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sudden low idle

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jvandyke

jvandyke

Luke Skywalker
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I've been thrashing my little Midget quite thoroughly lately and loving it. This morning on my daily joy ride to work, right off the bat, idle would drop to 500 or lower and it would barely tick over, would likely have stalled (especially if the clutch were in) had I not nursed it along at the lights.
I can see a higher idle via a vacuum leak, but lower? I just tweaked the idle screws a tad in parking lot but have not fired it up to check if that will suffice. Just wondering why that would happen?
I did just install a XR700 ignition but that was days ago. I should go back through the timing I guess. Maybe timing slipped a bit? Sure runs down the road fine though, better and smoother overall with the XR700 but it could be it is just timed better or at least differently then the points.
 
If thetiming reterded, losse clamp, then that might explian it. I like to take a Sharpie marker, and when I get my timing dield in where I want it, make a index mark from the dizzy to the clamp, that way I can tell if if ever moves, an old overtighten/warped clamp and often be the culprit.
 
Okay, I've done that so I'll look at my marks and double check.
 
My mom's Midget was experiencing the same symptoms earlier this summer. As it turned out there was a (major) vacuum leak between the intake manifold and cyl head. The nuts were loose and if I grabbed the bottom of the carbs and lifted up I could actually move the carbs up and down about a half inch at the outside edge. I guess a vacuum leak at the cyl head would actually be leaning out the mixture so greatly that it couldn't idle well but then when the RPM's come up the drop in manifold vacuum and velocity of the charge would overcome the gap.

Just another suggestion of something to look at. Good luck!

JACK
 
Good call, I've had trouble keeping the seal good there, stupid Pacesetter.
 
Snugged down manifold nuts. Still low, checked timing was closer to 5 BTDC I set to a bit closer to 10 but still had to tweak the idle at the carb, hmmmm. Bit weird. Sure runs nice though. No complaints.
 
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