuilt at same time

Had to be towed home at midnight but problem started earlier in the day. Very difficult to start and after letting it warm up, it will bog down with any load and die. Got it finally started again and this time sounded normal and would rev good. Then under a load it starts backfiring and bogs down again and dies. Finally got it running and all seemed fine as I drove it 15 miles. Parked van for 6 hours and ran into the problems again at midnight. The choke is not sticking.

Now here is what I am fearing. 24 hours ago I filled up (35 gallons) at the station across the street and pulled back home no problems. Yesterday morning it fired right up and ran as usual for less than 2 miles and the problems started. I fear watered gas. It for sure appears to be a carb problem and it may be a fluke that it started right after a fill up.

Went to the gas staion tonight and asked if there had been any reports of "bad gas", and of course they told me no. Cna't imagine they would say yes.

I'm left scratching my head. I'm not a very advanced mechanic, but I can do some basic stuff. What do you think?

As always, thanks for your time. I'm sure I will be posting more as the replies come in.

[97B2500CCV]

Simplest thing to check first is the fuel filter. When was the last time it was changed?
Second check for any bad vacuum lines, if any look bad then replace. Third is to check for spark at the plugs.

If you suspect water in the fuel and have some one whom know how to help you the you can remove the fuel line to the carburator and pull the wire going to the hot side of the coil and crank the engine for about 15 second every two minutes to help pump what ever water is in the system out. Do this until the line has only gasoline. Make sure not cause a spark while doing this.

I had a car that I did get water in the gas, fortunetly I was able just to crank and let it sputer and die then restart several times. After about 1 or 2 minutes of fighting with it the water cleared out and it ran fine. If the water is in the carb. then you may have to use carb cleaner to help get the engine to run as you clear out the water from the carb. Trying to keep the engine running as it pull the water that is left in the carb through is better than trying to remove and dump the water out of the carb. Do this only if you have purged the water from the fuel tank and lines first other wise this is a loosing battal.

[Mad Joe]

Thanks for the reply.

Update...Have just discovered I have no spark. It must be an intermttent problem. I had it yesterday. Off to buy a control module. Could the problems I have described above be caused by a bad control module?

Thanks again.

[alloro]

Could the problems I have described above be caused by a bad control module?

Yes, and it usually gets worse, the hotter the module is.

[Mad Joe]

Thank you. I will replace and report results back.

Also, I want to replace the coil. These coils mount horizontal and I seem to remember that you are suppose to have the + or - in the top postion. Is that correct and if so, which side goes on top?

Thanks again.

[97B2500CCV]

Negative is best so if something drops on it that it will not short out.

[Mad Joe]

Thanks again.

I really must be getting old. Years ago I replaced the module and I think it is on the firewall. For the love of Pete, I can't see it there now. All I see is the voltage reg and what I call the large black compurter box.

Where will I find the control module with the diode on it located?

I'm losing it in my old age.

[Mad Joe]

I'm reporting back that replaced coil and van fired right up. Is it possible the control module has an intermittent problem that would allow the coil to fire sometimes and then sometimes not?

BTW, still can't find that darn module.

Thanks again.

[97B2500CCV]

The computer box is what controls the ignition system, it would be the control module. You should beable to trace the distributor wiring back to that box. I don't have the diagrams before me but I do not believe that on your van that the computer controls the coil pack. Most likely the coil pack failed internally on its own.