Engine idling fine then shut off like turning key off, will not restart

[Bryan Howell]

Bryan-
That sentence says a lot IMHO...
If it were my vessel, I would want to KNOW why an issue was resolved.

I took a bit of time and read thru your past threads and posts to get a better feel for the history leading to where you are today...

http://www.moyermarineforum.com/forums/showthread.php?t=10183

No resolution

http://www.moyermarineforum.com/forums/showthread.php?t=10263

Scavenge Tube & Carb issue

http://www.moyermarineforum.com/forums/showthread.php?t=10493

Resolution? No answer to carb question in POST #15

Something that really stands out, that I agree we should resolve BEFORE moving on to the next "step"... (IGNITION) is to assure that we can eliminate fuel.

We need Fuel, Spark and Compression to run our beasts.

Here is one of my favorite Don troubleshooting methods...
“Have you performed any maintenance on the engine recently?”
It always provides me with a bit of tension releasing amusement when I'm told: "Why yes, I just replaced the plugs, points, and condenser last week, - so I know that the problem can't be in that area!" (Not necessarily so)! Whenever you experience problems after performing maintenance, always go back over every step of your work to see if you overlooked something.
This is one of the most fertile places to find reasons for intermittent shutdowns.

Attached is a document with some more of Don's troubleshooting wisdom.

Thanks for the reply, I really appreciate it. Well, it wasn't totally magic. I discovered a vacuum line that was was a bit lose which once tightened up seemed to resolve the surging issue. That and giving the plugs a little cleaning. This after removing, cleaning and reinstalling the carb, so I fully understand to check what you have just done, you probably screwed up or forgot something.

I want to eliminate ignition before looking at fule as the issue, and not arbitrarily. I think maybe what is missing here is the fact that the engine, minus the surging issue, which has been resolved, was running fine, even with the surge, after 18 months of time, money, sweat and cursing with fuel issues. All done. Successfully. Since then, no new maintenance, no new fuel, no new anything except the pleasure of having an engine that actually ran great since I replaced the tank and everything fuel related and totally cleaned my new carb. Runs great, come in, shut down, tie the boat up. Come back 2 days later, start it, idle it and have it just stop dead after a couple of minutes. In my experience, fuel issues do not lead to a clean, abrupt stop. Not on my boat, not in any of my cars, not even on my lawn tractor. Lose rpm, power, sputter, etc, etc. Not an instantaneous complete shutdown. Literally like turning off the key.

If you do not have fuel, you have no combustion, I get that, really. But, at the same time, if you have no fire, or inadequate fire, you get no combustion, either. I guess I understand why everyone wants to start at fuel, it is easier and more common, but I have been at fuel for 18 months. I have been living the fuel issue for a long time and finally resolved it with the new tank, etc. Sure it was a carb issue because it sucked up gunk from a rusty tank, as did the filters, and the tank allowed water seepage. This is a road very well traveled by me. And a motor that won't catch, even with no fuel line attached, when blasted with starting ether, tells me I have a fire issue. I had a terrible addiction to British sports cars in the 70s and early 80s, so I have certainly spent some time squirting ether to figure out fuel or ignition. Or both...... The sweet mysteries of Weber carbs. So I have, based upon my diagnostic efforts to date, come to the belief, perhaps erroneously, that altho I have some spark, I do not have nearly enough. I know what spark in a properly working ignition system should look like, and it is a nice bright blue white zap, not a weak flicker. Which then takes me into my weak spot, ignitions.

I gave up tuning my own cars when I tried to hook my timing light up to a car that had a "ëlectronic ignition module" on it. All my previous cars had points and condenser and I knew what I was doing (sort of). So all of that said, I still may be wrong. I ordered a new distributor cap, (mine looks funky) plug wire set, and plugs from Moyer, will get them Monday, put them on Tuesday. We will see what that does. As to the Ignitor electronic system I have, it is just a box and a bunch of wires to me, no clue. Do they just "GO BAD"? Seems like they would either work or not work. But again, I have no clue. So this is the area I really need some help with.

