DonS, shift interrupt switch question...

[aggiedave98]

DonS,<br /><br />A month ago, I posted about getting stuck on the lake. I think you were right as I just got the boat out of the garage and started messing with it again for the 1st time since I replaced the distributor cap, etc. <br /><br />It does look like the shift interrupt switch is the problem!! Should I just order a new one, or is there anything else I can do in the mean time? Even if I get a new one, what else do I need to check? <br /><br />Can somebody explain exactly how that is supposed to work? By that I mean when you shift, should it go one direction and immediately pop itself back to the "neutral position?"<br /><br />Thanks for all the help! This is a great board!!<br /> in the man<br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=24;t=010570#000007 <br /><br />After re-reading you post, you may just have a shift cable that is getting stiff and causing the problem. It will only get worse and kill the engine every time you shift.<br />You have a shift interrupt switch on the engine that kills the ignition for a split second to relieve the pressure on the shift dogs (they are reverse cut to hold them in gear) so the drive will come out of gear without a lot of physical force that would damage the gears. The shift interrupt system with a stiff shift cable will hold the switch activated and kill the engine.<br />It's a very common problem and a new cable will usually cure the problem. But checking everything is necessary before you just change the cable because a post you read, there are other things that can cause the same thing in the shift interrupt system.<br />Here is another site you might find interesting, plus, you really need to get the OEM Service manuals for your engine and drive. Without them, you are severly handicapped in your maintenance.

 

[Bondo]

Re: DonS, shift interrupt switch question...

Originally posted by aggiedave98:<br /> if I wanted to take the boat out today, would it be ok to disconnect it for 1 trip, or is that dumb??

The Cable that's creating your Interrupt Switch Problem is the Lower Shift Cable,..... The 1 going down to the Outdrive..........<br /><br />If your Controller Cables are Also Junk,..........<br />By All Means,... Replace them All..............<br /><br /><br />Ayuh,.......... Really Dumb Idea........... It Could escalate to Catastrophic Failure............<br /><br />But,.... Hey, It's Your Boat..........

 

[aggiedave98]

Re: DonS, shift interrupt switch question...

Just messed around a little more w/ it and here's some more info:<br /><br />I now understand I think what's supposed to happen (after reading the manual and looking at how it works). Correct me if I'm saying this wrong:<br /><br />It's only supposed to only push that switch (to ground it) during a shift BACK to neutral. <br /><br />What's really happening is this (with the boat off):<br /><br />If I got into forward quickly, the switch will engage and even stay engaged a few seconds. If I shift into forward slowly, it's ok.<br /><br />If I shift into reverse, the switch engages and STAYS engaged all the way through reverse!! If I go into reverse and then puth the throttle forward a little (but still in reverse) the switch disengages.<br /><br />So, obviously this is the cause of all my problems. How do I fix it?? Will just replacing the cables be enough?? Is there anything I need to clean or lube?<br /><br />Thanks!

 

[Don S]

Re: DonS, shift interrupt switch question...

Yep, replace the cable. It's getting either stiff or worn inside and binding a little. Doesn't take enough resistance that you can feel it, but the shift interrupt system will.

 

[aggiedave98]

Re: DonS, shift interrupt switch question...

ok, should I replace all 3 cables (the 2 cables for the interrupt plus the throttle?)<br /><br />BTW, more info... I took off the cable on the port side and that's the one that is my problem. And I have had a stiff shifter for a while so this should solve lots of problems!!

 

[aggiedave98]

Re: DonS, shift interrupt switch question...

if I wanted to take the boat out today, would it be ok to disconnect it for 1 trip, or is that dumb??

 

[Don S]

Re: DonS, shift interrupt switch question...

The only cable that can cause your problem is the shift cable from the engine to the outdrive. You might want to pull the drive and check the cable and the shift shaft in the bellhousing. If it was real stiff, it could cause the same problem. Just disconnect the cable from the engine and move it, it should be VERY Smooth, if not, it's bad and needs replaced.<br />If you try to shift out of gear without the shift interrupt system, you can damage other things, including the shift dogs in the drive. <br />How much are you willing to pay for running without the shift interrupt sytem working?

 

[aggiedave98]

Re: DonS, shift interrupt switch question...

DonS, Bondo, thanks for the info... I was asking you guys about running w/o it because I had NO idea, not because I wanted to do something dumb.<br /><br /><br />Can you guys explain which cables go where? Are there two cables that go from the remote? 1 goes to the top of the engine for the interrupt and the other goes to the throttle?<br /><br />Then the 3rd cable goes from the top of the engine to the outdrive?<br /><br />Let me know if that's right.<br /><br />Now where exactly does it go into the outdrive? Keep in mind I've never taken my outdrive apart. I'm pretty mechanically inclined, but until I do something, I generally don't know much about it. (I rebuilt my suburban's auto tranny a couple of years ago w/o knowing anything about it beforehand). So I know I can do it, but just need a little instruction.<br /><br />DonS, what do you mean by "pull the drive"<br /><br />That cable is definitely stiff and needs to be replaced... I'm sure of that! How does that cable get moved? What on the outdrive is moving it??<br /><br />Thanks guys!!

 

[Bondo]

Re: DonS, shift interrupt switch question...

