Exhaust hose integrity

[ccriders]

I am in the process of understanding why my spark plugs are fouled and read the sticky from Don Moyer on preseason trouble shooting. In that post he talks about the problem of internal collapse of the exhaust hose creating back pressure in the exhaust system, thereby fouling the spark plugs.
Today I removed the exhaust hose running from the water lift muffler to the exhaust through hull fitting. First I inspected it for cracks or other malformation, the I ran water through it in both directions and the I did a tap test listening at one end for a different sound. I used the plastic handle of a small screwdriver as a mallet. I found no cracks or deformations, the water ran freely in both directions, and the tap test produced a uniform sound for the entire length and circumference of the hose. So, is this and adequate test of the hose's integrity?

Also, I checked the coil per Mr Moyers sticky, did a compression test on each cylinder and installed new spark plugs. I'm now installing the electronic ignition upgrade.

My last step is to drain the carburetor and that is a problem, none of the carb diagrams indicate where the main carb plug is located. I could assume that it is located at the bottom most point on the carb, but I cannot see there and don't trust what I am feeling. Can someone point me to a pictorial/graphic diagram that identifies the main carb plug?

I'm doing all of this as the last time I was sailing, I had an engine shut down and my trouble shooting led me to suspect an ignition issue.

Your help is appreciated
John

[JOHN COOKSON]

A Quick Shot

Did you check to see if the choke is all the way open when you think it is?

TRUE GRIT

[Whippet]

carb

this should be plug you are after

[ccriders]

this should be plug you are after[ATTACH]8720[/ATTACH]

Thank you. I will try again tomorrow.
My what a nice clean engine you have. I wish I could get the rust off of mine.
John

[roadnsky]

...I'm doing all of this as the last time I was sailing, I had an engine shut down and my trouble shooting led me to suspect an ignition issue.

John-
Can you give us a better description of the shut down episode?
Was it sudden or a stumble, stumble, sorta death?
Be as specific as you can and the group can really help you.

I checked the coil per Mr Moyers sticky...

Can you tell us a little more how you did this please?

...did a compression test on each cylinder and installed new spark plugs

What were your compression numbers?

My last step is to drain the carburetor and that is a problem, none of the carb diagrams indicate where the main carb plug is located. I could assume that it is located at the bottom most point on the carb, but I cannot see there and don't trust what I am feeling. Can someone point me to a pictorial/graphic diagram that identifies the main carb plug?

See the attached diagram and pic.
You're looking for the MAIN PASSAGE PLUG.

Do you have the MMI Manual? If so, go to section/page 4-3 and you'll see better diagrams.
If not, its the FIRST thing you should order.

Give us as much info as you can and let's do this one step at a time...

[ccriders]

Roadnsky et. al.
Last time out was a very foggy day. Temp in the mid70s, water in the 60s. The engine compartment (Pearson 28-1) was literally dripping wet. Engine started normally but shut down while idling after sails hoisted. No stuttering or faltering, just stopped. Tried restarting, would crank but not start. I have had a history of points fouling, so while we were sailing I opened the distributor and cleaned the points. Tried restarting and the engine fired up for about 15 seconds and abruptly died and would not restart.
After we returned to the slip, I pulled the no 1 spark plug to see if it would fire. No spark at all. The plug's electrodes were quite fouled, no pitting or corrosion, but covered with black dry soot. I have been having an exhaust discharge of a black soot-like substance that floats on the water. It is emitted most often when increasing rpms and/or first starting.
So, I'm figuring that the carb is too rich creating carbon in the cylinders and that I need to do two things - fix the ignition by going electronic and lean out the carb.
Earlier this year I did the muriatic acid bath, cleaned and tested the thermostat, replaced the temp sending unit and installed a new temp gauge. I get a healthy clean cooling water flow with some light grey smoke until the engine warms up to operating temp.
After ordering the EI I saw Mr. Moyer's sticky on spring commissioning, which led me to inspecting the exhaust hose as described above. I pulled all of the spark plugs, pulled the coil lead from the distributor and place it about 3/4 inch from the head and cranked the engine for about 10 seconds and observed a healthy blueish spark. Compression numbers are: 1 - 65, 2 & 3 - 85, 4. - 90. I could probably get more reliable numbers with a helper. Holding the gauge on the plug aperture and pushing the start button is a big stretch, even for my ape like arms. But there is compression, there is spark from the coil and now there are new plugs gapped at .035. Also there is now the new EI. I've not fired it up yet as I want to verify the the coil is 3 or more ohms internal resistance, which I will do shortly.
So I believe the last step is to verify clean fuel in the carb. When I removed the flame arrestor I found it to be quite dirty. I can't tell yet if it is oily or sooty. Will investigate that today. It is interesting to see the difference between the photo posted above and your diagram. I have the adjustable main jet, so will remove it, which will give me the opportunity to adjust it so it can be turned without pliers.
I would appreciate your comments and observations especially if you think my test procedures for the exhaust hose were sufficient, and if my diagnostics process is sufficient.
Thanks,
John