I have read virtually everything Don Moyer has ever written, I think...


I really do value the help given in these forums, the experience behind that help, and the spirit in which it is all shared. I just need someone to give me some thoughts on the ignition system, I really do understand the fuel system far better than I ever wanted to. To the forum, ""help me, Obiwan"". But just for now can we pretend that I DO NOT have a fuel problem? Please. If I turn out to be wrong I will gladly acxknowledge same and take public forum shaming.

[Sam]

Some good advice has been given here I am going to highlight something specific that has bee mentioned previously. Separate the "boat part" from the "engine part" and read Don's "non -start checklist". I have resolved non-starting [ & engine stopping] twice, once on my boat [points] and a friends boat [EI] using a jumper wire from the coil to by pass the ignition switch. In both cases the switch was faulty - mine was dead and on my friends boat it was "intermittent". Maybe your switch is weak, faulty or intermittent. It is however a small expense and an easy test, maybe a little awkward to work on.

[JOHN COOKSON]

Bryan
Don't loose sleep over your no start engine. When we get done you will have fuel and spark delivered to the cylinders. Relax and enjoy the ride. (easy for me to say)
IMO it is best to do troubleshooting in an orderly manner rather than say "it could be this or that" before we find what is causing the problem. Once we can localize the problem(s) we will dill down bit with more diagnostics and figure out the fix will be.

TRUE GRIT

[Dave Neptune]

Having an EI and a weak spark is not good. The spark should be snappy and blue. I would check the "RUNNING" voltages at the coil to confirm good voltage. Then I would remove the cap and rotor for inspection, checking for cracks and "carbon trails" inside the cap. Another resistance could be a poor coil wire and/or plug wires. When the engine was converted to EI were all the wires, cap and rotor replaced? While inside the distributor check and lube the c-advance too.

The surging sounds more like fuel and a weak spark could exacerbate that.

A vac leak usually won't surge, but it is air and does influence the fuel mix.

Dave Neptune

[Bryan Howell]

Some good advice has been given here I am going to highlight something specific that has bee mentioned previously. Separate the "boat part" from the "engine part" and read Don's "non -start checklist". I have resolved non-starting [ & engine stopping] twice, once on my boat [points] and a friends boat [EI] using a jumper wire from the coil to by pass the ignition switch. In both cases the switch was faulty - mine was dead and on my friends boat it was "intermittent". Maybe your switch is weak, faulty or intermittent. It is however a small expense and an easy test, maybe a little awkward to work on.

I thought about the possibility of the switch, even tho it seems to be functioning correctly, and was replaced last year. Plan on replacing the dist cap, all plug and coil wires, and new plugs probably Tuesday (ordered from Moyer for delivery Monday) Hope that fixes it! If not I'll try bypassing the switch. Thanks for the help!

[Bryan Howell]

Bryan
Don't loose sleep over your no start engine. When we get done you will have fuel and spark delivered to the cylinders. Relax and enjoy the ride. (easy for me to say)
IMO it is best to do troubleshooting in an orderly manner rather than say "it could be this or that" before we find what is causing the problem. Once we can localize the problem(s) we will dill down bit with more diagnostics and figure out the fix will be.

TRUE GRIT

Heh John, glad you are chiming in. Agree 100% on troubleshooting one area first, I guess my issue has just been everyone seems to insist that I start with fule, and I am far more inclined to start with ignition. With replacing dist cap, plug wires, coil wire and new plugs that will be a pretty good start. But as I have mentioned, as to the EI I am pretty much clueless. Thanks for getting involved!

[Bryan Howell]

Having an EI and a weak spark is not good. The spark should be snappy and blue. I would check the "RUNNING" voltages at the coil to confirm good voltage. Then I would remove the cap and rotor for inspection, checking for cracks and "carbon trails" inside the cap. Another resistance could be a poor coil wire and/or plug wires. When the engine was converted to EI were all the wires, cap and rotor replaced? While inside the distributor check and lube the c-advance too.

