OMC 2.3L - Stalls When Hot

[Jason Councilman]

My 2.3L OMC, which I thought was a "tune-up" issue is continuing. I've had the boat running, but got stranded on the lake Sunday afternoon about 300 yards from the dock. It took all but 10 minutes of running for it to die out.

Here's the situation... After the boat gets hot, it will begin mis-firing a little. After a couple more minutes, it dies out. Then it will not start.

If I run a jumper directly from the battery to the + side of the coil, the boat engine runs GREAT. No problems at all.

I've been told that this is a bad starter/key switch. So, I took the same jumper cable and jumped out the key switch. The engine will not run smooth, if it starts at all.

So, the only way I can get the engine to run well is be running the jumper from the battery to the coil.

Is it possible that the starter solenoid is bad and "acts up" after it's hot?

Is there something else I could be missing?

Please help... again.

 

[achris]

Re: OMC 2.3L - Stalls When Hot

I'm not completely familiar with the wiring setup of these engines, but if it's running a points ignition system, then the first thing I would be looking at is the resistance wire... between the key switch and the coil.

Chris........

 

[Boatin Bob]

Re: OMC 2.3L - Stalls When Hot

The coil has 2 circuits, first one feeds 12v (purple/black wire) from the solenoid when starting. After it starts it gets it's power from the alternator (purple/red resistor wire) via the resistor wire. You could have a flaky resistor wire or alternator or a connection between.

 

[achris]

Re: OMC 2.3L - Stalls When Hot

.... You could have a flaky resistor wire .....

Hey, that's what I said...

 

[JustJason]

Re: OMC 2.3L - Stalls When Hot

BoatinBob....
May I ask where you got that diagram? Is it just a scan or do you happen to have OMC man's on PDF?

 

[Boatin Bob]

Re: OMC 2.3L - Stalls When Hot

Hey, that's what I said...

Yes you did, but you said between the keyswitch and the coil and I just wanted to point out that it was actually between the alt and the coil

 

[Boatin Bob]

Re: OMC 2.3L - Stalls When Hot

BoatinBob....
May I ask where you got that diagram? Is it just a scan or do you happen to have OMC man's on PDF?

captJason...sent you a PM

 

[Jason Councilman]

Re: OMC 2.3L - Stalls When Hot

Is there a good method to test the resistor wire? Also, after starting (since it will start when cold), can I remove the positive wire from the battery and run the boat?

Thanks for help and diagrams!

 

[Boatin Bob]

Re: OMC 2.3L - Stalls When Hot

Easiest thing to do would be to check the voltage at the coil with a voltmeter after it first starts and then again when it starts to die to see if you have less.

 

[Jason Councilman]

Re: OMC 2.3L - Stalls When Hot

This morning (probably woke the neighbors up), I tested the voltage at the coil and coming off the alternator.

The alternator was stable at 13.5V (purple wire), even when the engine started to die.

The voltage at the coil, however, topped out at 11.5V when cold... Never ran without some mis-fires.

As it ran, the voltage would fluctuate. 11.5V then dropped down to 11.2 - once in a while it'd hit 10.8-10.9V When it was running rough (just before stalling) the voltage was low 11's high 10's. The last reading when it died was 9.5 at the coil. Again, the alt always had 13.5 coming out of it.

Now, with that information, I'm assuming the resistor wire is no good. Time for the silly questions... Do I need to split open the harness, find the splice ID'd in the diagram Bob provied and replace the purple/red wire with a 20 ga. wire from the hardware store? Not looking forward to jumping into the wrapped harness, but if that's all it needs...

Thanks,
Jason

 

[DJ]

Re: OMC 2.3L - Stalls When Hot

You can wire around the harness. However, you do need some type of resistance. Running direct voltage to the points will shorten their life-drastically.

 

[Jason Councilman]

Re: OMC 2.3L - Stalls When Hot

Understand wiring "outside" of the harness. And, thank you for explaining why the resistor wire is there... Keeps the points from burning up. More than I got from some of the guys at work.

But, the Owner's-Operator's Manual calls for, quote... "Ignition, Resistor Wire (20 Ga. Wire Only)" Unfortunately, I am not aware of any "special" resistor wire. Am I to assume standard 20 guage wire is acts as the resistor, or is there a specific type of wire needed?

