Setting carb and timing?

[CABBOTT]

Anyone here have the proper procedure for setting a carb and timing? I just finished the team rush upgrade on the ignition for my AMC 360, however I have to keep at higher rpms to keep from dying. I would like to be able to idle as low as possible. Thanks in advance everyone

 

[Jimbos76cj]

Google how to set your timing with a vacuum gauge. Also make sure you have no vacuum leaks. By setting it with the vacuum gauge that will help get the carb right and the timing set.

 

[thescot]

The timing is a mechanical setting if you will,unplug the advance and try to get it as close to factory spec while running near idle speeds otherwise the mechanical advance starts to kick in. After its all set up many guys say advance till it pings under load and then retard a few degrees. A general rule on carb mix screws is 2.5 out to start and go from there. The carb setting can then be done with a vacuum gauge and then screwed in till it starts to noticeably drop in rpm and stumble, then back out 1/4 to 1/2 or so till its smooth again. If your having to run anything more than 750rpm at idle to keep things running there's something else going on IMO. Vac leak,bad base gasket, or??

 

[1986cj7]

The timing is a mechanical setting if you will,unplug the advance and try to get it as close to factory spec while running near idle speeds otherwise the mechanical advance starts to kick in. After its all set up many guys say advance till it pings under load and then retard a few degrees. A general rule on carb mix screws is 2.5 out to start and go from there. The carb setting can then be done with a vacuum gauge and then screwed in till it starts to noticeably drop in rpm and stumble, then back out 1/4 to 1/2 or so till its smooth again. If your having to run anything more than 750rpm at idle to keep things running there's something else going on IMO. Vac leak,bad base gasket, or??

x2 even though I have only done my AMC 258 i6 / 4.2l but should be the same. This is the same I did when I rebuild my Carter bbd.

 

[CABBOTT]

Awesome thanks guys

 

[Bear991]

Not to highjack the thread but my CJ with a AMC 304 automatic 2V carb wants to stumble under acceleration at times. Hot or cold doesn't seem to matter. I've check and rechecked the timing and vacuum advance put a new rotor button in just for the heck of it and new plugs gaped to specs. no change. Set the carb by Motorcraft specs with a vacuum gauge,no change. Could this be a power valve issue in the carb?

 

[thescot]

Kinda forgot one major item..the idle speed screw on the carb itself. Cant imagine just doing a TR change affected anything but the timing if you moved the distributor. If the cap adapter sets the cap in the identical spot it was then it shouldnt have changed anything by much.Still a must to recheck the timing though to make sure.

 

[CABBOTT]

Well I didn't work on the jeep today, nut when I finished the ignition, I rechecked timing multiple times. So knowing I needed to come here and ask proper protocol I got the engine warm, ran the mixture screws in all the way backed out a full turn and half, plugged all vacuum lines but left the distributer vac. advance connected. Then I had to idle the engine up ( not sure what rpm, don't have my tach wired up yet) till running smooth and set the timing at zero. I know is was not the proper procedure. But that's where I called it a night
Ok for a little info, it's an AMC 360, team rush upgrade, has edelbock performer intake manifold and edelbock carb. Any pics you guys might have of vac lines for the carb and preferred step by step procedure on setting up would greatly be appreciated I know I'm being lazy but it's been a hard couple weeks for me, and been putting a lot of time in the jeep, just want to hear it running right and start off the bat

 

[Bear991]

When I said I set the carb to Motorcraft specs that included the idle speed screw

 

[Hedgehog]

CABBOTT - Did this engine run properly before the modification? The timing seems fairly straight forward, because close does count on initial start-up. That leaves the carb.

I seem to remember that you just dropped the 360 in. If the carb. sat a while with gas in the bowl the low speed jets are probably gunked up. The carb might need a rebuild focused on the jets to run properly.

Went back and looked at your older threads. It looks like your doing a LOT of work on your Jeep and it hasn't run in a while. I'd go with a carb. rebuild.

 

[CABBOTT]

Yeah it's been sitting for some time now, it did run good before I started the project. I think your right ill focus on the carb, I know the timing side is good but I figured I needed the carb worked on to make it right. I hate working on carbs

 

[DHugg]

Not to highjack the thread but my CJ with a AMC 304 automatic 2V carb wants to stumble under acceleration at times. Hot or cold doesn't seem to matter. I've check and rechecked the timing and vacuum advance put a new rotor button in just for the heck of it and new plugs gaped to specs. no change. Set the carb by Motorcraft specs with a vacuum gauge,no change. Could this be a power valve issue in the carb?

Same engine, tranny, & MC2100 in my '80 - no pollution controls - and she stumbles a bit at liftoff. Reading a bunch of stuff on MC2100 says the power valve actuator should squirt some fuel just before the throttle butterfly opens, an adjustment issue. Also says that if there have been some serious backfires, the power valve diaphragm may be ripped.

I gotta rebuild the carb, so the power valve diaphragm is on my punch list.

 

[DHugg]

Same engine, tranny, & MC2100 in my '80 - no pollution controls - and she stumbles a bit at liftoff. Reading a bunch of stuff on MC2100 says the power valve actuator should squirt some fuel just before the throttle butterfly opens, an adjustment issue. Also says that if there have been some serious backfires, the power valve diaphragm may be ripped.

I gotta rebuild the carb, so the power valve diaphragm is on my punch list.

THE SEQUEL

I DID rebuild the carb....... found one of the screws in the accelerator pump cover was too long, and the last gorilla that assembled it punched the screw through the aluminum sidewall of the float bowl. Aluminum slag was fouling the needle seat every time the Jeep turned a corner. The remedy... new carb.

Put the new carb on, set it up without dinking around with the timing, and she's got a bad, bad off-idle stumble. Sometimes dies on acceleration when cold (what passes for cold here in this climate). Cutting to the chase, put my new Craftsman timing light on it w/o distributor vacuum line, and found the initial timing set at 16 degrees. Dialed the timing back to 10 degrees and the stumble is almost imperceptible. 8 degrees should be spot-on.