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idle but no throttle

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Woodie

Woodie

Jedi Warrior
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Ok My new to me 70 midget has not run for 2 yrs. and today I started it. Before I did, I set the carbs to the following..idle screws 1 1/2 turns in from off the cam, mixture screws out 2 turns. (twins SU's) The car started and idles at 1500 -2000 I think, But when I step on throttle nothing no increase in revs, adjusted the mixture out a bit , nothing then in a bit and the idle smoothed out, but still no increase in revs with throttle. But as I let off the idle it stalls. On sunday I cleaned the bowls jets and plungers, made sure all was free and movng easily. So is it to rich or too lean or something else. ??
 
Is your throttle linkage actually connected and working? That would be my first thought. Make sure the butterflies are actually opening when you mash the gas pedal.
 
oh yes the work I check the lincage. It opens the butterflies on both carbs. I am stumped....
 
Strange... My second guess would be a huge vacuum leak maybe?

Try lifting the piston on each carb very slightly while its idling and see what it does. Increase in RPM indicates rich mixture and immediate decrease indicates a lean mixture.
 
well yhe vacuum to the distributor is on and the vacuum from the carbs to the canister under the water pump is on. Any others ? Is it maybe timing being off?
 
If it idles at 1500, then it should take throttle. Do your dashpots have oil in them? I'm thinking (like above) you might have a vacuum leak. Check the manifold nuts, and carb nuts, and any lines that might be cracked or loose fitting.
 
OIl in dashpots ...check. I will recheck all lines next time I get to the car (saturday) it is 20 miles from me and I can't be there every night. If I can see no possible vacuum leaks, should I reset the idle to 1 1/2 turns in and then close the mixture and try to start the car , then open the mixture (richer) 1 flat on both carbs at a time until it starts? Or another possibility but on both carbs??, could the float bowls not be working correctly??
 
I'm thinking out loud a little here... (uh oh <grin>)

If the butterflies are opening, then unless you have a major vacuum leak somewhere (or an almost completely plugged intake manifold... hmmm, there's not some kind of varmint nest in there is there?), the engine has got to suck more air (I would think). If it does, and there's a fuel feed problem, it would lean and sputter...

I'm baffled. I don't think the mixture is a problem, and even if it were timed poorly, it would still try to accelerate (I would think).
 
2 more thoughts,

What if the ports in the plungers were blocked. They would not rise when I applied throttle. What would happen.?
Second thought, the fuel pump. It works, but if I disconnect the fuel line at the first float bowl ( after the in line filter and turn the key on, how much fuel pumps out of the line? Lots in a constant gush, dribbles, or it just sort of pours out ?
 
uhhh,, isnt that impossible?!.....check the ball on you throttle cable...most likely you just feeling the spring on the gas pedal and you cable isnt hooked up at all!....try revving the car by hand from the carbs to eliminate most other ideas......zimmmy
 
The bonnet is not on the car...this is from starting the car while standing beside the engine. The windshield is off too. I am pulling up on the throttle cable, and have watch the butterflys open when the top of the carb is removed and the plunger and needle are out. (car not running of course) Never had this problem on my spitfire.....
 
Something is very obviously wrong with the carbs air flow. Wasp nest? Spider house, vacuem leak, sticking damper, something.
 
yes they sslide with no binding. When I put them on without oil and the top of the dashpot off they slide down and go clunk. With oil and dashpot top on they slide down slowly. The needles seem straight. I leaned out the carbs to bring the jets even with the bridge, then lowered each carb 12 flats. That is where I am. All I can think of now is the float bowl valve might be semi open to only allow enough fuel in to idle, but when I open the throttle, the engine does not stutter and stall from lack of fuel...nothing happens. The dampers rise a bit ...I tightened everything.
 
Have you cleaned out the float bowls and the float needle seats. I tell ya something is in there keeping fuel or air or both from entering the cylinders.
 
yes but maybe not well enough. When I had thefloat bowl covers off, I wiped the covers and the floats down, the bowls had fuel in them, I gentle pushed the valve pins up to make sure they moved. I reassembled. I blew air through the jets in the carbs (while dampers and needles were out) back into the float bowls and had fuel come out the overflow hoses. I can always reclean these. I go back to a question earlier re the fuel pump andf uel flow, How hard is the stream of fuel from the fuel line just before it goes into the float bowls??
 
Another thought to see if enough fuel is coming from the float bowls... Can I remove the dashpots and dampers and needles, and "try to start the car" to see how much fuel is actually coming through the jets, or do I just need to turn the key on to get the fuel pump working...

Having seen the dampers rise and no real changes happen when I adjust the throttle speed or mixture my guess now is fuel starvation...
 
Thats it, but if bowls are full it is getting that far, take out the float needles and make sure that is clean all the way to the manifold. Blow it.
 
It's not unknown for the needles to be loose in the pistons. The piston rises, but the needle stays down. But I'm sure you would have noticed this.
D
 
there seems to be a bit of "damping" in the needle. By that I mean it is not hard mounted in the damper, if you pull or push it moves about 1/16 up or down. Not enough to cause the problem I have I doubt, even if this is a problem. I figure on saturday when I next get at the car, I will take apart the carbs again, and clean the float bowl valve, and the jets really well . lots of carb cleaner and air blowing then.
 
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