Ghost operated Midget

[donandmax]

I really dont know where to start on the carb.problems of this 79 Midget. The idle on this car was real rough. It wouldnt idle but would just die. On the road it runs like a scared rabbit. Smooth and powerful.Take your foot off the pedal and it drops to zero rpms and dies and the warmer the weather the worse it gets. I replaced the carbs and the situation was even worse. The engine just sitting there and running would go up to 3500 rpm then down to 500 rpm then up and down and this went on and on. I took the oil cap off and it went to 2000 rpm and it stayed there put the cap back on and it went down and died. Started it back up and it went to 4000 rpm and I shut it off before it exploded.I do run a ignitor ign system. Im at a loss as to whats wrong with this crazy engine, Disconnect any hose (emmission) and you get different results. As it is now I'll never be able to run this car again until I can sort out this insane engine. I cant figure out if its the distributor i.e. electrical or a carb problem Remember I changed the carbs and got basically the same results. Man I need HELP..Hope someone has a solution because mechanis around here think Im nuts. I dont take it to them because no one around here knows anything abouth thrdr little cars.(zenith carb)
Thanks for your responses ahead of time..
Don

 

[JPSmit]

Don, are you still running the Zenith Stromberg? I replaced mine with an HS4 SU - I also took off the pollution stuff. I strongly suspect you have a vacuum leak. This would account for the mixture being out of whack. Have you tried spraying WD40 around where the carb meets the manifold or the manifold the engine? do the revs change? try that first.

 

[donandmax]

John, will try your suggestions. Is it possible to take off the intake manifold without removing the 1500 engine ? And where would I get an HS4 SU carb.( here in U.S.) I suppose the zenith S. manifold wouldnt fit the SU correct ?
Don

 

[Deleted member 8987]

Vacuum leak as in PCV valve broken, misassembled, or jammed.
The clue to me was the removing of the oil fill cap.
Add to that contaminated oil (more common than you think), which when it gets warm (where your problem is worse) the gasoline in the oil evaporates and is sucked into the intake.

Find your PCV, find where it connects to the intake runner, remove it and temporarily plug the hole in the intake and see how it does.

Reason I suggest this is A) it's quick and easy, B) won't cost you anything, and C) eliminates at least two possible sources of problem at once.

If all is done and it IS an issue with the PCV connected, pull the dipstick, step away from the vehicle, pull out your Zippo, and try to light the oil on the end of the dipstick.

Alternatively, you can smell the oil on the stick, looking for gasoline.....

 

[donandmax]

Toc, I see no PCV valve anywhere on this engine nor anywhere to install one Interesting to say the least. This is a 75 or 79 engine. Hmmm didnt think about that until you mentioned it though. I have the aluminum valve cover on it but no hole for a PVC valve either on it or the old cover. I once removed all the smog crap and it made the engine run terrible so I hooked everything back up and it ran fine until this latest incidense. anything above 80 deg F will cause the engine to die at idle speeds. Now of course it does as mentioned above.I really think its an air problem somewhere. But as I disconnect the smog hoses one by one I get different idle symptoms now if I start up the engine it doesnt idle but races at ungodly high speeds and you have to shut it off becauses it then doesnt respond to any adjustment. Could the Pertronix ign. system cause these idle problems ?
Don

 

[Deleted member 8987]

Carbs meaning dual carb setup. Should be a "Y" pipe off the carbs, to an elbow that fits to the side of the valve cover with a restrictor inside the elbow.
5/64" hole, apparently often goes missing, could have rotated I suppose.
1970 MG went to a "closed" PCV system, so if 75 or 79, should be there.
That's for a B, but PCV's were required before any other emissions devices, so, say, 1966? I read somewhere 1961, but I was around then and do not remember PCV's until at least 65.

 

[donandmax]

Toc, restrictor is in place in single ZS carb.

 

[bthompson]

I'd think it was a vacuum problem before I blamed the ignition. Zeniths are <span style="font-style: italic">picky </span>for vacuum balance, and <span style="font-style: italic">any </span>air leaks in the system will drive the mixture richer. Lots of little leaks will act like one big one. Just some thoughts off the top of my head, from experience with my own ZS:

When it dies at idle, does it feel like it's choking on fuel or starving out?

You mentioned all the emissions bits are still on. Do you have the original air cleaner? Is the run-on valve working? Is the EGR rusted open? Are all the air hoses in good shape?

Do you have the water choke or the manual choke? (On a ZS the "choke" is actually a controlled air bleed)

Are you sure the float bowl vent is open?

Is the piston diaphragm torn or damaged?

Be careful checking for leaks and make sure the gaskets are tight.

To answer some of your questions:

You CAN take off the manifolds without removing the engine. Not all that hard: the bolts underneath are the trickiest bits.

