rpms at idle

My 2165 cc Raby type 1 engine idles at 1300 rpms. If I turn it down to under a 1000 rpms it tends to sputter and stall. I have a severe knowledge deficit when it comes to automotive mechanical issues so a rudimentary explanation of the issues would be appreciated. Is 1300 too fast ? If so what can I do myself to fix it ? thanks

I think 1300 is a bit fast for idling. I idle at 900-1000 with a 2176 and have no problems.

David;

If Weber IDF's, make sure all idle air bypass (small, at bottom, with lock nuts) screws are fully closed, then turn in GENTLY idle mix screws (springs on them) until they just barely seat, then unscrew them 1 and 1/4 turns. Unscrew idle speed screws (the ones that touch the throttle arm) until they don't touch, then screw them in until they just touch, then screw them in 1/2 to 3/4 turn more.

Start the car and let it warm up, then speed up or slow down each idle speed screw the same amount until you get 900 or 1,000 RPM idle speed - don't mess with the idle mixture screws yet. If it still won't idle down or idle smoothly you probably have a vacuum leak (carb to manifold or manifold to head gasket).

If Dellorto DRLA's, same as above except the intial setting for the idle mixture screws will be about 2 3/4 to 3.0 turns out from barely seated. And make sure vacuum ports (if any) are effectively plugged.

If you are non-mechanical and the above doesn't help find a good VW air-cooled performance mechanic or check with your local area VW owner's club for help. Or a local performance motorcycle shop.

(Message Edited 3/26/2003 1:52:15 PM)

thanks george. Have you considered moving to Boston ?

If I move it will be further south - I HATE COLD WEATHER. Any of you are welcome to email me about carbs, etc., or "in extremis" I can talk you through carb stuff on the phone. There is no magic to carbs; they are really pretty simple devices once you understand how they work and what can go wrong.

I'm doing a Weber IDF "show and tell" soon in Silver Spring MD for Karl; this coming weekend is probably rain so if his scedule permits it will probably be the following weekend. Karl probably wouldn't mind if anyone from around the area came and watched and asked questions (but his wife isn't going to feed us).

George
Why not tape the event and make the tape available to us - at a price of course.

Richard

"If it still won't idle down or idle smoothly you probably have a vacuum leak (carb to manifold or manifold to head gasket)."

Just to beat it to death, the procedure to locate a vacuum leak is quite simple. Get a spray bottle and aim the water over ANY AND ALL joints in the carb/manifold area and look for water being sucked in. If there is any doubt about a rust spot, check that too!

Another problem may be a plugged idle jet(s) in one/both carbs. This last will require the services of a mechanic.

Unfortunately the spray bottle test for vacuum leaks doesn't always work very well; I have made a tool for IDF and DRLA manifolds that isolates port runners and can be air pressurized with piston at TDC on compression (which will also show if your intake valve is leaking, or the leak is BETWEEN the port runners at the manifold to head gasket, or the casting is porous).

Pressurize to 15 psi then watch the gauge to see if it drops. If it does, you listen with a piece of rubber tubing for a hiss around the manifold base, down the other port runner, and down the oil filler (for a leaking valve).

The "tool" is simply a 1/2" thick piece of aluminum drilled/tapped for an air hose fitting in the center with mounting holes drilled to fit over a single port runner's carb mounting studs.

(Message Edited 3/28/2003 2:32:07 PM)