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-   -   Carb + Alternator Idle Probs and "Clicking" (https://www.moyermarineforum.com/forums/showthread.php?t=10994)

Smuggli 02-25-2019 10:52 AM

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

joe_db 02-25-2019 11:09 AM

Take the alternator belt off. One of my alternators has a bad bearing and makes odd noises and that is how I found it. Note if you leave it off eventually your battery will go dead.

Marian Claire 02-25-2019 02:28 PM

# 1. On my early, 1965, model there are two screws that have to be loosened to adjust the distributor. One is accessible from above like the late model. The other is accessible down low on the aft side of the distributor and is horizontal. You can see it in the attached pic.

Dan
S/V Marian Claire

http://www.moyermarineforum.com/foru...&pictureid=615

Sam 02-25-2019 02:47 PM

I have just have a few minutes so I will have to be brief. I have had my early model 1966 A4 for the last 43 years here in Chicago and never needed rebuilding with original zenith carb and Prestolite distributor [condenser on outside] Couple of seasons ago I had some similar surging/dying problems. Following some forum advise I did the following: pumped out and cleaned tank best I could while still installed [ last inch was not good fuel], changed fuel lines to low permutation [due to ethanol], new fuel filter [old one was looked like it was collecting black gunk faster than I liked], replaced twenty year old electric fuel pump with new facet cube pump, cleaned carb, installed fuel pressure gauge before carb [cheap & informative] and refueled with non -marina gas. Engine ran well and later changed points, plugs, condenser, cap/rotor. Couple of decades ago I lost my old tank pick up tube in the tank and installed a new one 1 1/2 in above the bottom. I would have to say the main culprit was the tank/accumulated old water laced fuel sloshing around and everything else downstream added to problem. Many forum gurus will tell you to add a fuel pressure gauge for better diagnostics.

Sam 02-25-2019 02:54 PM

Also, pulling and replacing a spark plug boot one at a time and noting rpm drop will not cause a problem. I do this every season to check valve operation etc. You will need a long Phillips head #2 screwdriver to access the horizontal distributor adjustment clamp screw.

Smuggli 02-25-2019 04:12 PM

Clicking was Alternator
 
I removed the belt and behold, the clicking/clacking nose is gone. I broke it. Lesson learned. So that mystery is solved. I'm going to replace the whole unit with the 55 amp alternator from MMI. Tom at Indigo felt that this would be a better fit for their new electronic pump kit for their fresh water cooling that runs off this unit. Though the manual pump would work just fine with the 120 amp alternator.

Anyway, I am still getting some surge at very low idle, but I suspect this is a flow adjustment, it may just be a little confused switching between the idle jet and the main jet? I have noticed the main jet will impact the rpm even at vey low (almost quitting) idle. Which is suspicious in it's own right.

I'm sorry I have to ask basic questions like "can I run without the alternator connected" or "can I remove a plug wire while running". I am still learning.

JOHN COOKSON 02-25-2019 05:01 PM

How long has it been since you serviced the advance? If the advance is sticky it will make for squirrely idle and running.
Catch some fuel in a clear jar and hold it to the light to see how much water you have in the fuel.
As noted fuel pressure gauge would be helpful. Now and in the future.

TRUE GRIT

Edit: If closing the choke improves the idle then there is a problem with the fuel system.

Easy Rider 02-25-2019 09:27 PM

I might be away off base here but I wouldn’t be to quick to be determining the clacking was coming from the only two year old alternator. I’m thinking the clacking sound may have been coming from the assessory drive bearings. You might want to try hooking the alternator again and try your stethoscope on the accessory drive or try different belt tensions to see if it makes any difference.

JOHN COOKSON 02-26-2019 02:11 AM

A quick and easy way to check the accessory drive bearing is to push on the pulley with a piece of wood while the noise is happening and see if the noise changes. Be very careful around moving machinery.

Also: The alternator pulley and the accessory drive pulley may somehow not be in alignment. This would cause a lateral force on the alternator bearing and lead to premature failure. The way to check for pulley alignment is to put a straight edge, such as a wood dowel, in the groves of the two pulleys and see if they are lined up.

TRUE GRIT

Smuggli 02-26-2019 09:04 AM

Alignment tip.
 
Thanks for the tip John. I will do that as I expect that was the bulk of my issue.

Smuggli 02-26-2019 09:06 AM

Carb Bowl Full - Causes?
 
Now, of course, I have a carb bowl that's full of fuel (again) after working fine for the last couple of days. So I am guessing the float valve issue again. Bummer to have to rip this whole thing apart and re-tune from scratch for the 10th time.

I am assuming this is a problem with the alignment or the gap on the floats in the carb not shutting off the float valve soon enough. Any other possibilities? I am getting despondent. I just got this whole system dialed in (yet again).

Smuggli 02-26-2019 09:47 AM

Quote:

Originally Posted by Easy Rider (Post 115876)
I might be away off base here but I wouldn’t be to quick to be determining the clacking was coming from the only two year old alternator. I’m thinking the clacking sound may have been coming from the assessors drive bearings. You might want to try hooking the alternator again and try your stethoscope on the accessory drive or try different belt tensions to see if it makes any difference.

Worth doing for sure. Thanks.

Sam 02-26-2019 12:52 PM

When I'm "lazy" and have a carb bowl problem I spray some carb cleaner up through the bottom drain plug with the little tube and spray can cleans it out well and the float doesn't "stick" There are all kinds of threads on carb issues but I found changing out the little "springs" on the float helped a great deal and minimized all of the issues. Also, the comments on the advance in the distributor are spot on. Take the plate off and you will probably see some rusty powder that should be cleaned up and lubricated and two old springs easily replaced that Moyer sells replacements.

JOHN COOKSON 02-26-2019 05:29 PM

Quote:

Originally Posted by Smuggli (Post 115879)
Now, of course, I have a carb bowl that's full of fuel (again) after working fine for the last couple of days. So I am guessing the float valve issue again. Bummer to have to rip this whole thing apart and re-tune from scratch for the 10th time.

I am assuming this is a problem with the alignment or the gap on the floats in the carb not shutting off the float valve soon enough. Any other possibilities? I am getting despondent. I just got this whole system dialed in (yet again).

What float drop setting are you using?
Is there any fuel inside the float bodies?
What does the tip of the needle valve look like?
Did you change the needle valve and then seat at the same time?
Sometimes the seat needs a needs a little dressing down with a sharpened wood dowel before the needle valve will seat.

TRUE GRIT

Smuggli 02-28-2019 09:46 AM

Quote:

Originally Posted by JOHN COOKSON (Post 115883)
What float drop setting are you using?
Is there any fuel inside the float bodies?
What does the tip of the needle valve look like?
Did you change the needle valve and then seat at the same time?
Sometimes the seat needs a needs a little dressing down with a sharpened wood dowel before the needle valve will seat.

TRUE GRIT

I’ve done the whole re-build kit. Cleaned everything twice, new floats, needle valve etc. just happened again. At this point I’m at a loss. In the interest of time, I may just get a new carb.

The float drop setting is just per the instructions for the rebuild kit. Making sure the floats are parallel with the unit upside down.

GregH 03-01-2019 08:59 AM

Quote:

Originally Posted by Marian Claire (Post 115871)
# 1. On my early, 1965, model there are two screws that have to be loosened to adjust the distributor. One is accessible from above like the late model. The other is accessible down low on the aft side of the distributor and is horizontal. You can see it in the attached pic.

Dan
S/V Marian Claire

http://www.moyermarineforum.com/foru...&pictureid=615

Sorry, cannot see any pic when clicking the link :(


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