View Single Post
  #1   IP: 64.203.208.102
Old 02-25-2019, 10:52 AM
Smuggli's Avatar
Smuggli Smuggli is offline
Senior Member
 
Join Date: Jul 2014
Location: St. Paul MN
Posts: 22
Thanks: 2
Thanked 1 Time in 1 Post
Carb + Alternator Idle Probs and "Clicking"

I'll try to be concise. But have learned that all the details help you help me more effectively. I believe I have resolved my rich running and fouled plugs. But am still experiencing a "surge" at lower RPM and idle as well as "clicking/clanking" sound from the general area of the alternator. I will be going offshore and need to make sure we are all dialed in. So here's the background on my early model A4:

1.) In Sep. I replaced the entire ignition system (MMI electronic ignition installed, coil, wires plugs etc.). As part of this I had to remove and re-time the distributor. I tried my best to get this right by following the instructions, but my setup does not allow me to "tune" the distributor under load by rotating the distributor unit. There is a fixed clamp instead of the hold down bracket. It seems to run right, but I could have been running the last 2,000 miles slightly mis-timed.

2.) In Oct. I had some drop in power and removed and cleaned the carb (basic cleaning and blow out, didn't remove the jets. It's possible that I did not get the mixture right on this old style carb. (It has the adjustable main jet which was loose to the touch).

3.) We seemed to run fine after that. But about a month ago, I noticed my plugs were fairly sooty. I cleaned them and kept going. I was still getting some lower rpm range engine surge and power loss followed by recovery. At lower RPM she would die on the downside of the surge. Then I heard a depressing "clunk" and significant power loss. I was running on 3 cylinders (or so I felt), we tried to limp to the next stop, and "clunk", another big drop. With max speed down to about 1.5 mph (we can usually pull 6 mph). Checked my plugs, and yes, severely fouled and two were so bad there is no way they could fire.

4.) Determining that this was "hopefully" just the result of running way too rich, I first deduced my choke cable had slipped it's bracket. I broke the little arm/screw that holds the cable and fashioned a new one. Re-set everything and adjusted both main jet and idle screw and re-balanced the stop screw. Still ran rough at lower idle. Verified the choke was fully opening and closing properly.

5.) So I removed the carb, and cleaned it. Then it would not start at all. I had excessive fuel in the bowl and removed the carb again and replaced the floats and float valve (which was damaged as it turns out). Now it starts, but still idles a little rough (surge). The "clicking" noise persists. Added some marvel Mystery oil in each plug and to the gas tank (hoping to eliminate a slightly sticking valve). No joy.

6.) Finally have everything dialed-in from a mixture and carb perspective, I noticed I need to run the choke a little longer than I used to to keep it going at cold start but that's OK with me. Now to the clicking and the surge. At low RPM and especially when in gear fwd, the "clacking" and surge are significant enough to hear from the cockpit. I put a stethoscope all over but could not find a discernible source. Rather it seems to be coming from the general area of the alternator, but I cannot be sure.

I have a 2 year old Moyer 120 amp alternator with the 26" belt. I noticed some squealing at start a while back, and am seeing a little black powder under the belt indicating that the belt may not be tensioned properly, but as the new belt wore a bit it seemed to go away (I know). So now I am wondering if I wore out the bearings. Although, I am getting a consistent and correct voltage out of the alternator.

I should also mention I found a pin-hole leak in the exhaust where the manifold attaches to the engine with a spotlight. To get through this, I just added some gasket goop to that area in hopes of eliminating that as a problem. Not sure if that worked yet.

So the question remains. How best to diagnose the problem? Can I run the engine with the alternator belt removed and see if the clicking goes away? If not, would the next step to be run the engine and remove the plug wires one at a time - not sure if this is advisable (maybe a valve issue?). I've been fiddling with this for 2 weeks now and we need to keep moving. Any suggestions on how to streamline the diagnosis or resolution would be most helpful. And as always, you guys are awesome.

Scott Muggli
S/V Anna Rita

Last edited by Smuggli; 02-25-2019 at 11:03 AM.
Reply With Quote