78 Midget - fuel issue or distributor?? HELP!

[lbc_newbie]

I finally got the stinking rebuild kit for my carb today (after waiting 3 weeks for delivery). I assembled it, installed it, adjusted it per the manual, and I get the same thing. It definitely needed rebuilding, but the problem has not changed. I have a Weber DGV manual choke on my 1275. It idles great and seems to be ok with low RPMs. It's when I try to get the RPM up that it hits this flat spot and wants to die. The fuel system I'm pretty confident in. Not sure about my distributor. I have an electronic distributor that looks kind of tired. I have a brand new one but I'm not confident to install it. I can't even find the darn timing marks on the pulley. Anyone have any suggestions?

 

[Jim_Gruber]

Timing marks are on the underside of the pulley. You need to stand on your head. Unless you have a remote pointer kit sort of a time by ear. Could be your mechanical / vacumn advance is not working properly. Isn't that some sort of issue with Weber/s my brain is telling me. Someone on the list who uses a Weber will rerspond I'm sure.

 

[Midget78]

Ed, make sure your electronic ignition is working properly "all the time". Part of the issue I had before I even put the Weber DGV kit on mine was partially the distributor and not entirely the original Zenith Stromberg that was on it. Yes, the Zenith was on its way out as those things are finicky but the electronic ignition was coming and going when it felt like it which I didnt realize until I put the Weber on. Once I got that replaced with a Pertronix unit I was able to tune the carb properly (Very easy to install as they give you instructions where the wires go - 10 minute job). Now one important note: As you increase the throttle, fuel delivery and pressure becomes more critical and regulated. I dont know if you have an in-line fuel regulator? Are you using the mechanical fuel pumpp on the motor still? The weber maunals say they like around 3 to 3 1/2 lbs of pressure to operate properly without spitting and farting. Check and make sure you dont have a vacuum leak starting around where the throttle linkage is at on that side of the carb. Depending on how well that was setup that shaft going into the carb to the butterfies gets worn and allows a vacuum leak in time (But I dont think thats it if your problem only occurs at higher rpm).

 

[lbc_newbie]

Gonna dig into this today. I'm dying to get this on the road! I have an electric fuel pump that seems to put out pretty well. I'll check vacuum today. I have a MityVac that might come in handy.

 

[Morris]

If you get past the "flat spot" does the engine pick up again?

I can't speak from experience, but I have read many posts by DVG owners complaining of a flat spot.

 

[lbc_newbie]

Nope. It just dies....

 

[texas_bugeye]

I would check those connections to the coil and the dizzy if you have a have a bad connection or a bad coil you could be down on voltage that would put a damper on firing the plugs at high RPMS. Also check that the coil wire is firmly seated in the coil and the cap.Check for carbon tracking under the cap clean it up with some contact cleaner. Check the conditon of the rotor if you recently purchased It maybe one of the bad boys that have been going around.

You said you have a DGV the flat spot on them happens at about 2400 2800 under hard accell coming out of the idle curcit if you push it slow does it still happen?
what about applying some choke does it do the same thing?

 

[lbc_newbie]

I replaced my old worn out electronic distributor with a new Lucas electronic distributor. The internal wires on the previous distributor were worn through by the shaft inside the cap. I installed my new one with #1 at TDC, but got confused when I read this in the manual:

"Provided that the crankshaft has not been turned, the rotor arm will be opposite the segment for #1 plug lead."

Does this mean I'm 180 degrees off on the installation? I had the rotor point at #1. I can't get it to fire up. It just cranks. Coil is providing spark.

 

[jvandyke]

"Provided that the crankshaft has not been turned, the rotor arm will be opposite the segment for #1 plug lead."

Read it like "rotor points at the #1 contact point on the distributor cap" "opposite" means, "across from", "next to" "pointing at".
If you put it back just like it came out it may just be the timing is off so much it won't fire.
Maybe this will help.
https://www.youtube.com/watch?v=hpp67aqwM2Y&feature=related

 

[jvandyke]

oh, you have a 1500, little different then

 

[lbc_newbie]

NO NO NO... 1275...

 

[lbc_newbie]

Great video.. I'll have to crawl under it next weekend and run through the You Tube process. I might have had #4 at TDC. In that case, it would be 180 degrees off. I did have the rotor in the correct position, but not on the firing stroke. Which might explain the engine not firing. Darn! I was hoping to cruise it to wine tasting today!

 

[jvandyke]

oh good, then that video should get you static timing darn close, I think 1275 would be 8 degrees BTDC though, other than that, video applies, check me on that 8 degrees.

 

[lbc_newbie]

Newbie question....which is the low voltage lead on the electronic distributor? Black wire I'm guessing...?

 

[jvandyke]

the little one, not the big spark plug like wire from the middle of the coil, there's only one little one

 

[lbc_newbie]

It's virtually impossible to see the timing marks on this engine the way it sits. It is completely out of my line of sight with the cross-member in the way. :madder: I would need a mirror to see it. I guess the 1275 sits differently than the 1500 in these? To the mechanic she goes!! Let him deal with it....

 

[lbc_newbie]

I got the darn thing to fire up yesterday with the new Lucas electronic distributor. Procrastinating taking it to the mechanic. Timing is probably not exact, but it is starting up at least. I STILL have the flat spot at 2800 RPM. To sum it up: New electronic distributor, cap, rotor, wires, rebuilt Weber DGV carb, new plugs, electric fuel pump is good, and vacuum is good. I heard mention that it could be the float adjustment. Anyone have any idea on how to adjust that?

 

[Midget78]

Ed, Honestly I wouldnt mess with the float adjustment as I have seen how this can open a whole nother can of worms. Plus, my personal opinion if it was the float the flat spot wouldnt just occur at one specific point. You would have noticeable problems all over the rpm scale. I would try and get the timing for sure down pat then start thinking about other areas. I know its frustrating and I probably didnt help much but I found that I created more problems as soon as I started guessing at different things being wrong. I remember when I got the rebuild kit for my carb. I found out that the kit really only rebuilds that carb about 60% and the rest is actual measuring and smoothing different areas and surfaces that you have to know about for it to come out right. Hang in there!

 

[jcatnite]

Ed,
Like everyone has said, you need to be 100% on the timing before you mess around with the carb. Once you get the timing right the Weber is a pretty simple carb. I had a flatspot off idle with mine. The biggest problem I had ended up being too lean on the idle jets. I fattened them up quite a bit, (and lowered my float height)and that brought my idle in line. I'm able to idle at 600-800 rpm at 12 BTDC now. Before I was lucky to get 1200 stable rpm at 16 ro 18 BTDC. I have a great deal of information regarding float height but I think it is at work. Instead of trying to paraphrase it, I would rather wait until tomorrow and I will attach it to this thread. He had me setting a rather low float height (at least it seemed low in my mind)
JC

 

[lbc_newbie]

Motor is shot..... cryin' in my beer..


Well, dunno what I'm gonna do now... looks like my engine is shot. 170-60-160-170 on the compression test by the mechanic. Need to find a reasonable 1275. I'll be crying in my beer tonite!