Mitchell

Yes we do and ethanol free at the pump as well. I agree and backed it off by ear a degree or 2, have to say my truck is running the best ever, smooth and feels like 2 or 3 hp increase, Now onto that nasty leaky front main seal...

Thanks, still enjoying the moment it started right away and that it ran perfect immediately! I haven't fine tuned the weber yet, I just matched the number of turns on the jet with my old one, might not need to do anything except lean out the main a bit while driving it around, so don't worry about another 4 pages yet! The old distributor hasn't been rebuilt yet, so unfortunately don't know exactly what's wrong with it until I send it in to be rebuilt, but I'll make sure to let you know once I find out. The recycled one I just bought last month, is the one that was sent off to be rebuilt and is now running on my truck. Before I sent it out I had tried it and it wouldn't even run, a couple of pops that's it, but that was before the new carb (new accelerator pump/new clean inlet tubes). He said the magnet ring had cracks in it, he included the broken magnet ring pieces in a bag with it. He also included a note to set the timing at 14-16 btdc. Talked to him this morning and he really knows his stuff, he's a member here on Ratsun aka DistributorGuy he actually was able to run his 620 truck to 141 mph at the flats...

Finally SOLVED!!! Here are the timing photos at 0 degrees... Crankshaft Pulley Position >>> Camshaft Timing Gear Alignment Position >>> Camshaft 10 and 2 Position >>> Distributor Drive Position >>> Distributor Rotor Position >>> So after checking the timing, had the same result with the original distributor having a low rev maximum. So I went ahead and installed the newly rebuilt distributor I received today from Jeff at Advanced Distributors and It started right up and NOW runs better than before all this occurred on April 13th. Timing is now at 15 degrees BTDC. So apparently a weak accelerator pump combined with a faulty distributor were the causes. Thanks to all who helped solve both of these problems!

Thanks Mike, just getting started going through it and first setting it at 0, also received the rebuilt distributor from Jeff today... I will post the timing pictures later on.

Thank you all for replying. This is the original distributor and pedestal that is just like the 3rd one on the right in the photo that came with the truck and has over 100 thousand miles that I've put on it. I've never changed the pedestal. I did send another L20b matchbox of unknown condition to be rebuilt by Jeff at Advanced. I bought it from AbcUsedParts Recyclers but did not receive the pedestal with it though. The accelerator pump does work with the new carb. The photo of the Cam is with both the intake and exhaust cams in the up position as shown more clearly in wayno's photo, at 10 and 2. I use a starter trigger button on the starter to position the crank pulley and so it only turns the crank clockwise and when I overshoot I just go around twice to get it right. I'll take another set of pics with the crank pulley exactly on 0. This is a closeup of where the crank pulley was...

Here are the timing verification photos, It runs, starts easily but won't rev still. Checking with a timing light, While idling at 750 rpm, I don't have enough adjustment on the distributor to advance the timing it's limited to about 5 degrees ATDC with the the plate bolt loosened and clocked all the way. Before I drop the pump, would changing the cam pulley to position number 1 or 3 help? I removed the distributor bolt and temporarily clamped the base to gain a little more advance but still not enough but does improve a little. I also tried clocking the wires both directions, still not enough adjustment. Cam looks correct, at 10 degrees static timing, pulley aligns with 2 on mark with both valves closed...? Distributor drive looks correct, small side left at 11:25...? Timing Mark on pulley at about 10 degrees, photo is a little blurred but mark is in silver paint area about in the middle...? Distributor Rotor facing rearward on number 1...

Thanks Mike, Just getting a little short on patience today, tomorrow will make a month since this all began and have spent over a thousand dollars without exaggeration. I'll get back on it tomorrow, What happened was I got careless with having the timing light, the starter trigger and a battery charger on at the same time and saw some sparks a that was it for today... fusible link and fuses are all okay but the starter not

Thanks for all of your efforts, I'm frustrated with it as I think I shorted out the starter today accidentally...

Thanks for that, I'll check for both being closed. Jeff at Advanced Distributors said he sees them come in with a crack sometimes in the magnet, so maybe as a guess, the centrifugal force at about 2500 could cause the no spark or spark scatter occurs, he also mentioned a ball bearing can disintegrate or fall out that supports the plate. I've got over a 100k miles on this distributor. To me the shaft felt like it has some play I can feel when pushing on it side to side.

Tomorrow morning I plan on checking the compression, timing and valve lash hot tomorrow, just finished raining here with over 3 inches. I did place a wood dowel in number 1 earlier this morning at TDC and it was in the up compression position, I also verified 11:25 (wide side left) on the distributor drive but I didn't have the valve cover off. I have read about distributor shaft wobble causing an ignition wall, hoping that's what it is... but what I read said it occurs at a higher rpm. As mentioned I have a spare distributor being rebuilt. Can a distributor be assembled 180 degrees out and would that cause any issues? I can verify the new carb accelerator pump squirts fuel. I have also swapped brand new flamethrower II 0.6 ohm coil as well as a new NGK 1.2 ohm coil both work verified with a multi-meter and the 0.6 runs slightly better. So maybe some spark scatter? The original Diamond coil is reading a little off on the secondary and primary measurements. So recapping; Coil, Cap, Rotor, Wires and Plugs are all new. Swapped 4 different ignitors 2 were new aftermarket 2 are E12-80 oem used.

or maybe one of the internal emulsion tubes is partially clogged. Since the new carb is doing about the same thing it must be something else... Maybe too much distributor shaft play, causing higher rpm arc? or burnt valves? It started pouring down rain here, I'm going to do a warm compression check and check valve lash hot this time, check timing again and see where those are at...

Thanks very much, Carb came with a new gasket. I will check each item you've mentioned, it just started raining so it will be a little while. I had checked valve lash last week cold and found only number 4 exhaust was too tight. At least now I can check them hot...

New carb installed easily and it started right up runs a noticeably smoother, revs a little bit higher to 2500 (from 2100) and idles smoother, but not revving beyond that without popping. My timing is verified good, the truck starts very good. I'm back to looking at the distributor possibly not advancing or shorting internally? I have sent my recycled unknown matchbox distributor to Jeff at advanced distributors to be rebuilt with good parts, but it will be another week before I get it back...

Thanks Mike, I'll be putting the new identical 32/36 carb on tomorrow morning, should be interesting...

I ran it again today and was able to drive it to my home, of course slowly under 2100 rpm. So now the truck is on a concrete driveway and within reach of air tools and electricity. I verified while it was running and immediately after shutting it off, that it will not squirt fuel. I also checked my plugs and they looked like it is running very lean, white in color, but they are new set of plugs... The new carb just arrived, so that's why I thought about doing it with the carb out of the truck since It would just be much easier to access the 4 screws, but doable if necessary while on the manifold. I would like to know if the diaphragm is cracked or torn so if it matters, I'll take the accelerator pump before removing the carb. So, does it matter if I check the accelerator pump after taking the carb out? Thanks