The Stovebolt Site Forums The Shop Area Engine Shop Vacuum Advance on Dizzy?

I think I'm having problems with the vacuum advance on my dizzy. Are these easy to replace and if I have to pull the dizzy out are there any attentions to detail that I have to be careful of? I've never done this before. Does the dizzy only go in one way? I'm having problems with climbing hills again because of the mountainous area I live in.

I also just replace the carb with a rebuilt Carter W1-574S that I purchased from ALFA CARBURETORS STOCK in Lynwood, CA. Don't know if that carb is giving me the issue or not. Have all new S/S fuel lines from the tank to pump and then to carb.

I'm having serious trouble with the timing all of a sudden and am wondering if its the vacuum advance not functioning correctly at the distributor.

What does it sound like to you folks?

I'm very annoyed at the moment!

What steps have you taken to determine it is an issue with the timing?

The main function of the vacuum advance is to advance the timing while you are cruising down the road while not under load (think going down the freeway on the flat). This is to boost fuel economy. When you are going up a hill, you have your foot in the throttle and almost no vacuum to the advance on the dizzy so, that should not be affecting your hill climbing abilities.

You also have initial timing and the mechanical advance in the dizzy itself.

69Cuda got it - the advance mechanism should shut down automatically under load.

I agree the vacuum advance is basically for fuel mileage at part throttle driving. Check your point gap & the initial timing. You can set the initial timing a little higher than specks as the gas we get know has more octane then back when these were new. You didn't say what engine you are running. Does the carb you put on have the same dia. throat or larger then the original?
If it is smaller it will reduce the power.
I take it this is a Stovebolt 6 engine. You can tell if the vacuum advance is working by watching it as you accelerate the engine. If you open the throttle a little the dist should turn a little. If the engine bogs when you accelerate after it is warmed up, the carb may be a little lean. If it blows black smoke or leaves black soot on the inside of the spark plugs it is running too rich.
George

Did you have hill climbing problems before changing the carb? If not, there is your problem. Vacuum advance is easy to test with a timing light.

I have played with the timing all day today. The distributor is suppose to be set at 5 degrees above center. That I have. She fires up OK but when I apply power the engine starts missing and at times just stops. The choke is wide open. At idle I can hear the missing of the engine at the tail pipe. I haven't put a timing light on her yet. I've been trying to do the adjustment by ear. Its a simple machine and I just don't understand why all of a sudden I've got this issue.

I had a Carter YF carb on her last year and she was running fine. I switched her carb out for a historically correct one (the W1) just because I want to make her as original as possible. Its just my thing. Anyway its driving me crazy why she turned so bad on me. Loose woman?

The engine, for its age has plenty of power, but something has happened after I switched carbs. Looking for advice as to what I'm over looking.

Oh, the other day a friend of mine helped me replace the fuel line from the tank to the pump with a S/S one. We also emptied the gas tank and got rid of the ethanol gas and replaced it with premium ethanol free gas hoping we would get better performance.

The easiest test would be to put the old carburetor back on and see if the problem goes away. While you have the Carter W1-574S carb off, take a look at the gasket to see if it blocks off the small hole in the manifold. You might not have the correct carb gasket, which will cause problems.
Carl

One other observation is that I pulled all the spark plugs right after the new fuel line was installed and the plugs were "heavily laden with carbon deposits". Just another FYI. I cleaned them and gaped them to the required .040 inch.

Did they become "heavily laden with carbon deposits", from running on the old carb, or the new one?

David, I'd switch the carbs. Not that big of a job and it should answer a lot of questions.
Say hi to Pam.

Hello Alvin!

Are you saying that the Carter YF is a better carb over the Carter W1?

I swapped out the carbs last October when I found this rebuilt W1 carb thinking it would be more historically correct, however, not too sure it would function as well as the YF. I do not know or understand the exact differences between these two units. Maybe I made a mistake.

Last year when I did the swap from YF to W1, I took her out and she seemed to run fine except for missing and bucking on occasion. Then Lucille sat all winter long and I would occasionally go out and let her idle for a few minutes until warm. She had the ethanol gas in her at that time. Just the other day my friend and I ran the new S/S fuel lines and switched out the ethanol gas for ethanol free premium gas. As I think about it now the plugs were fouled at that time which I did not know. After switching out the fuel lines and gas we took her out for a run and I had a very difficult time getting her back home and climbing the hills around here in Murphy, NC. By the time I got her home she was running so rough that she finally wouldn't even idle and came to a total stop. I let her cool off a bit and was able in about a half hour to get her running enough to get her back in the garage. I then pulled her plugs and found them to be extremely fouled. Cleaned and gaped plugs to .040. Then I noticed that the manual choke valved was not in the fully open position, so I adjusted the connection.

Here is where I started scratching my head. I couldn't get her to stay fired up. Kept dying on me. Then I thought well maybe its a vacuum problem, so I tightened all the vacuum oriented connections. Even went back and tightened the carb down to the intake manifold. She then ran a bit better but rough. That's when I started monkeying around with the distributor trying to find that sweet running spot. No matter what I did she is still not running right. It seemed that she would idle OK, however once I gave her some gas she just went back to running rough again. Matter of fact I couldn't even back her out of the garage.

I feel like I'm pounding my head against a brick wall. Once I stop I know I'll feel better!!

Well that's my story and I'm sticking to it. It seems like it should be a no brainer but I'm getting weary of making stabs in the dark. I really want to see her purring again. I had her running well when I was in SC, but that was pretty flat land down there. These mountains are a challenge, however, beautiful!

Check the points gap, points, condenser, rotor, maybe a cheap fix. It's been a long time since I messed with anything but electronic ignition but I thought plug gaps on these old critters was .035. FWIW

OK, just did a little quick vacuum test on the diaphragm valve on the distributor. I just a transfer pump with a small rubber nozzle on it to fit in the valves port. The timing plate moved with a couple of pumps. Question is, what sort of maximum vacuum reading should I get? I'll have to figure out a way to attach a gauge to the transfer pump to get a reading and to see if the reading is holding. The rubber on that diaphragm could be a bit dry rotted. Gotta look at it a bit closer. I'm thinking that just a pin hole leak could effect its performance. Any thoughts?

Your vacuum advance is fine if it moved with just a couple of pumps. You should look at some other cause. After rereading all your posts I believe you have a fuel problem. Somewhere or something is partially plugged up. Check flow at the tank then at the inlet of the pump then the outlet of the pump. If all those areas are flowing freely then you probably need to open up the carb and have a look.

Just got back from my local FLAPS and we determined the vacuum valve is fine. Now next stop is looking to see what the vacuum situation is at the carb. That's for tomorrow.

I truly believe that all my fuel supply system is OK. Everything is new with S/S lines and new pump and the gas tank is very clean.

So if I don't have vacuum at the carb, then there must be a blocked port somewhere. I'll check that tomorrow. Right now its just too darn hot in the garage. I'll welcome fall any time it wants to show up!!

My bet would be a gummed up carb. I know you said you started it a few times and let it just idle which doesn't take much fuel.

...not recommending one carb over the other. I let CarbKing handle that. A good cleaning is in order.

Thing about it Alvin is that I purchased a rebuilt Carter W1 (for $275.00 from a business in CA) and I have only put 10-20 miles on it. Most of those miles were run on ethanol gas. About 6 miles on the premium ethanol free gas.

Tomorrow I'll check to see if there is a blocked carb port at the intake manifold.