lights go out as A-4 stops

[capnward]

A couple of mysteries;
Yesterday before trying to start my usually trusty A-4 for the first time this spring, I tried removing spark plugs and shooting a little Marvel Oil into each cylinder. The idea was to lubricate the pistons to reduce wear when starting after they dried out over the winter. Plugs went back in, but the engine wouldn't start. Spark looked ok. Today I noticed the telltale red color of the oil coming out the bottom of the carb at the choke valve stem fitting. The carb had a lot of red-colored gas in it. No junk in it otherwise. I removed it and cleaned it, putting carb cleaner through the jets, and reinstalled. She started right up and ran fine after some smoky exhaust at first. I didn't think the Marvel would work its way into the carburetor and make the gasoline less flammable, but it did. I guess I put too much Marvel in the cylinders, and/or did it too soon before starting.
The other mystery, and the reason for the thread, is this:
After running for about a half-hour the engine suddenly lost some RPM and sounded different, as though some additional load was on it. It was in forward about 1200 rpm at the time, in the slip. I tried putting it in reverse for a while, in case something was in the prop, to maybe back it off. No change.
Then, after running the A-4 for an hour, I shut off the fuel upstream of the RACOR filter, and waited for it to run out of gas. I do this sometimes to keep the carb clean of fuel that may have dirt in it while it sits unused. It's not a problem as long as I remember to turn off power to the coil after the A4 shuts down. I had the blower running during this time, which is not usual, since I leave the engine compartment open and am there sniffing for gas. This time, when the engine shut down after a few minutes, the lights in the engine compartment and the blower shut down at the same time, but only for two seconds or so. Other electrical things may have stopped too, I don't know. This has never happened before. What could it be? Is there an alternator problem?
Appreciate any thoughts, thanks.

[msauntry]

I'd check for loose connections or suspect corrosion has gotten hold in the wires/connectors somewhere. Electric gremlins are hard to find, so you have to be thorough and persistent.

The drop in rpm might have been a fouling plug? Pull off the plug wires one at a time while its running and you should notice a drop every time. If one of the plugs is bad, you won't hear a change on that one.

The MMO can make its way down an intake valve from the combustion chamber to the carb. No harm done. I'd NOT run the carb dry though. That's the easiest way to get buildup of residue.

[capnward]

avoiding residue in carb

Thanks, I will check for bad connections. The plugs are due for replacement anyway, as are the plug wires. The plugs did seem a little fouled.
My rationale for running the carb dry has been this; the more gas in the carb when shut down, the more residue will settle in it as the gas sits in the carb and evaporates over time. If the gas runs out to be combusted, the residue that is suspended in the gasoline will go with it. I may be wrong, with an overactive imagination. I don't run it dry unless I suspect dirt in the gas, or unless it will be shut down for a long time. I can't say that leaving the carb full, as I usually do, has had any ill effects. But running it dry doesn't seem to make for more crud in the jets, in my experience. Maybe that's because I don't do it very often. Or maybe because the gas is usually clean, since I use non-ethanol fuel, avoid motoring in chop,and have two inline filters in addition to the RACOR. At any rate, I will stop running it dry, except maybe when laying up for the winter, and see if it makes a difference. Besides, it's easier that way.

[Mo]

The time to put oil in the top end it when you lay the boat up. I remove the carb and do this...and yes, I pour in lots of oil and it comes down the manifold where the carb attaches. I always dis assemble and clean my carb each fall as well. Personally, I make a point to turn the engine over a few times once a month just so that no rust ring will develop.

Start up day the carb goes back on and fire up the engine. It smokes pretty good for about 10-15 minutes (it takes that long to burn everything off) then it goes away. At that point I pull the plugs and clean them...good for the season.

Your electrical issue where all lights went out: Happened to me last year a just after motoring for 5 or 6 hrs. It was caused by corrosion on a plastic block where attaching large hot wire on alternator. I inadvertently hit it with my arm looking for cause and the lights flickered. 10 minute fix...took apart and cleaned up connections. That issue could be just about anywhere but that's a good place to start.

[JOHN COOKSON]

Mo, inadverntly or otherwise, came up with a good troubleshooting procedure.
Turn the blower on or the whatever else on and shake the wires around until you find the loose connection. Been there. Done it.

TRUE GRIT

[Mo]

Gurus just an email away.

John, the best thing about this forum is we have a guru in every department. I was at a place called Rogues Roost when that happened, and although I got it working, the first thing I did was email Neil Dutton ... got an email back from Neil within minutes. Sometimes having someone in your corner is the comfort that assures us that all is right in the world.

