Fambugee

Hey guys so I'm timing my '86 22r and noticed that the timing doesn't change when disconnecting the vacuum lines to the dizzy. '85 FSM says it should be 12 connected and 0 disconnected. I figure my vacuum advance is broken. So, I sucked on both vacuum lines and the one towards the front held vacuum and the inboard one i was able to slowly suck air through. Is this right? What's even stranger is I swapped the vacuum lines to the dizzy and this caused timing to work perfectly. 12 with lines connected and 0 with them disconnected. This is with them connected IMPROPERLY according to the diagram. With it configured like this, when i rev the motor the timing instantly drops to 0 and then advances the more I rev. So, what's goin' on here somebody set me straight I'm a newbie with carbed motor thanks!!

Fambugee

man over a hundred views with no carb gurus? bummer. surely someone is schooled up on this advance system. suppose it's due replacement just trying to learn how it works............i've researched it to death but i need more knowledge!

stock87

Well, first of all it's really common for the diaphragm to be blown after this many years, I know mine was. When I replaced mine, the dealer was actually the cheapest source for the part, a little over a hundred bucks a few years back.

Both ports advance the timing, as you discovered, but it's a question of when. The timing is supposed to advance at idle, then drop to zero and slowly advance via the weights as you rev it up. I can't remember what the second port was for right now, if I get a chance I'll check the FSM. It's been a few years since I messed with any of that stuff.

Fambugee

thanks for the info. i messed with it a little today and noticed that the outboard one which is holding vacuum will advance the timing AFTER the truck is warmed up and off the fast idle cam. so i'm assuming the inboard one that is busted on mine does something when the truck is cold/warming up. then again, this is with the vacuum lines swapped so perhaps this is a moot point. i'm gonna just get a new distributor i think since they are only slightly more expensive than the advance unit itself.

nightstalker

its cheaper to buy the whole dist. than just the vac adv. you will get sticker shock from just the vac adv price!

Fambugee

turned out to be the advance on my distributor AND a cracked hard vacuum line for the advance. got a new distributor and just ran a soft vacuum line from one end to the other...............all is well now and she works like she should now.