vacuum problem

Since been driving a motorcycle for a while been not putting much attention in my car so started it up nice and easy waited til it was warmed up, then pulled the tube from the vaccum advance from first the carb not a thing, then pulled from the distributor, no change in RPM.

The tube I am using is pretty long and thick I might change to one that is thinner and can have a more natural tight seal but if its not the case, could this explain for my lousy MPG at higher speeds?? Am I needing a new distributor now or something?

My vacuum gauge reades 1 higher at low RPM and 1 lower at high RPM but everything is steady and true no burbs or fluxuations.

If you have the stock carb and LOD distrib there is no vac. at idel.

Well, if you are at idle the vacuum port on the carb will not operate.

It is possible that your vacuum canister on the dizzy is junk. Easy way to test is to get a small vacuum pump (mitivac handheld or something like that) and while at idle, apply a vacuum to both ports (one at a time) on the dizzy and see if the timing advances at all. If not the vacuum canister needs to be replaced.

I suppose thats correct the distributor is about 10 years old minus the points since over a year ago I installed pertronix which was an instant success once I got the sleeve problem fixed.

any recommended steps on swapping out the vacuum advance diaphram on my distributor because I really dont want to swap out the distributor last time I did that I was over a tooth off and messed my life up badly, spend over 140 dollars getting mechanics to reinstall it.

Quick test for the vac cannister. disconned the vac line at the carb and plug it off. Suck on the end of the vac line while connected to the distributor and see if it holds vac. If you still have a steel vacuum line, you might need to add a hose to be able to do this. Also check to see if the steel line fittings are not leaking. Rig up the vac line to the distributor where you can safely suck on it while the engine is running. When you apply vaccuum the spark timing should advance & the engine speed should increase. If none of this works, then your cannister or the advance mechanism needs / replacement or repair. It has been years since I have looked at the Load-o-Matic distributor, but I think the vac cannister can be removed with the distributor in place.
Doug

well this is what I have done. Since I have a rubber vacuum line going to the carb from the distributor and it does not have any leaks or cracks I put a vacuum gauge on that line and its holding about 1-1.5 in Hg. When I connect the gauge to the distributor and apply vacuum it can hold pressure its not super strong it does go down abit depending how much suction you apply. But it really does not increase in RPM it surges abit above 7 in Hg but steadies above 10+ but still does not increase the RPM. When I apply a timing light after plugging the vacuum line to the carb I am not getting a timing it moves in a counterclockwise motion very steady and slow and doesnt change with increase of RPM. The RPM is about 1000 at idle but I cannot get it to lower without almost stalling it because the fuel mixture is the only way to lower the rpm, idle screw will only increase not decrease.

Have you leaned out the idle?

Check your manifold vacuum at the bung on the log. It should be 18 or over and hold fairly steady at idle.Turn the fuel/air mixer screw clockwise until the engine starts to stumble and then back it out until it hits peak vacuum - but at least 18. Then give it another quarter turn. That should be lean enough to turn the idle screw down below 1000 rpm. Otherwise, why can't you get the idle down to around 750? Maybe the cold idle cam is not pulled off.

What is the timing set at?

I have a vacuum gauge also built inside my interior and at about 1000 rpm my vacuum is around 20. I am unable to see what the timing is because when I put the timing light to the timing marks the mark moves in a circle slowly counterclockwise.

well went out to try it again, managed to lower the rpm to 650-700 car was not too happy but managed to have very steady idle and 18-19 vacuum. Timing mark moved slower counterclockwise but still cant tell what the timing is set at. if its more than 14 btdc would the timing mark go backwards like that?

Make sure when you set the timing you unplug the vacuum from the dizzy and plug the vacuum line. It shouldn't move when you do this.

I'm not sure what you mean... counterclockwise...

the vacuum can be changed by how lean or rich the carb is... try that to fine tune that vacuum, sounds like your almost there

when you check the timing you should see a mark on the balancer for the pulley but that marker is moving slowly in a counterclockwise motion instead of staying in one position. just think of a clock with the second hand representing the timing mark illuminated by the timing light but going backwards.

Slipping harmonic balancer. She's busted, I think.
Get a rebuilt from Classic Inlines.

Jackfish may be on to something. I have seen timing mark jump around when you are setting timing, but I have not seen it rotate around. A balancer might explain that. It would also explain the poor running if you set the timing by using a timing mark that has moved.
Doug

havoline, am I remebering correctly that you once had a problem with pertronix...it's possible one of the magnets/components is floating around/loose. Also, could be a missing or broken return spring on the breaker plate not keeping advance in check...or slipping balancer as suggested.
Good luck!

It also sounds like the vacuum advance can has a leak since you say it bleeds off. If you are able to hook up the vacuum pump to it and increase the vacuum while you are shooting the timing light then you should see the timing advance. With some additional rubber hose, it should be possible.
Doug

Well I may be late to the party but here goes…
I’m not sure what car you have but if your distributor looks like mine. You are good to go. Mine is a D shaft and yours could be a C.

NOTE: I put a Pertronix on my 47 Ford FH Straight 6. One day the green tape went to green tape heaven and the car ran like crapola. Up side, Pertronix sent me a new one no questions asked and no cost to me at all.

I agree with others here the vacuum-can may be kaput.. you should have increase timing when you rev the engine. (timing moves ccw) Any other vacuum leak elsewhere would cause sever idle issues.

Just to recap what other members have stated:
First confirm initial timing:
1: Disconnect vacuum line (#1) and PLUG IT.
2: Start engine and at idle look to see what your initial timing is:
(idle rpm and initial timing others here will have to tell you. cuz I ant sure)
3: Adjust if necessary:
4: Reconnect vacuum line (#1) and rev engine: Any rpm around 1000 will advance your timing. ( moving ccw)

If your timing don’t do nuffen then ya vacuum-can in defective..
It ant all that difficult.
1: Disconnect vacuum line #1
2: Remove distributor cap: & your pertronix:
3: Remove the carter pin at #3. A pin with a magnet on one end is helpful.
4: Remove the two screw #2
5: Push the canister arm down at #3 and pull the useless thing out.

Replace with new: hook up vacuum line. I don’t think I forgot anything..