Was on the first evening of a 4 day weekend down the shore (I ended up changing the plastic block when I got home) but I knew what it was!

[JOHN COOKSON]

I Went One Step Further

When I discovered the clip that attached the wire to the alternator field coil (I don't know if this is the correct name) to the wire from coil + was corroded I cut it away and ran a new wire (with a fuse) from coil + then spliced, soldered, and heat shrunk the conection.

Yes, I know. If I ever have to remove the alternator I'll have to cut or unsolder the connection. So be it.

An intersting sidelight: Before I did this the alternator never seemed to be charging the battery correctly. After I got rid of the corroded clip everything seems to be normal as far as the battery discharge\charge cycle goes. I'm not an alternator expert so maybe it's my imagination here......

TRUE GRIT

[toddster]

I would certainly go over all of the wiring though... I've heard of those "lights going out" episodes being the symptom that immediately preceded the fire that destroyed the boat...

[Dave Neptune]

Shorts & grounds

capnward, most often bad connections and or corrosion work on the ground side of the current.
If you have any ground cables that are not looking good on the ends AND they have a dip in the cable give the cable a wiggle at the dip. I have seen all to often a ground cable with a "dip" in it corrode at the dip due to moisture accumulating over the YEARS. I have seen powder come out of a cable when split open to check. You will feel the flexability of the cover and not the wire, kinda like a soft spot.
Also take a good look at the key switch and the engines harness plug if still equipped with one. After these your chasing a short and good luck to that.

Dave Neptune

[capnward]

electrical problem worse than I thought

I have not done any troubleshooting like wiggling wires around when things are on, but I had better start soon. Dave's suggestion to look at ground connections would be a good place to start. Today when turning off the engine, not only did the knotmeter and the GPS go off for a few seconds, which I had started to ignore, but I also noticed the cabin light switch light on the breaker panel, which is always on, was off too. When I saw that, I tried the starter button, and nothing there either. So it seems that all electrical power is stopped for a few seconds when turning off the engine. Then it goes back on by itself. I will order a new ignition switch for a spare, as I suspect that is part of the problem. But how could a bad ignition switch turn off power to everything? And why would the shutdown be momentary? I have to find the problem before it becomes permanent.

[Dave Neptune]

Grounded?

capnward, what you are describing points at a bad connection or switch somewhere. You should trace and check the offending ignition, gage of lights ground paths first. You should also try to figure out just exactly what is powering up with the key switch!
The intermittent failures do indicate a power problem and those problems are usually on the ground side. Most connections on the power side are easy to give a wiggle and see corrosion, however the problem "USUALLY" is on the ground side and must be checked all the way to the batteries.

Dave Neptune

[tenders]

Did your boat once have a loran system? Those often came with large capacitors installed somewhere in the electrical system (not on the device itself) to filter out engine noise. When they die, odd things can happen, as we know occurs with dying coils, which are another type of capacitor. Though what is happening here really does not sound like anything coil-related.

But I would agree, first rule out or replace the moving part that changes position as this situation is presenting itself: the ignition switch.

How's the condition of your batteries?

You're going to need a cheap voltmeter, if you don't already have one onboard. Less than $15 at Harbor Freight, or Radio Shack.

[joe_db]

Engine loaded up = increased load on alternator.
Electrical devices quit when engine stops = no more battery in the circuit.

I would triple-check every bit of wiring between the the battery and engine.

[Mo]

Fwiw

Have a look at the connection "power" at the alternator as well. Mine has a plastic bushing / block there and had no lights / no power when shut down last year. Cleaned up connection and tightened it and all was well.

[capnward]

update: may have fixed it.

After studying the wiring compared to other ways of wiring Ignition switch, ammeter and alternator, I changed the connections so that the power to the ignition switch comes from the same post on the ammeter that is connected to the output of the alternator, instead of from the positive bus. The positive bus gets its power from the other post on the ammeter, which is connected to the starter at the post where the big wire from the battery switch connects.
This I think means that the ignition is now on a different circuit from all the other electrical things.
The engine started, ran for 20 minutes, and when I turned it off, the electricity stayed on. But I think it didn’t always shut down before when engine was turned off. Time will tell if I really fixed it. We’ll see if it works right once everything has been running for a while and is fully warmed up.
Ammeter readings seen unchanged. It only shows a little on the positive side when rpms get to a point where the alternator starts charging, and since batteries are usually charged, the ammeter needle goes back to just above center after a few minutes.
I still wonder what changed to create this phenomenon in the first place.
I also cleaned the connection at the output post on the alternator, maybe that was the fix. It didn’t look bad, but may have been just dirty enough. That is not a ground, however. There are other connections to ground I can inspect.