Sorry ask such simple questions. Just not familiar enough with it to jump right in.

Thanks,
Jason

 

[Boatin Bob]

Re: OMC 2.3L - Stalls When Hot

Jason...that is a special wire with a fairly specific resistance. If you were to wire around it then you would need to replace it with an external ballast resistor. The actual OMC factory manual states if that wire goes bad then you need to replace the entire harness but we all know that isn't going to happen.

 

[DJ]

Re: OMC 2.3L - Stalls When Hot

There are many options to get the voltage down where you need it. If I read you post above, correctly, you stated that the engine started to run rough below 11.5V. Right?

There are resistance wires available (Radio Shack) for one, that determine voltage drop by length. You can also wire in a specific set resistor ro get where you need to be.

Realize that some resistors can generate a lot of heat. Wire is a better option.

Take a look at this thread also.

http://forums.iboats.com/showthread.php?t=272888

 

[Boatin Bob]

Re: OMC 2.3L - Stalls When Hot

You know that the coil should still be working fine when the voltage is down to 9 or 10 volts. I'm not so sure that you have a flaky resistor wire but possibly a bad coil that acts up when it gets hot.

 

[Jason Councilman]

Re: OMC 2.3L - Stalls When Hot

Thanks for the help. My OMC is in a 1990 Spectrum (bluefin) 1950. Is there a specific resistance I'm looking for? Looks like 2 ohms from the post DJ linked above.

Radio shack is just down the road. I will probably go there this a.m.

Bob, the coil is brand new. The exact same condition (stalls when hot) existed with the old coil. I've done a complete tune up, plus a coil. I've also jumped out the ignition switch to eliminate that from being the problem also. I've also been told that the ignition solenoid could be the problem, but it turns over every time.

Thanks for all the help guys!

 

[Boatin Bob]

Re: OMC 2.3L - Stalls When Hot

OK...didn't realize you had replaced the coil (didn't see it in any of your posts). The solenoid only comes into effect while starting not while running. The way it works is while starting the solenoid supplies a full 12v to the coil and once you let off on the key then the power comes from the alt through the resistor wire at a reduced voltage.

Another thing you could check easily is to see if the ESA module might be flaky and causing a problem. You can quickly unplug the 2 wire connector that feeds the module the next time your having the problem, see diag above, the purple and gray wires are in that plug, just remember not to leave it unplugged or you will have a harder time going from either gear into neutral.

 

[JustJason]

Re: OMC 2.3L - Stalls When Hot

You may want to check out napa as well.
they have a book that lists every ballast resistor for every motor (automotive)ever made.

 

[Jason Councilman]

Re: OMC 2.3L - Stalls When Hot

I finally got into running a ballast resistor (1.8 ohms) in line instead of the resistor wire. Here's where it stands. I ran an 18 gage wire in the splice to the resistor. From the resistor to the coil. The resistor got hot and the boat died out. While it was running, the voltage at the coil was 11.8V. I took the resistor wire out of the loop and the boat runs great (@ 13.5 volts). The boat got hot and would not die out or mis-fire, which is what started this post. The resistor wire is the culprit. But... What do I need to do to keep the ballast resistor from overheating?

Since I'm not an electrician, do I need to go down to a 20 Ga. wire or 22 Ga wire to keep the resistor from overheating? The original resistor wire was 20 gage.

Currently, the boat will run, but I don't want to burn the points up.

Any thoughts on whether or not a different gage wire will help.

Thanks for the help and have a safe Holiday on the water.

Jason

 

[mthieme]

Re: OMC 2.3L - Stalls When Hot

I just went through this last week with my 4.3 OMC.
It was the starter solenoid. It was supplying 5 volts instead of 12v to the coil.
I had whole 'nuther starter laying around, replaced it - viola - problem went away.
Unfortunately, being on the bottom of the engine and having no bilge except for the engine compartment itself, it has been submerged many times. (Damn bilge wouldn't stand upright for the auto switch to work - fixed that too while I was down there).
One other symptom I had was that when cranking, when I let off the key it started.