DirtnastyDatty

Well I tried the other suggestions and nothing seemed to work, will swap to ngk's but i retarded the timing and the problem still persisted, installed new carb plates because the others were leaking from a crack. Regapped the plugs as they were .040 and over, cleaned the distributor, leaned out fuel idle screw and that seemed to help, but I'll try higher octane as well. Also, this is unrelated but when I took off my valve cover soon could access the carb bolts and noticed my timing chain is pretty loose, I know they can usually be loose and tighten up with oil pressure but it just seemed a little more loose than average, is it bad to run it that way? (When I manually mess with the crank the chain slaps on the drivers side)

Hello, so I've been trying to trouble shoot this for weeks and thought it was a vacuum leak, replaced carb spacers, problem persisted, ECT. But when the vacuum advance isn't connected, the engine runs just fine and doesn't seem like it wants to cut out in high rpms if I hold it there in neutral, when it's plugged it, it does exactly that, kinda sounds like it's running out of gas but it ain't, timing is advanced 10 degrees, done with generic timing light and scale on engine. Is it okay to run without vacuum advance? And any possible solutions? Thanks

I live in snohomish wa, but I can pay for shipping if necessary, need one for a 4 speed swap im doing replacing my jatco 3 speed, thanks

One more thing, it was backfiring out the carb when it was backfiring, shot out bits of the filter and everything so could that have messed up some stuff internally?

Also, does the coil need to be grounded to the chassis well? Or just to the distributor

The vacuum advance is set up, there's just that nub that looks like it could be for a ground sticming off of it, and I do have a timing light, it's set at about 9 degrees advance at idle, it ran fine for about 2 weeks after I put in the new ignition but after that is when it started acting up at mid rpms under no load. Plugs are new-ish, only a few hundred miles on them and they look healthy, valve lash though, quick rundown on what that exactly is? Heard the term but hearing it again would definitely help freshen my knowledge

Fuel filter looks fine to me, and the carb is only a few months old but it could still be the issue, I know my first few months of driving my timing was off and for a week it was so retarded it would backfire after letting off the gas every time at 50mph, so that could've messed up the carb? But I'll check everything else, looks like there's a little nub to put a fast on for a ground on the new distributors vacuum advance and it's not hooked up. I do need new rings as there are traces of oil on my spark plugs but I didn't think that would cause this issue at a certain rpm only under no load, has been a while since I checked the plugs but I'll go through the checklist and let you guys know

So I noticed this about a few weeks ago and still runs fine but around mid rpms or so, it seems like it wants to cut out, idles just fine, and high rpms are usually okay and under load it doesn't do it, but as soon as it's under no load it almost sounds like it's running out of fuel. I'm not good at diagnosing things like this, the carb I'm running is a weber 32/36 and I have a pertronix electronic ignition system. Anything helps, thanks

Wow, good to know, once again can't thank you enough for the info

I feel honored having Datzenmike reply haha, but thanks for the info guys, been afraid of blowing up the l16 going past 60, engines in good shape, just leaks a little bit of everything but I keep a jug of everything in the bed. Once again, thanks for the info

So I daily my 620 and i spend a lot of time on the freeway, it being a 3 speed, the rpms are pretty high and I don't have a tach but just going by the sound of the engine (sounds like 4500 or so), I don't want to go faster than 60. The point of this discussion is to ask if anyone knows the ratios of a Jatco 3n71b, but any other info is greatly appreciated. I've been driving/tinkering with my 620 for the past 2 years but I'm only 18 so I'm still working on my knowledge of vehicles in general. Once again, any advise/info is greatly appreciated, thanks