Weber 38/38 DGAS question

So I'm pretty sure I'm chasing a ghost and raising my blood pressure and throwing money away for nothing. When I got home today she fired right up and gave me a good 15 min of tune time. It of course died a few time but always started back up. That's until she didn't. I've brought all the Screws back to Weber's recommended starting to tune point and nothing. So I walked away (again) and got thinking it has to be in the ignition somewhere. I checked all connections and gave her a whirl and wala she started again. Then while tuning she died again. So with a original 81 Motorcraft Duraspark and everything past that new what's the chances that the Motorcraft Duraspark is the problem. Has anyone ever had one go bad in this type of manner? as in doesn't provide full spark when into the throttle, hesitation, then just kaput until it cools down?????

Sincerely

ripping my hair out and watching the last few warm days of summer go away.

Again thanks in advance. RJ

 

I have had the exact same problem with mine. I had a bad electronic module in my HEI. I was getting spark but it was not enough. I thought I had carb problems but wasn't. My son loaned me a simple tool he has to connect the spark plug wire to so you can watch the spark jump the gap. The gap can be widened and narrowed to see how wide a gap the spark can jump. Old timers used to pull a plug wire and watch the spark jump from the wire to the plug as they moved it back and forth. Ignition wires can build resistance over time and reduce the available spark as well.

I'll try to remember to check the jet size and post back later.

 

Ok, now for the jet information.

I bought the carb used and it had #45 jets in it. Right now it is running #65 jets and it runs perfectly. I had tried #55 and #60 while experimenting with it.

If you go to buy new jets remember to buy one of each "size". One of the jets is physically larger than the other. You will probably want to keep the orifice size the same for both at least initially. When you get it running good you can tweak to your heart's delight.

Additionally, these carbs are known for having a dry float bowl after sitting for a while. It seems the funky adapter that mates the carb to a Jeep intake transfers heat too well and the fuel boils off after the engine is turned off. The factory carb had a phenolic spacer to help with this. I have tried every fix I can find on the internet for this problem, and finally installed an electric fuel pump to fill the bowl when I get ready to go somewhere. I would use the electric pump full time except it is quite loud and don't like my Jeep sounding like an airplane. I am thinking about trying a different electric pump, but I have thrown so much money at this problem I am about ready to go the Ford carb route. I had initially purchased this particular pump because it operates in the pressure range of the carb and I would not need the fuel pressure regulator. But alas, I am picky about noise.


Good luck,
Jim

 

Well I got it figured out it's amazing how if throw enough money at something it will some how get fixed. long story short the 9 month old Accel coil went bad AGAIN!!!!!! it was sparking but just not enough I guess. I said screw it and spent $35 just to see what would happen and wala it runs great. NOW the fun problem is that damn fuel pump..... Go look at my next post... Thanks everyone who chimed in to help I really appreciate it.

OH and my Jet sizes are
145 Main
170 Air
45 Idle
70 pump
200 needle seat