Shift interrupter issue

[FliesAndFloats]

I have an issue with my engine (5.0MPI w/ Alpha One gen 2) quitting when going into and coming out of gear. I can see the shift interrupter engaging when I put the throttle into gear. I've been chasing the engine quitting issue since I bought the boat two years ago. I had the outdrive resealed a few months ago and requested that the mechanic inspect the lower shift cable. He said it seemed relatively new and moved freely. However, today after discovering the shift interrupter lever moving when putting the drive into gear, I removed the lower shift cable and moved the sleeve at the end of it by hand and found it very stiff to move. I assume that it should move very freely and this stiffness is what's causing the shift interrupter to engage. It looked like somebody used some sort of grease on the end of it that gummed it up. Does this sound like something I should try and clean up with solvent and WD40 or something or does it sound like my lower shift cable may, in fact, need to be replaced?

 

[Bt Doctur]

a sticking/stiff lower shift cable will operate the shift interupter going into gear. May be from incorrect routing, heat damage from the exaust pipe or physical damage(bent/stepped on. incorrectly installed)

"it should move very freely and this stiffness is what's causing the shift interrupter to engage"
Basically, put grease on your fingers and you should be able to move it in and out with just 2 fingers

 

[Rick Stephens]

With those symptoms it almost puts it into automatic 'replace the lower cable' zone. While other possibilities exist, 99% of the time you can buy a cable and replace the original and know you'll get the problem fixed.

 

[FliesAndFloats]

Here's a video of it going in and out of gear. I am considering just designing a new interrupter system and fitting it to the existing cable. The design that Mercruiser uses here is in desperate need of a retrofit.

 

[Bt Doctur]

The factory design works correctly,
If it is doing that with the motor NOT RUNNING , it may be normal because the clutch dog isnt lined up to fully go into gear.
If its doing that with the motor running, you need a new cable or drive service.

 

[achris]

You can see as it's coming back out of gear that it 'overshoots'. The only thing that can cause that is a sticky/binding cable. I'm with BtD, the factory system works very well when it's all working properly. Don't go trying to 're-design' it. After all these years, if there was a better way of doing it, Merc would have done it.

Chris.........

 

[Scott Danforth]

its a $30 cable, replace it and go boating

 

[FliesAndFloats]

Thanks for everyone's advice on this. I keep the boat on a lift in the backyard. Any work on the stern drive requires the logistics of taking the boat to get hauled out, arranging transportation to the boat, et cetera.

Before I continue, I want to say that what I'm about to say is meant with the utmost appreciation for all of the feedback from everyone here, but I'm about to be critical of Mercruiser on the design.

I can't disagree more with the "it works fine" attitude regarding this system. An otherwise working cable drive system that must be replaced at increased intervals due to a method of failure where the engine quits when maneuvering in close quarters should be the poster child of a bad design. We all know Mercruiser's old style manifolds had a method of failure that resulted in many, many dead engines for decades before they revised the design of those manifolds.

 

[Baylinerchuck]

Umm, why would the cable need to be replaced at increased intervals? What caused the cable to fail? If the cable wasn't binding or misadjusted, the shift interrupt contact wouldn't be making when going into gear. It's only designed to make when going out of gear when the shift dogs have pressure from the prop being in water. I'm not seeing the necessity to redesign a device that works as intended when adjusted properly with working cables. This system is proven and in use in thousands and thousands of mercruisers across the globe. One mans opinion.

 

[Bt Doctur]

2 things come to mind. The cable was intentionally mis-routed because the mechanic was lazy or didnt know the correct route or it was just easier to route it wrong. Second reason is that the motor was overheated or run a bit hotter than normal and being extremely close to the Y pipe or touching it caused it to melt.
Remove the cable from the shift plate, put grease on your thumb and index finger, move black plastic sleeve fully in and out.If you cannot do this the cable is damaged or the mechanism at the transom is dry and corroded or there is lower unit drive damage.
Your going to have to pull the boat and pull the drive to inspect the compoments it`s the only way.
see page 97 http://www.boatfix.com/merc/Install/gas/86017211.pdf

 

[achris]

.....I can't disagree more with the "it works fine" attitude regarding this system. An otherwise working cable drive system that must be replaced at increased intervals due to a method of failure where the engine quits when maneuvering in close quarters should be the poster child of a bad design. We all know Mercruiser's old style manifolds had a method of failure that resulted in many, many dead engines for decades before they revised the design of those manifolds.

:facepalm:

The system as designed works perfectly well. I have a 2006 engine in my boat, still on original cable. My previous engine is in a friends' boat, 1994, still the original cable. Another friend of mine, 1995 engine, still original cable. Yet another friend has just bought a boat with a 2005 engine, still the orginal cable. Beginning to see a theme here? The theme is "Look after the machine and the machine will look after you". The only reason those cables need replacing is if something else has caused them to fail, usually water ingress. Do the maintenance and that won't happen. When the bellows (or anything else for that matter) look like they need replacing, replace them. Don't wait until they fail and take hundreds of dollars worth of other gear with them. Someone here has a post signature that reads something like "When will people learn that impellers are not 'wait until it pukes' items"..... Nothing truer, and it actually applies to EVERYTHING on a boat.

'Redesigning' that system to do away with the switch is fraught with hazards. If you get it wrong, say 'good-night' to your drive.... Just to put it in perspective, I'm an engineer, and the only systems I can think of that do away with the switch are far too complex to be as reliable.

Chris.......

 

[thumpar]

The shift interrupt system has a long history of working well and it a super simple design for the complexity of the operation. If you don't like it you can rip it all out and get a Bravo. Not a cheap solution to a $30 overdue shift cable problem and you will still have cables that wear out and can be abused.

 

[Bondo]

but I'm about to be critical of Mercruiser on the design.

I can't disagree more with the "it works fine" attitude regarding this system. An otherwise working cable drive system that must be replaced at increased intervals due to a method of failure where the engine quits when maneuvering in close quarters should be the poster child of a bad design.

Ayuh,.... Ya might think so, but ya couldn't be any more Wrong,....
While the system looks simple, the operations are quite complex,...

The Merc system works perfectly with abit of standard Maintenance,...
Replacement of the lower shift cable might come as soon as 5 years, or as late as 10 years, dependin' on the maintenance provided,...