Need help with adjusting shift cable on Mercruiser Alpha 1 drive..

[Ps91Rick]

Hi all.. I’m new here.. You guys seem like you’ve got a wealth of knowledge and I thought I’d ask a few questions before I start digging into my shift issue further.

Backstory.. I’ve got an ‘87 Cobalt DV18 with Mercruiser (230/v8) and Alpha 1 (not sure gen # off the top of my head). I decided months ago to change out the original throttle/shift controller (Quicksilver Commander xxxx — don’t recall the #) to the latest Mercruiser 4000 Gen II with brand-new cables that are compatible with it. The old stuff was completely stock from late ‘86 as it had date codes.. lol. The old controller button for throttle-only wasn’t working and I just decided to put a new one in.

So.. I’ve done that and I fired her up the other day.. She started way easier than expected considering she’s been sitting for a year. I can get her to go into forward with the usual clunk and then hit the throttle a bit and the prop starts spinning as expected. But, if I put her back into Neutral and slip her into reverse, she goes with the usual clunk but if I throttle up any amount, the engine dies — every time. The guys on the Cobalt forum think its just a matter of adjusting the shift cable.. But I ran across a very old thread here talking about an Alpha 1 Gen II shift cutout switch.. which shouldn’t have any effect when not in water.

For now I’m gonna just sit on it until I have a clear path forward.. If anyone has any suggestions, please do tell!!

 

[alldodge]

I'm with you and would think about the shift interrupter switch. Need to watch the shift switch when moving in reverse to see if it moves any. If it does, that's what's doing it, and then it may need more grease on the control

 

[tpenfield]

:welcome: to iBoats . . .

It does sound like the shift interrupter, so maybe go through the control and linkage to see if you can track it down.

 

[Ps91Rick]

Ok.. just a followup.. for whatever reason I apparently didn’t know anyone responded to my post.. Oh well.. gotta check the forum settings on my profile.

Anyway, I’d like to solve this.. So.. Where can I find this shift interruptor on this boat .. Is it in the engine compartment? I’m assuming so as it sounds electrical in nature. I saw the HOW-TO thread describing the shift interruptor but the diagram in that thread looks like the switch is in the control... ??? The only switch I saw was the neutral safety switch or whatever its called... thoughts??

 

[alldodge]

Iboats stopped sending out emails a long time ago. Need to check your self daily

If you login it should show how many messages you have from threads so long as you have notifications set to tell you is you respond to them or reply

The shift switch is on the shift plate where the shaft cables come together

This is how to adjust and what to look for

 

[Ps91Rick]

I had the entire controller taken apart — guts and all.. I did that during the install because I had assembled everything but found I needed to untangle the cables inside the hull area and when I went to remove the cable hold-down screws the head of one of them snapped off.. Doh! So I eventually had my brother with the tools drill it out and re-tap it to accept a new screw.. but needed to remove the metal shavings... in doing so I took it apart completely and wasn’t sure how the gear with the teeth went.. I’m now wondering if perhaps I’ve got it off a cog or something. Below is the guts of it showing the switch I believe you’re referring to.. Is that a correct assumption? I’ll admit that I loath removing the controller.. ugg!

 

[Baylinerchuck]

No, the shift interruptor is on the shift plate on the engine. The switch shown in your picture looks like the neutral safety switch in the control.

The shift interruptor is designed to stall the engine for a split second so the outdrive slips to neutral from either forward or reverse. Any binding of the cable will cause the switch to close, killing the engine. It’s actually a simple, clever design IMO.

 

[alldodge]

Agree, that's the neutral safety switch

Switch is behind shift cables

 

[nola mike]

And to clarify, if you have a problem with then safety switch in the controller, the engine won't crank. if it's a problem with the shift interrupt switch, the engine will crank but you will get no spark.

 

[Ps91Rick]

Excellent! Thanks guys! I will take a gander at the shift interruptor switch next.. that is what I was hoping — that it was basically a cable adjustment issue (I believe).. I promise that I’ll report back here with my findings.. I’m assuming that I can probably diagnose this without running the engine initially anyway..

 

[Ps91Rick]

Ok. I’m back on this again now that my garage is cooler. I took a video of the offending area while I operated the shifter and sure enough I see the shift interruptor switch being toggled.. So, with that in mind is it mostly just a matter of playing with the adjustment screws on the new shift cable and finding the sweet spot? Is there a best way to accomplish this task before I just try something ad-hoc and “wag” it..

 

[alldodge]

Start with the link below and read thru to see how to adjust the shift cable

http://boatinfo.no/lib/mercruiser/manuals/mercruiser6.html#/32

 

[Ps91Rick]

Thanks!!

Hmm.. I might have to wait as my laptop needs some TLC at the moment and I don’t have Adobe Flash on my iPad which it says is required to look at that material.. Doh!! Hopefully I can look later once my laptop is working again

 

[alldodge]

May help

 

[Ps91Rick]

Sweet! Thanks so much!! I really appreciate that!

 

[Ps91Rick]

<empty - delete>

 

[Ps91Rick]

Ok.. I’ve followed the instructions (yes, I was able to download the entire stern drive manual once my computer was up again).. so I re-adjusted the lower shift cable and in the process found the cotter pin holding the rear brass barrel was never bent to spread the legs.. good find there. I guess even the guys who do this daily forget things from time to time. Glad I found it before it decided to dislodge..

Anyway, the lower shift cable is at 6” and then backed off 4 turns as instructed. I installed it and now followed the steps to reinstall the upper shift cable that runs to the control. I’m now stuck at steps 11/12. I’ve got the control set to WOT in reverse without issue.. but the prop when turned clockwise will not fully lock. They discuss this problem in step 16a on page 2A-23. So I moved the adjustable stud up a bit several times until the prop would lock when turned clockwise. When I get the adjustable stud near the top (maybe at about 80-85% of travel) it will lock ok. But then the shift cutout is in the wrong place — its not in the detent at all and is actually on the top nub.. is it possible to adjust the shift cutout or ??

Any thoughts on proceeding here?? I’m lost on what to do next.

 

[nola mike]

The 4 turns is for the remote shift cable, not the lower cable (that's a straight 6"). Doesn't sound like it's set up correctly.

 

[Ps91Rick]

Hmm.. I guess I misread the instructions — Drive unit shift cable is not the same as the remote control shift cable. I don’t know how I managed to mess that up.. At least it didn’t hurt anything! Thanks much!!

 

[Ps91Rick]

Ok.. a quick follow-up.. I went back and redid the entire procedure - for the lower and upper cables and got things all figured out. I’m pretty much at the end of the travel for the adjustment stud but the clutch is fully engaged in both directions. I briefly fired it up outside and checked both forward and reverse and they’re working fine..

One note for potential people reading this in the future.. When you’re trying to lock the prop in either clockwise or counterclockwise directions — PLEASE lower the drive unit fully!! That was one thing I messed up on.. I had it fully up and it wouldn’t quite engage the clutch until I lowered it.. I recalled reading that somewhere in one of the other threads here.. Thanks all for your amazing help!!!!