The surging sounds more like fuel and a weak spark could exacerbate that.

A vac leak usually won't surge, but it is air and does influence the fuel mix.

Dave Neptune

My thoughts exactly, Dave, and the spark I had was pretty anemic. Hopefully the dist cap and wires/new plugs will fix me up. I have been leery of my dist cap for a while, it just seems to not be in good shape, screws are difficult to turn, so I am really hoping it is that. Should know Tuesday...

In going thru the Moyer manual something kind of caught my eye, the oil pressure safety switch. If that switch was defective I assume it would cut power to the ignition and shut down the engine? Is it possible that could be my problem? The shutdown was so clean and abrupt, just like turning the switch off, I am just wondering. Also, the surging seemed to stop after I tightened the one vacuum line but also after taking the oil filler tube cap off and putting my hand over it. That was the "magical" part I was referring to earlier, I frankly felt it was just coincidence. Now I am wondering... What do you think?

[tenders]

The OPSS controls nothing more than power to the fuel pump. If there isn't oil pressure, ie if (1) the engine won't start or shuts down or (2) there isn't any oil, it turns off the fuel pump so (1) the carb doesn't flood and fill the engine room with gas or (2) the engine doesn't seize catastrophically. Although it probably will anyway.

So this means the engine usually is asked to start up without any power to the fuel pump for several seconds, relying on residual gas in the carb bowl to start the engine. Once the oil pressure builds a bit, the fuel pump kicks in and catches up. If the OPSS connections are loose, or the switch has failed, the engine will literally run out of gas.

This is easy to see, and diagnose if there's something wrong, with an inexpensive inline fuel pressure gauge. (And potentially easier to see with a more expensive sort of fuel pressure gauge, like some of the white-glove guys around here have.)

[Bryan Howell]

The OPSS controls nothing more than power to the fuel pump. If there isn't oil pressure, ie if (1) the engine won't start or shuts down or (2) there isn't any oil, it turns off the fuel pump so (1) the carb doesn't flood and fill the engine room with gas or (2) the engine doesn't seize catastrophically. Although it probably will anyway.

So this means the engine usually is asked to start up without any power to the fuel pump for several seconds, relying on residual gas in the carb bowl to start the engine. Once the oil pressure builds a bit, the fuel pump kicks in and catches up. If the OPSS connections are loose, or the switch has failed, the engine will literally run out of gas.

This is easy to see, and diagnose if there's something wrong, with an inexpensive inline fuel pressure gauge. (And potentially easier to see with a more expensive sort of fuel pressure gauge, like some of the white-glove guys around here have.)

I have a relatively inexpensive one, which I will be using if my other efforts fail. Thanks.

[JOHN COOKSON]

In going thru the Moyer manual something kind of caught my eye, the oil pressure safety switch. If that switch was defective I assume it would cut power to the ignition and shut down the engine? Is it possible that could be my problem?

No.
The OPSS cuts power to the fuel pump when it is open or is defective. It gets power from the ignition system and when closed (oil pressure up) transmits electricity to the fuel pump

TRUE GRIT

[Bryan Howell]

No.
The OPSS cuts power to the fuel pump when it is open or is defective. It gets power from the ignition system and when closed (oil pressure up) transmits electricity to the fuel pump

TRUE GRIT

Ok, so the shut down would be a fuel starvation type, not the abrupt cutoff I had, I guess. Still worth checking, agree?

[JOHN COOKSON]

Ok, so the shut down would be a fuel starvation type, not the abrupt cutoff I had, I guess. Still worth checking, agree?

Yes.
In my experience some fuel related shutdowns are abrupt.
My last OPSS caused shutdown I was sure was an ignition problem until I did some diagnostics.

TRUE GRIT

[roadnsky]

...Plan on replacing the dist cap, all plug and coil wires, and new plugs probably Tuesday (ordered from Moyer for delivery Monday) Hope that fixes it!

It's been 10 days... Any update?

[roadnsky]

Bryan-
It's been over a month...
Can you update us please?