Ignition Switch Problem – OR???

Ignition Switch Problem – OR???

Cold starting engines with salon keys it usually (75% of the time) is impossible to get port motor to idle down below 1500 rpm without it beginning to badly stumble; below 1000 rpm to instantly quit. Engine usually does work better once completely warm and when warm will often idle down OK after many minutes of stumbling during warm up. Always runs fine above 1500 rpm when cold or warm. If run for a while on cruise and still warm salon key port engine restart offers no problem. Other 25% of time at cold start the port idles down with no issue while using salon key. Salon key start on stbd engine is never a problem. On fly bridge keys both engines start and idle down with no problem; cold or warm.

Salon port key engine starter failing internally?? Or, just follow wires and clean all terminals?? I like to start both engines when at salon controls so I can listen closely during warm up. I 99.9% of time then shut them down and restart from bridge controls.

Any way to “test” starter switch to learn if it is breaking down internally?

Thanks, Art

Happy Boater Daze!!

Art, to my way of thinking it should not matter where you start them from unless diesel and the glow plugs are not being activated from one station???

Art said:

Ignition Switch Problem – OR???

Cold starting engines with salon keys it usually (75% of the time) is impossible to get port motor to idle down below 1500 rpm without it beginning to badly stumble; below 1000 rpm to instantly quit. Engine usually does work better once completely warm and when warm will often idle down OK after many minutes of stumbling during warm up. Always runs fine above 1500 rpm when cold or warm. If run for a while on cruise and still warm salon key port engine restart offers no problem. Other 25% of time at cold start the port idles down with no issue while using salon key. Salon key start on stbd engine is never a problem. On fly bridge keys both engines start and idle down with no problem; cold or warm.

Salon port key engine starter failing internally?? Or, just follow wires and clean all terminals?? I like to start both engines when at salon controls so I can listen closely during warm up. I 99.9% of time then shut them down and restart from bridge controls.

Any way to “test” starter switch to learn if it is breaking down internally?

Thanks, Art

Happy Boater Daze!!

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I would rig a jumper between the hot lead and the IGN pole....if it is starting OK then just add the jumper over to the IGN lead and see if she settles out. Does depend on the switch but many are the same...OFF-IGN-Start.

It might be a complete waste of time because I haven't though your problem through...but that would eliminate the IGN portion of the key switch as a problem....you can do the same at the engine end of things if you prefer...that way you don't have to fiddle with juggling the key switch.

LaBomba said:

Art, to my way of thinking it should not matter where you start them from unless diesel and the glow plugs are not being activated from one station???

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Gee, Allan - I should have mentioned... 1977 Mercruiser 350 cid / 255 hp gasoline engines with Rochester Quadrajet carbs and heat activated "spring" chokes.

Good running old school rebuilt gasers - basically bullet proof!!

Art said:

Gee, Allan - I should have mentioned... 1977 Mercruiser 350 cid / 255 hp gasoline engines with Rochester Quadrajet carbs and heat activated "spring" chokes.

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Shhhh...now you'll get blasted for having gas engines AND a flying bridge....

psneeld said:

I would rig a jumper between the hot lead and the IGN pole....if it is starting OK then just add the jumper over to the IGN lead and see if she settles out. Does depend on the switch but many are the same...OFF-IGN-Start.

It might be a complete waste of time because I haven't though your problem through...but that would eliminate the IGN portion of the key switch as a problem....you can do the same at the engine end of things if you prefer...that way you don't have to fiddle with juggling the key switch.

Click to expand...

Thanks - I will play "test-a-rama" when opportunity presents itself.

psneeld said:

Shhhh...now you'll get blasted for having gas engines AND a flying bridge....

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I Can Take IT!!! :lol:

Art said:

Gee, Allan - I should have mentioned... 1977 Mercruiser 350 cid / 255 hp gasoline engines with Rochester Quadrajet carbs and heat activated "spring" chokes.

Good running old school rebuilt gasers - basically bullet proof!!

Click to expand...

In which case I agree with psneeld that I would look at the ignition switch or it's connections as you may not be getting full voltage to the distributor and/or coil.

Don't tell anyone but I have a flybridge as well, and I happen to like it!

Put a voltmeter on engine coil positive and read volts with the different keys. If different, gots to walk through the circuit with the meter and find where there is a volt drop. Keyswitch a prime culprit, also any harness plugs in the system.

Replacement ignition switches are inexpensive (under $20) and easy to change out. It might be an easy resolution. If not, you now have a spare ignition switch.

Thank you all for quick input.

I will eventually run a diag on it. As Ski says... and I agree - "Key switch a prime culprit." I had one on a twin screw, dual control station go screwy some years ago. Its effect was different on the engine it controlled; also causing intermittent disturbances.

I wonder - can ignition switch be rebuilt?? I'd like to keep same key working all four ignitions.

Happy Engine Starten Daze! - Art

Take the replacement to a locksmith and let him reset the pins to match the other three. Cheaper than you'd expect, assuming the same style key of course.

When you have twins, the troubleshooting gets simpler. Swap switches port to starboard and see if the problem moves. This is a 20 minute job with good access. Just don't drop those contact screws into the never-find-it-again zone!

Had the same engines in a 30' Tolly. Stumbling problem for me was a sticky choke. A shot of WD and it was solved.

I had a single exactly like you in my Bayliner 2550. It really sounds like the choke. Are you positive it is not an electric choke? I had the coil spring chokes also. If it was a bad switch it should not matter hit or cold motor. The switch doesn't get hot or cold. If it is providing power then I would look at choke and then ignition components.
Jeff

ancora said:

Had the same engines in a 30' Tolly. Stumbling problem for me was a sticky choke. A shot of WD and it was solved.

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Jbear said:

I had a single exactly like you in my Bayliner 2550. It really sounds like the choke. Are you positive it is not an electric choke? I had the coil spring chokes also. If it was a bad switch it should not matter hit or cold motor. The switch doesn't get hot or cold. If it is providing power then I would look at choke and then ignition components.
Jeff

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Thanks guys - Spring choke is activated by temp rise of engine... it works well - I keep all moving portions of carb and choke lubed and have watched it during warm-up. Don't forget what I intoned in op. Engine only stumbles and quits when using salon ignition switch... but... does not stumble or quit when using Fly Bridge ignition switch. I'm betting on either faulty switch or faulty connection some where to the engine. Eventually I'll perform one or more of the tests suggested in this thread.

Check the easy stuff first, clean/tighten screws and give the wires at the connecters a tug, then if no difference swap the two switches.

I must be simple if the FB switch makes the engine run normal.