The SU HIF4 like JP was talking about bolts right onto the ZS intake manifold with very little modification. (Elongate a bolt hole into a slot basically.) A quick and easy fix for us 1500 guys to exorcise the Stromberg demon. I went the Weber route after wrangling with a hopeless Stromberg: don't make my mistake -- use the SU fix instead IMHO.

 

[Deleted member 8987]

Okay, single carb.
Unplug the rubber hose to the PCV fitting to the valve cover, and block it (duct tape will work).
Try it now.
Then test the oil.
If you changed out the carb (single) as you stated, with no change for the better, the chances are slim (but still a chance) that the carb is the problem.
EGR stuck, yes, not as easy to check.
Dave

 

[JPSmit]

John, will try your suggestions. Is it possible to take off the intake manifold without removing the 1500 engine ? And where would I get an HS4 SU carb.( here in U.S.) I suppose the zenith S. manifold wouldnt fit the SU correct ?
Don

Yes you can take off the manifold the two bolts that are shared by the exhaust manifold are a PITA but as said elsewhere, you can bolt an SU right on with about ten minutes work elongating the holes. The carb I used is the rear carb from an MGB the holes don't line up on the front carb. The HI44 is (I think) off a Metro.

 

[donandmax]

Okay, single carb.
Unplug the rubber hose to the PCV fitting to the valve cover, and block it (duct tape will work).
Try it now.
Then test the oil.
If you changed out the carb (single) as you stated, with no change for the better, the chances are slim (but still a chance) that the carb is the problem.
EGR stuck, yes, not as easy to check.
Dave

The line going to the egr valve I disconnected some time ago and plugged the nipple on top of it. It ran alright. I havent hooked it back up should I ? I have now disconnected all the smog stuff. It seems to run a little better but tomorrow morning it will no doubt act up when I first start it. The idle wasnt bad today but you could tell by the exhaust note it was running uneven and stumbling around.When it stalls it sounds like its running out of fuel it just dies and when its cold you almost have to keep the choke on. Way past the time you would normally shut it off. I got rid of the water choke about 5 yrs ago and went with a manual one.if I keep the rpm's around 1500 it will surge up and down almost like someone is pressing up and down on the gas peddle. Thus the title of my tale of woe "Ghost"

 

[Deleted member 8987]

If the EGR is unplugged, that doesn't mean a backfire might have dislogded the seat and jammed some carbon in it.
If you remove it, and place liquid in one port while holding inverted, look to see if the other port gets wet right now.
Damp spot, not the problem, but if it equalizes in a couple of seconds, gona need some cleaning and such.

 

[donandmax]

If the EGR is unplugged, that doesn't mean a backfire might have dislogded the seat and jammed some carbon in it.
If you remove it, and place liquid in one port while holding inverted, look to see if the other port gets wet right now.
Damp spot, not the problem, but if it equalizes in a couple of seconds, gona need some cleaning and such. [/quote
Well for me that is a problem because I do not know how to unscrew the nut thats down in the intake manifold. How to get a wrench on that is a mystery to me. Ive been wanting to remove the egr altogether and find a screw in plug and just plug it off but getting a wrench on that nut seems impossible to me. The one closest to me is no problem.
Any suggestions ? Thanks for hanging in there with me by the way..
Don

 

[Deleted member 8987]

I've done it, but long ago and far away.
If I recall, I took a box end of appropriate size, heated it in a vise with an oxy acetylene torch, and bent it to fit the nut, come up the side, then bend back parallel to the box part for leverage.

Crow's Foot won't work?

 

[donandmax]

I can't seem to find the cause of this constant dying engine, Someone here in town mentioned "maybe its the alcohol in the gas" Never had problem before. What da ya think ??

 

[hooey]

snap-on makes a tool it a 40/60 openend and a haftmoon

 

[Silverghost]

Yup.....blame it on the alcohol!

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[Deleted member 8987]

Well, ignition cannot give you 2,000 RPM idle.
Just cannot.

Vacuum leak. Loose butterfly. Badly work throttle shaft bushings.
Gasoline in the oil.
PCV hose rotted.

I would A) check the oil on the dipstick with a flame to ensure no gasoline.
B) check the PCV hose carefully.
C) Remove the carb and chek the butterfly fully seated (reach around, lift the piston, hold the engine side up to the light and SEE).
D) Check the throttle shaft bushings.
E) Carb float bowl vent.
F) Throttle cable.
G) you haven't added a brake booster to it, have you?
H) then I'd be looking at intake gasket, with a can of spray carb cleaner or some such...if you have never used carb cleaner, it IS flammable, so use something else.

 

[jlaird]

Running old corn oil in the gas will cause big problems.