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Spitfire help, my spit won't run

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simpzimmer

simpzimmer

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I tried to crank up the Spitfire this morning. I had let it sit for a few months. Bad Idea. I replaced the diaphram in the carb. It had a hole in it. When I cranked the car, it idled, but wouldn't do much else. I tried the adjusting screw, but nothing really changed. The car will idle, roughly, but won't respond to anything else. I try to give it gas, and nothing happens. I replaced the diaphram again to see if I had a bad one, but nothing changed. Any ideas?
 
Just for the point of information, when you say nothing, does that mean when you mash the loud pedal to the floorboards it stays at idle, does absolutely nothing else, no change in sound or engine speed?

"I tried to crank up the Spitfire this morning. I had let it sit for a few months. Bad Idea. I replaced the diaphram in the carb. It had a hole in it. When I cranked the car, it idled, but wouldn't do much else. I tried the adjusting screw, but nothing really changed. The car will idle, roughly, but won't respond to anything else. I try to give it gas, and nothing happens. I replaced the diaphram again to see if I had a bad one, but nothing changed. Any ideas?
_________________________
Greg S. Simpson
Teacher"
 
Right, it stays at idle when I push in the gas pedal. It seems as though there's a slight change in idle, but barely any.
 
This may be too obvious, but is all of the throttle linkage connected correctly??
 
Yeah, with that answer I do believe we are somewhere.

Throttle linkage off, broken, shaft snapped in body of carb, etcetera, etcetera.

Step one, with an assistant (and engine should be OFF) inside the car, you head under bonnet, have them slowly mash the loud pedal down.
Watch and see if the shaft rotates 90 degrees.

If it doesn't go 90, or moves just barely, or not at all, look for linkage issues, pedal to carb.

If it does, remove air filter, lift piston, using a flashlight observe the throttle plate (butterfly) while assistant tries again.
If linkage moves and butterfly does not, report back.
 
I can manually open the gas via the carb, but nothing happens. I know this is a vague question, and there's probably hundreds of things that could be happening, but I'm limited in my mechanic knowledge and I usually do a lot better if I get advice before I start tearing anything apart. I knew the diaphram was bad. It had a hole in it. A member on here once told me to always check those with running problems. I know the fuel pump is working. I took off the fuel hose and it's pumping gas. To me, it seems that something may be stopped up in the carb, or something's wrong with the electronics that's keeping it from firing properly. I figured I would consider changing the plugs and wires next before tearing into the carb "which I've never done before."
The members on here have usually dealt with these cars much more than I have and know the usual places to look for problems. I've found asking first can sometimes save a few steps. And thanks to everyone in the past for all the help.
 
The butterfly opened when the gas was pushed. I had my son test the pedal for me.
 
Okay, so mechanical externals are working.

That is good, sort of.

Now, start it up, air cleaner off, open the throttle by hand and keep you face away from the venturi (inlet of the carb), does the piston move up at all when you do this?

If it was me, I'd have my assistant sit in the car next to the kill switch (ignition), and I'd open the throttle a little, and pull the piston up a little with my finger.
If the RPM's come up, it's most likely a vacuum to the diaphram/piston problem, but it has been 25 years, maybe 20, since I worked on one of those type carbs.

If the piston comes up with opening of throttle, without you having to manually operate piston, perchance was the needle valve attached to the end of the piston when you pulled the piston to replace the diaphram?

Needle is the long pointy thing that hangs off the bottom of the piston, you can see it when you lift the piston by hand (engine off).
 
Before I read the last post, I started the engine, let it idle, and manually pushed up the piston. The engine revved up, quickly I might add. So I've probably got a vacuum problem? I'll update if I find any clogs or holes.
 
Yeah.
Diaphram blown (which generally you can tell with visual inspection), diapramp not seated in ring, diaphram retainer ring not mounted properly or at all, vacuum port plugged....OR>>>>>>>>>>>>>>

Don't I remember the vacuum port being on one corner of the top cover?

Any chance you have the top cover rotated on or two quadrants off the port and nothing is happening?

Take the top cover off and make sure the ports line up!
 
Hah! You guys are great! I didn't notice that the diaphram had to be positioned in a certain direction. The two portholes on the bottom of the piston had to be facing the engine. I turned it around and she fired right up. Rookie mistake.
thanks yet again for the help. When I bought this car I made it a policy that I would learn everything about it as I go. No mechanics unless absolutely necessary. This forum has saved me more than once.
Happy motoring!
 
And here I had to drag that up from last century's memory banks.
 
:lol:

Good one, Sir! :wink:

Never again will Greg miss the alignment tab on a Zed-S! :laugh:
 
First question should have been. "Has it been run since you fixed the diaphragm"
 
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