TheSamba.com :: View topic - Carb leaking mass amounts of air/driver's side + strobe '?'

Tue Nov 03, 2009 4:07 pm

My carburetor Solex 30PICT-3 is leaking air from the same side where the vacuum line runs out to the distributor. There's also a bit of air that I can feel flowing from the front of the carburetor.

It's causing my engine to whistle while idling. It's like transversing two peaks of mountaintop with a wee lil valley in the middle there, and the wind is playing it's music.

Could this be gaskets alone or something simple? I'm thinking I caused this problem. When cleaning my carburetor, for instance, I removed the big idle screw, cleaned it, and threaded it + it's lil spring back in. I attempted to remove the smaller fuel mixture screw (I believe it's called). It wouldn't come out, so I just screwed it back in there.

But like I said, it's blowing lotsa air. lotsa. Where should I troubleshoot? The air jetting screws (I also think they're called) are located on the opposite (passenger side) of the carb. I do not think they are the problem.

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Also, where do I hookup the timing light (strobe gun)? I clamped the #1 spark wire, hooked the postive clamp to the negative side of the coil, and the negative clamp to a ground.

It worked, but my little green condensor wire (from dizzy) fell of alongside the strobe clamp. My battery was dead after that.. (I've got a cruddy battery). Got one strobe flash and the engine lost major power (would attempt to die with each trigger press on the timing gun).

Tue Nov 03, 2009 4:33 pm

Not sure what you are describing here. Are you saying there is air blowing OUT from the side of your carb? The carb works by vacuum so I can't see how it would blow air out... Unless you have a blow-thru turbo setup on your 30PICT-3??
Can you narrow down where this is coming from? If it is a vacuum (air leak into the intake) these do whistle and can usually be tracked down by spraying carb cleaner or WD-40 at suspected spots with the engine running. If the engine RPM goes up, you've found your leak.

By hooking your timing light's positive (+) lead to the negative side of the coil you've disrupted the ignition circuit. The coil normally has just one path to ground... thru the points/condensor. You've created a second path so the primary coil circuit doesn't completely collapse. Connect the timing light somewhere else. The positive side of the coil may work, but you will be stealing current from the coil. Not good if you have a bad battery.
If you have an alternator you can connect to the large terminal that goes to the battery. This is a 12v+ source. Don't do this on a generator, too many volts come directly off the generator. Or run the power cables straight to the battery. If your battery is weak, charge if or replace it.

Tue Nov 03, 2009 5:10 pm

Looks like I will have to troubleshoot some on the air blow out. It could very well be my exhuast (I don't have any of my exhaust clamps on) or fanshroud even.

I sure hope I can rule out the carburetor. (I don't have a turbo setup or anything fancy) :cry:

I'm running a generator at present. I understand the stealing power away from the coil to dizzy circuit, thanks to your explanation. Makes sense.

I'm not sure about the strobe light reaching around to the battery though. I believe the cables are too short. I'll have to improvise.

Tue Nov 03, 2009 5:29 pm

monkbonk wrote: Also, where do I hookup the timing light (strobe gun)? I clamped the #1 spark wire, hooked the postive clamp to the negative side of the coil, and the negative clamp to a ground.

It worked, but my little green condensor wire (from dizzy) fell of alongside the strobe clamp. My battery was dead after that.. (I've got a cruddy battery). Got one strobe flash and the engine lost major power (would attempt to die with each trigger press on the timing gun).
...mmmkay...
there are multiple places inside the engine compartment to find (+) power.
the (-) negative side of the coil is not one of them.

Tue Nov 03, 2009 5:32 pm

I use the strobe light with the positive clamp attached to the positive side of the coil all the time. For just timing the engine, I wouldn't worry about stealing juice from the coil. Just watch the cord so it doesn't dance with the fan belt.

Tue Nov 03, 2009 6:21 pm

Hook that timing light up to your jumper cables.

Wed Nov 04, 2009 1:29 am

Randy in Maine wrote: Hook that timing light up to your jumper cables.

Excellent suggestion! Everyone should have a set in their car and breaking them out for the occasional tune is not too difficult.

Randy, I'm sure I've heard you say that before, but forgot all about it.

Thanks for the reminder.

Wed Nov 04, 2009 1:28 pm

ashman40 wrote: By hooking your timing light's positive (+) lead to the negative side of the coil you've disrupted the ignition circuit. The coil normally has just one path to ground... thru the points/condensor. You've created a second path so the primary coil circuit doesn't completely collapse.

Right. When you hook the gun to the negative side of the coil, and pull the trigger, then engine starts to die. So don't do that. :-)

Quote:
Connect the timing light somewhere else. The positive side of the coil may work, but you will be stealing current from the coil. Not good if you have a bad battery.

The positive side of the coil is the usual place to connect the power lead for the timing gun. If it draws so much current that it's causing voltage to drop, you have worse problems.