QuickSilver Dual Controls - Shift Interuppter Issue ???

[achris]

Worth looking at an OMC product, liquid neoprene. Coat all the exposed electrical metal parts with that and no more corrosion.

 

[Bondo]

Ayuh,..... I've been usin' Fluid Film on such things for awhile now, sprayed,...

Don't clean anything, but seals out the O2 to stop corrosion,...

Not as messy as axle grease on the battery terminals,...

 

[achris]

Ayuh,..... I've been usin' Fluid Film on such things for awhile now, sprayed,...

Don't clean anything, but seals out the O2 to stop corrosion,...

Not as messy as axle grease on the battery terminals,...

Merc's original formula of Corrosion Guard was like that, but they changed it a while ago and it's not nearly as good.

 

[tpenfield]

Oooppss . . . it did it again :facepalm:

coming back from a day on the water going 3600 RPM 42 mph, as I touched the starboard throttle lever, the engine cut-out for a split second . . . did it a couple of times. So, I think that I am back looking at the throttles.

Since I want new ones anyway, I'll just put it on the list and maybe check replace the kill switches as well.

 

[GA_Boater]

I don't recall - Have you looked at the wiring inside the control?

Do Bravos have shift interrupts? I never owned any motor as new as yours.

EDIT - Guess I should pay attention to the thread title! :doh:

 

[tpenfield]

I don't recall - Have you looked at the wiring inside the control?

Do Bravos have shift interrupts? I never owned any motor as new as yours.

EDIT - Guess I should pay attention to the thread title! :doh:

It is a fair question, as I am not sure if the Bravo's need shift interrupt. I think someone in this thread indicated that they do not need shift interrupt. However, I would think that the control has the mechanism since it could be used for Alpha's as well. Just not sure if it is hooked up or not.

With the season (for me) close to being over, I will take things apart during the off season.

It seems to only happen when I am throttled up to the 3000-4000 RPM range. If I run in the 2500-3000 RPM range, I have not noticed it.

 

[achris]

Shift interrupt switch is mounted on the shift plate on the engine, but only for Alpha drives. Bravo drives don't have them. The only thing electrical inside the control boxes should be the neutral safety switch, and that only operates in the START circuit. Once the engine is running it doesn't matter what that switch does, open, closed, shorted to ground, it's not going to make one bit of difference.

This has got me curious. If the engine is being shutdown electrically, how is that possible if there's nothing connected to the electrical system inside the control box? Something else is going on. :noidea:

Chris. ...

 

[GA_Boater]

Let's switch ends. On the engine when the throttle is at the approximate setting for 3-4000 RPM, are any ignition wires being rubbed by the throttle cable or throttle linkage?

I guess you could look under the dash for the same, but the moving stuff is back on the motor.

This is a puzzlement!

 

[achris]

Let's switch ends. On the engine when the throttle is at the approximate setting for 3-4000 RPM, are any ignition wires being rubbed by the throttle cable or throttle linkage?

My thoughts precisely...

 

[tpenfield]

Good idea guys . . . I will go through the linkages at the engine as well at at the helm.

 

[tpenfield]

Quick Update:

I took a look in the engine compartment and did not see any wiring near the throttle or shift linkages. So I tootchesk a look at the wiring under the area of the throttles.

There are the kill switches . . .


and there are the throttles . . .



I am wondering if the white and white/red wires are for the shift interrupt :noidea:

Anyway, my thoughts were that the connections to the kill switches might be a bit corroded, so I worked those a little bit. Time will tell if the problem persists.

 

[GA_Boater]

Those white/red wires are probably connected to the neutral switches. In the prior pic of the ignition switches, it looks like a white/red wire is connected, which would make sense. Do you have a wiring diagram to verify?

But neutral safety switches only kill the starter, not the ignition.

 

[mr300z87]

Hi Ted, First let me say that intermittent problems like this are really frustrating to diagnose as you know. Since you have Bravo drives there is no shift interrupt switch as they are used only on Alpha drives to assist engaging and disengaging the clutch dogs in the shift mechanism. I think this has been mentioned already in this thread.

What look like white/red wires are actually yellow/red wires which are for the neutral safety switch which goes to the ignition switch and into the boat harness back to the engines. See Diagram. As also mentioned they only prevent the starter from cranking if the stick in not in neutral and will not effect the engine once running.

