Engine stutter

The age old problem.

I have a 1600 in my Thing. It has a new coil, 009 distributor, PICT 34 carb, plugs and wires.

When I apply the throttle it stutters. I don't even have to be gunning it and it does it; steady starts from a stop will induce the most obnoxious of hiccups in the thing. I end up tapping the throttle with the clutch in till it grabs.

I read that aircooled.net has a single vacuum centrifugal distributor that seems to correct the problem. But, I also read that they want about $200 for it.

Is there another way I could solve this problem with having to buy a new distributor?

Mathew

Reply to
Mathew
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If you're oprning the throttle slowly and it still stutters, it may not be an 009 prob. Other possibilities are: weak spark (points not gapped, bad condensor, wires, etc.) poor accel pump jet delivery lack of manifold heat (though this is less pronounced in summer)

Speedy Jim

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Reply to
Speedy Jim

Though the distro is brand new, I suppose there is always the chance that a bad component got by.

By accel pump I assume you mean fuel pump? Or a part on the carb?

Mathew

Speedy Jim wrote:

Reply to
Mathew

It takes some work to get rid of the "009 flat spot", but it can be done. You should start by increasing main jet size in the carb by 5 or

10 units. You probably have something like 125 in there now. (That's like 1.25mm) Then adjust the accelerator pump to give maximum squirt. Then adjust the ignition advance so that you get 32 degrees of MAXIMUM advance. That should be achieved at around 2000-2500 rpms, so just rev it up to 3000 and check timing while it's revving up there.

Invest on a strobe timing gun with a turn knob dial and gauge in the back for easy adjustment to any degree accurately. Oh, and learn to use it ;)

After all this you should be much better off, but you may still have some hesitation left. The next remedy is fine tuning the distributor, and it gets a little tedious there. Involves changing the distributor's advance curve by way of messing with spring pre-tension, spring stiffness (replacing springs) and bending travel stop tabs. Not pretty. Once you get the hang of it, most of this can be achieved from outside of the dizzy without teardown. I wouldn't recommend this for anyone who doesn't truely understand the way a distributor works. Come to think of it, if you did you wouldn't have posted your question in the first place... ;)

Jan

Reply to
Jan Andersson

Good points there Jim. Manifold icing can happen in fairly warm climates too, if air velocity and ambient humidity are in favor of it. This is usually caused by clogged heat riser tubes on the intake manifold.

Jan

Reply to
Jan Andersson

Part on the carb.

(Sorry for stealing your moment Jim ;)

Accelerator pump on a 34 is adjusted from the right side of the throttle shaft. There's a lock screw in the linkage piece that is attachjed to the throttle shaft. Loosen the lock screw to be able to adjust the arm pieces it held together. By changing their position in relation to each other, you adjust the accelerator pump. You should be able to see one end of the adjustment scale marked "+" and the other "-". I'll leave it up to to figure out what they mean :)

Jan

Reply to
Jan Andersson

Actually, manifold heat is there for a different reason. When the throttle opens and the accel pump dumps raw fuel down the throat, the fuel can load up in the manifold, rather than being swept immediately into the cyls. That results in a very stubborn hesitation.

But with a "hot spot" right under the carb, raw fuel is immediately vaporized and carried along with the bulk of the mixture. That's why the "heat riser" preheat tubes are thermally "joined" to the manifold under the carb by the alum casting.

Carb icing does indeed occur in warm (10C) temps, especially when humid, due to venturi effects in the carb throat cooling the air down further. Although manifold heat may transfer a bit of heat to the carb, the primary solution is to introduce heated air into the carb.

Speedy Jim

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Reply to
Speedy Jim

Mathew,

Had the same problem and threw the 009 out the window. Check this out:

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Worked perfectly for me right out of the box. Don't forget to re-time the motor once it's installed.

Larry

Reply to
Larry St. Regis

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