Alpha 1 shift problems

[Si Rey]

I have an Apha 1 gen 1 stern drive coupled to a Merc 5.7. The outdrive shifts into forward and reverse gears fine, but binds when trying to take it out of gear. It binds when taking out of forward and reverse. I tried adjusting the shift cables as per Merc manual without any success. I have disconnected the throttle/shift lever to isolate the problem and it appears to be in the stern drive unit. The shift cable doesn't bind, it feels like there is something grabbing in the stern drive. If I turn the engine off and restart it will start in neutral and everything is fine until I try to shift out of gear again. When the engine is off it shifts fine into and oout of gear it inly happens when the engine is running. I recently purchased this boat with this problem and thought it was just a matter of " A little adjustment". This is not a problem that just suddenly showed up. I suspect it has been there awhile. Thank you in advance for any help that can be provided.

 

[Don S]

Re: Alpha 1 shift problems

Sounds like the shift interrupt switch isn't working. It has to work in order to release the load on the reverse cut dog type clutch in the lower unit.
With the engine running and in neutral, activate the shift interrupt switch and see if the engine dies....... It should.

 

[Si Rey]

Re: Alpha 1 shift problems

And what should I do if it doesn't die? Would the same be true for the shift interrupt switch shifting from forward?

 

[Don S]

Re: Alpha 1 shift problems

And what should I do if it doesn't die?

Then it's time to troubleshoot the shift interrupt electrical wiring and switch.
Click here and scroll down to page 1C-36, there is a section on troubleshooting the shift system.

Section 2 of the OEM Service Manual covers adjustments.

 

[Si Rey]

Re: Alpha 1 shift problems

Thank you for the 411. It looks like my answer lies within. There is a lot of very good info in that link. I'll post my discoveries in hopes it will help others. I do have the clymer manual but it doesn't give any information for trouble shooting.
Thanks again

 

[Don S]

Re: Alpha 1 shift problems

I do have the clymer manual but it doesn't give any information for trouble shooting.

 

[Si Rey]

Re: Alpha 1 shift problems

The cut out switch was cutting out too late and adjusted accordingly. When shifting from reverse to neutral and from neutral to forward the roller on switch remains centered as before-no adjusments were needed. I understand that the roller is suppose to remain centered so the engine stays running. I don't understand the purpose of the cut out switch in relation to my problem. I also checked control cable end play and it was normal.

 

[Don S]

Re: Alpha 1 shift problems

The reason for the shift interrup switch is to stop the engine for a split second so the reverse cut gears in the clutch dogs will release. This is only a problem when in the water with a load on the prop. Will not be used on land on muffs.
Follow the directions in the manual. Even some Merc techs really don't understand how to adjust them properly, but do eventually find a way to "Make it Work".

 

[sarantis]

Re: Alpha 1 shift problems

Keep focused where Don S says.I have the same problem and in the general maintenance i had checked everything else apart from adjusting that switch.
(i opened the lower unit,changed the sealers,bushings and the cable and the problem still exists)

 

[Si Rey]

Re: Alpha 1 shift problems

It's exactly like you say Don that it only happens in the water under a load. I agree with the idea that it momentarly releases the load on the gears allowing it to shift out of gear. Do you know how the cut out switch gets activated from moving out of gears if the roller is suppose to stay centered in the seat?

 

[Don S]

Re: Alpha 1 shift problems

It's only supposed to stay centerd in the seat when you are doing anything but shifting out of gear. When you shift out of gear the roller moves off center and activates the shift interrupt switch.
It happens quickly, but what happens is this. When you start moving the shift lever from Fwd. or Rev. back to neutral, the helm to engine shift cable starts moving. The cable from the engine to the drive (aka lower shift cable) will not move. This causes that Y bracket the Shift Interrupt Switch sits in to move which in turn activates the Shift Interrupt Switch. This in turn stops spark to the engine and releases the load on the lower shift cable. Once the load is off the cable, the drive comes out of gear because you are moving the lever. As the pressure is off lower shift cable, the Y bracket recenters and allows power back to the ignition.
And it all happens in a split second when it all works properly.

 

[Fishermark]

Re: Alpha 1 shift problems

Someone has posted a more detailed and technically correct article on the subject that this... but basically, the switch mechanism is designed to detect and activate when the pressure or tension between the two cables attached to it is different one from the other. In other words, as you are shifting and the cable meets resistance as it is trying to come out of gear, the switch is engaged, which causes the engine to "stumble" which allows the outdrive to come out of gear which releases the pressure on the cable which allows the switch to go back to center which allows the engine to continue running.

Simple!

 

[Fishermark]

Re: Alpha 1 shift problems

Looks like Don and I were posting at the same time!

 

[Si Rey]

Re: Alpha 1 shift problems

That makes perfect sense! When I checked the roller gap to the y bracket it was much greater than specs allow. Which would not allow the engine to stumble and release load on lower end. I re-adjusted according to specs (Info provided by Don) and roller engages much sooner now than previously. The real test will be in the water. Should the engine cut out prematurely I also know that I have adjusted it too much and how to fix that! Hope this works!
Thanks again!!!!!!!!!!!!!
Michael

 

[ugbandtulsa]

Re: Alpha 1 shift problems

Si rey,

Think of it like this;

Take a 5 speed car, get up to speed in 2nd gear. Then, while maintaining throttle, try to pull the car out of gear. Wont work, will it.? Now, if you release pressure on the throttle and pull on the shifter at the same time, the stick will fall right out of gear. That's the reason you need the interrupt to work. Easy fix.

 

[pete44]

Re: Alpha 1 shift problems

Hello all ...have the same issues...it was no fun trying to manuver a 1 ton boat when my reverse kept killing my engine....a buddy and I finally got boat pointed to use forward gear only....only to find out next I was running REALLY hot....around 250...only went about 100 yards and had to turn boat back around and oar it in....I am checking on a thermostat today,,(hopefully that is it)..when I ran boat with the "fake a lake" I saw water running out of weep hole on drive so I am hoping that pump/impeller is OK..It is an Alpha-1 drive on a 87 sea ray with a 3.0 liter/181cu in/130 motor....its funny how people will stare and not offer to help these days..Appreciate the info Don,you have helped me before ....Take Care,Pete

 

[Don S]

Re: Alpha 1 shift problems

Kind of hard to tell by your post Pete, but if you are asking for help, it's best to start a new thread. Or yours will be lost at the end of someone elses thread. Besides, it's very confusing to try and figure out which replies go to.