View attachment y4mX_Gizg-gyyLBf_RvIAqYWozmvthUx6JjbqM--jvTRse1OjRu_fWHCMdDLcR4YXLtW1MBP3WwsVlVZH_Y1z1C6BLcHLEJFgjLi
If you do not have one you should find a copy of the MerCruiser manual I think # 16 should cover your engine. There is a wealth of info inside including wiring diagrams for your engines. FYI the only other wires that are associated with the controls are for the switch in the handle that controls trim. Here is that diagram I can only assume the Dual stick control wiring is similar as there are 2 of everything.

View attachment y4mI5GKl2lEF1pMzv6qRvMTTuIGqMLHGjTOiFCMEVxjTS0KLVFRLzBCK_TfwX0uruoF0opKxKlDoUfcXav76CkdCy0zqzgTwV30q

One thing nobody has mentioned that moves with RPMs is the Tach, I have read on this forum where a bad tach could short out the ignition. I know its a long shot but if the tach shorts out at a specific point in the needle sweep it could cause an intermittent issue like this. You could try swapping tachs between engine and see if the problem moves.

My sea ray has the single lever version of yours and I agree that it is not great and kinda sloppy but it is 27 years old and it works for now. Beside it looks like a giant PITA to replace.

Good luck and keep us posted. Back to the real world tomorrow then batten down the hatches for some crappy weather Tuesday as TS Jose goes by us on its way to visit you.

Mike

 

[Lou C]

A puzzling problem for sure, since none of the wiring that is in the area of the throttle control should affect the ignition system when the engine is running...
​The only thing remotely like this that I experienced with my boat was this:
​Once in a while, when trimming the boat, the engine would stumble briefly. What it turned out to be was bad battery wiring, because the trim system draws so much current that it was dropping the system voltage to the point that the ignition cut out for a split second. In addition to this, when trimming and holding the steel steering wheel, I would get a slight tingle once in a while. Both problems were solved by repairing old wiring. I am wondering, when you touch the throttle, is it possible that the trim is getting activated? I'm sure you'd feel/hear it, but in that pic, it looks like the trim wiring is right next to either the shift or throttle cable....

 

[tpenfield]

Thanks for the replies. :thumb:

Yes, it looks like the wiring is the Yellow/Red (not white/Red) for the neutral safety feature for the starter. I do have manual #16 and verified the Yellow/Red.

Theories now would be:

Kill switch wiring
Tachometer
Trim

FWIW - both trim buttons are on the Port throttle lever. I do trim the outdrives while running and do not see it stumble the engines at all.

I ran the boat yesterday, but at only about 3K RPM and did not notice any problems. I'll have to see if the problem still exists in the 3500 RPM range. Could be the tachometer. Time will tell. Got to wait for the hurricane Jose weather to pass to get some calm seas again.

My boat is coming out for the season in a couple of weeks, so I'll be able to go through the wiring then.

 

[biggjimm]

I was going to mention the tach as well.
My old merc 140 would stumble at a certain rpm (don't remember now) & it ended up being the tach. It wasn't accurate anyhow so I replaced it with an auto meter unit & all is well.

As far as controls go, I'm not real familiar with the fancy stuff but I did see a couple sets of livorski (i think that's the spelling) on eBay the offer day. One was a new old stock unit that was very reasonable.

Good luck. I hate chasing those intermittent ghost problems. But, as Is usually the case for me, it'll be something simple when you finally find it.
Jim

 

[tpenfield]

Quick Update:

I have the boat out of the water for the season now, so I thought that I would check out the tachometer, to see if that is briefly shorting out the ignition. I have Googled "tachometer testing" but much of the results is geared towards testing the accuracy rather than an input short.

I'm not sure what the circuitry for the tachometer is like, but I assume there is some sort of capacitive input and the tach 'reads' the ignition system pulses coming from the coil on the engine.

I am thinking that if the problem is related to the tach, then adjusting the throttle is essentially changing the RPM and maybe that change in RPM is causing a very brief short circuit on the input.

I just want to see if there is a way to test the circuitry for an intermittent short :noidea:

I do have an oscilloscope and could rig up an oscillator to provide an input, simulating the ignition coil.

Any tachometer experts in the crowd ? :hail: