Down the fuel rabbit hole

[Crazer]

Bought gas from the marina fuel dock. Serious mistake. It ran for about fifteen minutes and then died as we were coming out of the channel. Managed to limp back with the engine running very lean. I get back, the boat sits for a few weeks and when I try to restart it won't run at all. Now I'm down the fuel rabbit hole again. Luckily, I eff up boats for a living these days instead of just effing up my own boat in my free time so, feeling confident, off I go troubleshooting. A week and a half later the thing still won't run so now I am humbling requesting help.

What we know:
Fuel pump runs and pumps fuel
Clean fuel is getting to the carb-filters changed and I'm running off a jerry can
Carb has been cleaned-carb cleaner sprayed into all orifices until it came out all the other orifices
I have not rebuilt the carb
Engine runs on starter fluid sprayed into the flame arrestor

My first thought is that maybe the coil has gone bad and I'm getting a weak spark (just enough to fire on starter fluid but not on fuel)

I did check for spark, and it seemed weak but I may not have been grounding the plug well enough. Does my theory seem possible?

My basis for this is that I foolishly left the ignition key on for an unknown number of hours so maybe that damaged the coil.

My confidence in my carb cleaning is very low but I was thorough and I feel like it would be doing something if that was the issue since fuel is definitely getting there.

And because it will get asked: YES the fuel was bad. It's cloudy, with lots of debris and stinks of old gasoline. There was a lot of crud in the carb when I took it apart. Some water, too.

[sastanley]

Crazer..please excuse the "direct" questions...

With the 'unknown' time you left the ignition switch on, we now have two issues to deal with. You have to decide which one to deal with first. You said the fuel is now good, so let's deal with the leftovers in the carb since your confidence there is low.

Did you remove the carb and actually clean all orifices? (A clean is not the same as a rebuild..IMO a good cleaning is sufficient 90% of the time, which might only require a new manifold flange gasket if it is damaged during carb removal.. )

Your guess is as good as mine here. If the engine runs on engine crack (starter fluid), I'd eliminate the ignition at this time, or at least set it to the side. Once you fix the fuel issue and it runs on something besides starter fluid...and maybe it runs for 45-60 minutes and quits...then we move to the coil.

My point is, starter fluid only I think means fuel delivery issue. If you've been messing with the carb, confirm choke closes 100% with the cable, and remove the carb if necessary to clean out the idle jets and main jet with the main jet plug removed at the bottom of the bowl for proper access to the main jet. "Runs on starter fluid" to me leans in the direction of maybe you missed an orifice.

My $0.02.

[ndutton]

There are multiple problems now:

Fuel
Fuel might be getting to the carb but it's not getting through the carb to the intake manifold and beyond. The starting fluid test pretty much confirms this is still a fuel problem.

Coil
The ignition-on episode is not a guaranty the coil is done but for sure the coil can no longer be trusted. With points ignition the statistical risk of a coil meltdown with the ignition accidentally left on is about 39% (EI is closer to 70%) but anecdotally it's more like 95%. I think this is because the engine typically stops on one of four compression strokes. It's time to replace the coil at least on principle.

edit:
Shawn types faster than me

[sastanley]

I was probably editing and babbling, but we are on the same page. I am off looking for the carb diagram we all talked about a couple weeks ago.. I'll add it when I find it over in the schematic section.

edit - I think both of these diagrams will prove useful..particularly the service info PDF to make sure everything is clean.. http://www.moyermarine.com/forums/showthread.php?t=7085

[JOHN COOKSON]

Do the spark plugs and the cylinders smell of unburned gasoline after a period of no start cranking?
Is fuel pooling in the throat of the carburetor after a period of no start cranking?
Have you been keeping the engine raw cooling water inlet valve closed while no start cranking?

TRUE GRIT

Pull the center wire out of the distributor, and hold it near the engine, while cranking. A 1/2-3/4" blue white spark is good. As noted even if the coil passes this test it should be considered to be compromised but it might be enough to get the engine started.

[edwardc]

You said you sprayed out all the carb orifaces, but with today's wimpy carb cleaners, that's often not enough.. You must physically clear each oriface with a small wire. The center wire removed from a bread tie works well for this.

[Crazer]

Thanks for all the replies. I have a carb kit order, and the tip about the small wire is very helpful. Will tear her down again and report back.

Edited to add: Yes, the seacock has been closed this whole time.

[capnward]

Yes, run a small wire around in the jets, particularly the idle jet. Shooting carburetor cleaner through it is not enough, in my experience. Take out the tiny idle jet, hold it up to the light, and look for an obstruction, before and after you run a wire from a wire brush around in it. When you get crud in your carb, the idle jet seems to be the first thing clogged, and even if you can shoot cleaner through it, some microscopic piece of crud can remain. It can make a big difference in running, especially at low rpm. Run a wire in the small idle ports in the throat, too.
Anecdote: I have accidentally left the ignition on overnight, but to no ill effect that I could tell, and I have EI. Maybe I'm one of the lucky 5%. I have replaced the coil since then, but not sure I needed to. It was working when I removed it. I keep it as a spare, maybe a mistake.

[JOHN COOKSON]

Originally Posted by Crazer

My basis for this is that I foolishly left the ignition key on for an unknown number of hours so maybe that damaged the coil.
.

I have a habit on my boat. The key is never in the slot unless the engine is being cranked or is running. If I know that I will need to turn the engine again soon, as in trouble shooting, I take the key out of the slot and lay it on the bench.

TRUE GRIT

[Wrsteinesq]

Would it be possible to use some form of a simple timer circuit to cut power to the coil after some appropriate time interval if the engine wasn't running? I assume the OPSS would be the trigger. Turning the key 'on' starts the clock; and if the OPSS hasn't closed after, say, 30 seconds, power to the coil is cut. If it takes more than 30 seconds to start, just turn the key 'off,' and when it's turned back on again, the clock starts again. Just a thought.

[joe_db]

I have a loud buzzer triggered by low oil pressure or high water temps. No way will anyone be able to stand listening to that long enough to burn a coil out

[ndutton]

Originally Posted by Wrsteinesq

Would it be possible to use some form of a simple timer circuit to cut power to the coil after some appropriate time interval if the engine wasn't running?

It's cool that you're thinking about a provision to protect against this recurring problem, the problem being absentmindedness (happens to all of us, doesn't it?). As Joe points out, Moyer Marine already offers two products that achieve the same goal as your proposal:
http://www.moyermarine.com/cgi-bin/s...ey=KTAS_01_460
http://www.moyermarine.com/cgi-bin/s...ey=KTAS_01_191

[Crazer]

Found my way out of the rabbit hole. Cleaned out the jets with a wire as suggested and sprayed out the main jet and passages. Also replaced the bowl gasket as the old one was looking a little ratty after all this. Reassembled and the old girl fired right up. Suspect there was crud blocking the main jet passage because there was some white precipitate at the bottom of the bowl.

I've managed to acquire a second A4, wrapped in rather a pretty boat (a Grampian Classic 31 if anyone has ever heard of it) so I'm sure my adventures will continue. The "new" one is a 1965 original so points, mechanical fuel pump etc. Yippee!

[sastanley]

OK, crazer..nice work. let's see how it goes!

Don't get too sidetracked with the new motor attached to the 'new' boat while you still have a few weeks on the "other" boat!

I don't know the differences, but Paul & Trina (PT26) here with me on the Chesapeake have extensive experience running an A-4 in their Grampian 26!