OK, I've got a 51 Merc flathead with three 97's on it. Car fires up and idles perfect. Rev the engine, perfect. When you put it under load it's ****. Sputters, pops, muffled sounds. I have a low output electric fuel pump, with an inline regulator. Checked the regulator with an inline gauge to check pressure to carbs. Everything seems to be working fine. I just installed a new distributor which switched to mech. advance works great. Got it off of GMC Bubba on here. I am down to just one carb right now. The middle carb. Note that the car used to run just fine. About a week ago went for a short drive. Stopped for about an hour. Went to leave and that's when the trouble started. Does anybody have any ideas. I am looking for anything to try and solve this problem. I am out of ideas, and need some input. Help me out guys! I'm burned out!
My GUESS is one of 3 things: Carb, ignition or vacuum. Bubba's dizzy works well on my 265 engine. I doubt if it's a problem. Does your coil have an internal resistor? If you are only using the center carb why not try one of the others in it's place to eliminate the carb as being the problem. I hope that you have the other two blanked off at the base. I'd put a timing light on it and also a vacuum guage. You may have a vacuum leak. Hard to say from here.
Well, not the condenser or the coil. New ones added today. Messed with the timing a little I don't believe that's it either. I am starting to think it is carbs. Going to do a rebuild on one and see how it goes from there.
Concentrate on mainjets and tubes, idle jet, and p***ages and openings for idle and off idle in base. Likely something in one of those. Be sure air bleed holes at top of tube and their mount casting are clean too.
Try testing! Hook up a cheep vac***e gauge from Pep Boys or sears it will tell a lot right on the gauge face Valves timing whatever also a compression test> you dont need a computer and all new and old engins respond to this testing Been there don that Hope it helps
One last thing while I am waiting on my carb rebuild kit, I am going to put new plugs and plug wires on. Right now I am running the old Champion H10s, and old Ford plug wires. I don't really know how long they've been in the car. They were in it when I bought it. Just want to completely eliminate that. I am going to install some new Autolite 216's then it's on to the center carb and work my way from there. I'll keep you guys posted on the results. Hopefully they will be good.
Hope you're not using Teflon tape or sealer on your fittings. It'll wind it's way - like a tapeworm - into and around your main jets.
This one is back from the dead, but I wanted those to know that when I changed the plugs and plug wires, it was a new car. Runs better than ever before.