I'm pretty mechanically inclined, but until I do something, I generally don't know much about it. (I rebuilt my suburban's auto tranny a couple of years ago w/o knowing anything about it beforehand). So I know I can do it, but just need a little instruction.

You Need a Shop Manual,........... Don will be back,+ Probably post a link to Where to Get 1..............<br />I find it hard to believe you rebuilt a tranny Without some sort of Manual.......<br />

Can you guys explain which cables go where? Are there two cables that go from the remote? 1 goes to the top of the engine for the interrupt and the other goes to the throttle?<br /><br />Then the 3rd cable goes from the top of the engine to the outdrive?<br /><br />Let me know if that's right.

Ayuh,.........<br />You've got that much Right.........<br />

DonS, what do you mean by "pull the drive"<br />

Your Questions are Many,.... And, Your Knowlegde is Short............<br />I Believe I can speak for Most of Us here at iboats,.......<br />We All Love to Help,...... But,... Until You get a Manual,+ can Speak the Lingo..........<br />There's Not Alot We Can Do...........<br /><br />AnyWay,............<br /> You can get Started Here.................................................

 

[Don S]

Re: DonS, shift interrupt switch question...

When I say "Pull the drive" that means remove it from the boat.<br />Here are a couple of links you need to look at.<br /><br /> Mercruiser Service Manual <br /><br /> Merc info

 

[aggiedave98]

Re: DonS, shift interrupt switch question...

Bondo,<br /><br />Of course I didn't rebuild a tranny w/o a manual... I had 2 manuals and the best part... a step by step video!! Put a 13" TV and VCR in the garage... put the remote in a zip-lock and hit play... rewind.. play. 2 weekends later, it was up and running!<br /><br />I'll go ahead and get the mercruiser manual. I have the Haynes one, but was told here to get the factory manual last month.. still haven't done it yet.<br /><br /><br />But Don, do you mean the lower part, like I would to replace the impleller, or the whole thing??<br /><br />Thanks guys, I appreciate it.

 

[Don S]

Re: DonS, shift interrupt switch question...

Complete outdrive, that is the only way to get to the shift cable.<br /><br /> http://www.mercstuff.com/alpharemoval.htm

 

[aggiedave98]

Re: DonS, shift interrupt switch question...

wow. venturing into new territory... how long would you say that takes to do?

 

[tommays]

Re: DonS, shift interrupt switch question...

it depends on what doesent come apart because of corrision<br /><br />if its you first time it will take a while<br /><br />it took me a while because i find it better to go real SLOW the first time i do something <br /><br />if you rush you will miss something and be takeing it apart again<br /><br />tommays

 

[Don S]

Re: DonS, shift interrupt switch question...

It doesn't matter, it will take as long as it takes you to do the job.<br />You try to do it within a certain time frame and you will screw something up for sure.

 

[aggiedave98]

Re: DonS, shift interrupt switch question...

ok, that doesn't look too bad. I'll get the manual and go from there.<br /><br />Do I need to buy an alignment tool that is shown at: http://www.mercstuff.com/alpharemoval.htm ?<br /><br />Are there any other special tools I need?

 

[Don S]

Re: DonS, shift interrupt switch question...

Yes you NEED an alignment bar. And you need to check the alignment at least yearly. You can buy a lot of alignment bars for the price of one engine coupler that you have to remove the engine to change.<br /><br />You have the guys at WM looking for the wrong type cable. Go to a Mercruiser dealer or online and get a real Mercruiser shift cable for an Alpha drive between the engine and drive. The ends don't change.<br /><br />Not trying to be mean, but if you don't start reading (and UNDERSTANDING) a bunch of the information you have been given, you are going to have some real problems.<br />Changing the shift cable and getting it adjusted right is not a walk in the park. And if you aren't mechanically inclined and don't follow the instructins completely, you are in for big problems.

 

[aggiedave98]

Re: DonS, shift interrupt switch question...

I called West Marine asking how much the cable is and the guy told me I had to bring in the cable to find out which "connector" it had on each end and how long a cable I need.<br /><br />Shouldn't I be able to find out what I need before taking it apart so I can do it all at once?

 

[aggiedave98]

Re: DonS, shift interrupt switch question...

Don,<br /><br />Sorry for asking all the questions before really investigating enough myself... yes I realize the trouble I can get into... but I have a 16 year old boat. I also have a 15 year old suburban. I'm 29 and I bought them both from my best friend's dad. I grew up w/ them. They are the way I learn about cars/boats. When things break, I figure out how to fix them.<br /><br />I know I can get myself into trouble if I don't do it right, but if I don't try it, I'll never learn!! I appreciate the help and appologize if I'm asking too many questions before digging into it myself. <br /><br />Like w/ the tranny I rebuilt, I can read and read but until I actually get in there, I don't fully absorb what's really going on. That's just how I personally learn best.

 

[Don S]

Re: DonS, shift interrupt switch question...

I don't mind a lot of questions, and it's great that you want to learn, but you have to get into it first, and just asking questions and trying to order cables from WM without first pulling the drive and checking the old cable is what I am talking about. You need to find the problem first......then order what's bad. <br />Had you pulled the drive and checked the cable, you would have know what kind of cable and ends were on it and that the sales person was talking about the wrong cable.