[ccriders]

p.s.
I do have the manual, but was confused by the terms "adjustable main jet" and "main passage plug". It seems my Series 68 carb has been fitted with the adjustable main jet as illustrated for the Series 61 model carb.
Also, I hope I didn't put too many red herrings in my above description of my efforts thus far.
John

[roadnsky]

It is interesting to see the difference between the photo posted above and your diagram. I have the adjustable main jet, so will remove it, which will give me the opportunity to adjust it so it can be turned without pliers.

John-
The Adjustable Main Jet replaces the Main Jet Plug.
It has a lock nut (5/16) that you loosen which will make turning the T-Handle much easier.
You should NOT have to use pliers to turn it.
"...turn the "T" handle on the end of the needle IN until you feel it make contact with the fixed jet. Then back the needle out approximately 1 and 1/2 turns. This should be a good initial setting. After warming up the engine, and at your favorite cruising power setting, turn the "T" handle in and out until you find the best RPM."

NOTE: You will find quite a large zone in the adjustment process where the engine performance will not noticeably change as the "T" handle is turned one way or the other. By turning the "T" handle in (clockwise) until a definite decrease in engine performance is noted, and then backing it out just until power is restored, the best fuel economy will be achieved.

[ccriders]

Ah, so the adjustable main jet is not the primary lean/rich adjustment. Is that right?
John

[hanleyclifford]

Ah, so the adjustable main jet is not the primary lean/rich adjustment. Is that right?
John

No. The adjustable main jet sets the air/fuel ratio for when the engine is at cruise rpm whereas the idle adjusting screw sets the mixture in the idle fuel circuit. Once the engine is at cruise rpm the idle screw has little impact on total mixture.

[roadnsky]

No. The adjustable main jet sets the air/fuel ratio for when the engine is at cruise rpm whereas the idle adjusting screw sets the mixture in the idle fuel circuit. Once the engine is at cruise rpm the idle screw has little impact on total mixture.

As Hanley said, get the idle mixture right first and then set the Adjustable Jet at cruise RPM.

A good starting point for the idle mixture screw is 1½ turns out from the seat.
Remember that the idle adjustment (on top of the carburetor with a screw driver slot) adjusts the air portion of the mixture, so turning the adjustment in makes the mixture richer, and backing it out makes it leaner.

[ccriders]

Follow-up

Well, first of all a hearty thank you for your responses. I have an operating engine.
Following leads found here, I learned:
1. How to test the resistance and internal integrity of a coil, learned that the one installed might have damaged my new EI module and that an older coil I had replaced was healthy and of the correct resistance (4 ohms).
2. I think I have discovered why my adjustable main jet was so hard to turn. With the packing nut backed of just so it does not require a tool to turn, it leaks. So right now it is all tightened up until I can determine what kind of packing material is used in the valves and where I can get it. Any help there?
3. Clean spark plugs and the increased dwell of EI makes for a really strong start. So if anyone has to crank their engine for more than a few seconds, take a close look at your ignition system.
4. Don't tolerate smoke and don't wait until you're spitting out soot to find and fix the root cause.
I plan to remove and inspect the spark plugs once I get about 25 hours on them. I'm sure there is plenty of built up carbon to work out of the system.
The only open item is how to repair the adjustable main jet.
Oh, and another LL - you do no good babying your engine, never getting much over idle and shutting it down as soon as the sails are up. It needs to work a little (frequently?) before going to rest.
Thanks again
John

[roadnsky]

Check that the washer is there and in good shape.
If the larger nut gets cranked down too hard the washer can get "squeezed" out and that could be your leak point.

[ccriders]

Check that the washer is there and in good shape.
If the larger nut gets cranked down too hard the washer can get "squeezed" out and that could be your leak point.

I did. There were two, one fabric and one metal. The fabric was on the inside of the metal. When I removed the jet completely there was only a small bit of packing material stuck around the threads of the jet. Not enough to identify what kind of material it was made from. Do you think I could use a waxed heavy whipping twine as a packing material? Or maybe cut a thread of gasket material?
Thanks,
John