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Alpha 1 and Dying in Reverse

Nordie

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Recently purchased a boat and the reverse isn't happy. I went through and adjusted the lower cable to spec. Anytime I put it in reverse (in the driveway not running) as I travel it throws the interrupt into kill the engine. I can't even get to throttle in reverse. On the water it's the same result, I can click it into reverse at idle and maneuver around, but if I go to throttle up the (I'm gonna call it a switch) breaks the ignition circuit. What am I missing?


The problem seems simple and something seems out of adjustment.

Obviously forward is completely fine, just reverse, what do you guys think I should do? Do I need a new cable, or is it really something simple?
 

Outdrive1

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Alphas have a shifter interrupt. It kills the ignition momentarily when you shift to let the dog clutch engage. You probably need an adjustment to let it interrupt and go back to normal when you’re shifting in reverse.
 

Fun Times

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Recently purchased a boat and the reverse isn't happy. I went through and adjusted the lower cable to spec. Anytime I put it in reverse (in the driveway not running) as I travel it throws the interrupt into kill the engine. I can't even get to throttle in reverse. On the water it's the same result, I can click it into reverse at idle and maneuver around, but if I go to throttle up the (I'm gonna call it a switch) breaks the ignition circuit. What am I missing?


The problem seems simple and something seems out of adjustment.

Obviously forward is completely fine, just reverse, what do you guys think I should do? Do I need a new cable, or is it really something simple?
What year is the boat or more importantly the Alpha stern drive? Drive serial number available?

Any known recent service work done to the drive and or shift cable that you know of possibly?

Possibly an aging, stretched out lower shift cable issue as long everything around the Mercruiser intermediate shift shaft of the bell housing is in normal working condition.
 

Nordie

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What year is the boat or more importantly the Alpha stern drive? Drive serial number available?

Any known recent service work done to the drive and or shift cable that you know of possibly?

Possibly an aging, stretched out lower shift cable issue as long everything around the Mercruiser intermediate shift shaft of the bell housing is in normal working condition.

Boat is an 87, I'll pull the numbers this afternoon or tomorrow. I just purchased the boat and allegedly it was serviced every year by a reputable shop in so-cal. Boat is in Nevada now.

I plan on shooting some videos tomorrow, and it seems your consensus is what a lot of people say. If that's the case how difficult is it to replace that shift cable?
 

Fun Times

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Boat is an 87, I'll pull the numbers this afternoon or tomorrow. I just purchased the boat and allegedly it was serviced every year by a reputable shop in so-cal. Boat is in Nevada now.

I plan on shooting some videos tomorrow, and it seems your consensus is what a lot of people say. If that's the case how difficult is it to replace that shift cable?
It can be a time-consuming near day long project for the first time and not being in big hurry to accomplish the task...There are many videos online that may help out here too.

You'll need a few special tools to help such as an OEM 91-12037 Shift Cable Installer & Removal Socket Tool Fits for Mercruiser Alpha One Gen I, II, R & MR... I've read the aftermarket sockets from say Amazon, etc. don't fit, wrong size completely, cause damage, etc... Not worth the savings of a few dollars.

Also need safety Wire Twisting Pliers like this, https://www.harborfreight.com/6-in-safety-wire-twisting-pliers-57397.html

At minimum, an Alignment bar and being aftermarket will work good enough in this case and if you search Ebay under Mercruiser Alignment bar or bar kits, it's more affordable vs OEM and under kits, you can pick a set of tools that you may need either when doing the job now or later on down the water. < That will depend on the price point you don't mind spending on the boats investments if you're going to be doing the work yourself on the transom side of ownership...Might want to opt for a gimbal bearing puller kit set too just in case in which cost investment was mentioned.


The following linked shift cable installation guide that you'll want to read as it's pretty helpful is more so set up for the Alpha Gen 2 drive but the procedure is near the same for the Gen 1 stern drive that you have being an 1987 with a possible slight difference in cable length that may or may not need additional attention depending on the installation directions of the kit bought.... They sell a shift cable kit for your gen 1 as well...,

Grease gun along with mercruiser extreme grease needed, https://www.mercruiserparts.com/mercury-mercruiser-8m0190472-greasex-14oz

Drive install to bellhousing gasket set for the gen 1,

Merc bellows adhesive, https://www.westmarine.com/quicksilver-86166q1-bellows-adhesive-resistant-to-oil-grease-gasoline-and-water-1.5-oz-tube-16351348.html?&adlclid=81286921102c14131a590f5979a985ec&utm_medium=cpc&utm_source=bing&utm_campaign=[ADL][PLA] Engine Systems&utm_content=pla-4577266913610745:aud-808408722x1178678212216342x458244126x16351348&msclkid=81286921102c14131a590f5979a985ec&utm_term=4577266913610745

Mercruiser stern drive service manual number 6, https://www.ebay.com/sch/i.html?_fr...at=0&_odkw=Mercruiser+Alignment+bar&_osacat=0

You will also most likely need Mercruisers 91-95639 shift cable bell housing straight tap,
1719166092052.png

1719165002017.png



:)
 

Nordie

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It can be a time-consuming near day long project for the first time and not being in big hurry to accomplish the task...There are many videos online that may help out here too.

You'll need a few special tools to help such as an OEM 91-12037 Shift Cable Installer & Removal Socket Tool Fits for Mercruiser Alpha One Gen I, II, R & MR... I've read the aftermarket sockets from say Amazon, etc. don't fit, wrong size completely, cause damage, etc... Not worth the savings of a few dollars.

Also need safety Wire Twisting Pliers like this, https://www.harborfreight.com/6-in-safety-wire-twisting-pliers-57397.html

At minimum, an Alignment bar and being aftermarket will work good enough in this case and if you search Ebay under Mercruiser Alignment bar or bar kits, it's more affordable vs OEM and under kits, you can pick a set of tools that you may need either when doing the job now or later on down the water. < That will depend on the price point you don't mind spending on the boats investments if you're going to be doing the work yourself on the transom side of ownership...Might want to opt for a gimbal bearing puller kit set too just in case in which cost investment was mentioned.


The following linked shift cable installation guide that you'll want to read as it's pretty helpful is more so set up for the Alpha Gen 2 drive but the procedure is near the same for the Gen 1 stern drive that you have being an 1987 with a possible slight difference in cable length that may or may not need additional attention depending on the installation directions of the kit bought.... They sell a shift cable kit for your gen 1 as well...,

Grease gun along with mercruiser extreme grease needed, https://www.mercruiserparts.com/mercury-mercruiser-8m0190472-greasex-14oz

Drive install to bellhousing gasket set for the gen 1,

Merc bellows adhesive, https://www.westmarine.com/quicksilver-86166q1-bellows-adhesive-resistant-to-oil-grease-gasoline-and-water-1.5-oz-tube-16351348.html?&adlclid=81286921102c14131a590f5979a985ec&utm_medium=cpc&utm_source=bing&utm_campaign=[ADL][PLA] Engine Systems&utm_content=pla-4577266913610745:aud-808408722x1178678212216342x458244126x16351348&msclkid=81286921102c14131a590f5979a985ec&utm_term=4577266913610745

Mercruiser stern drive service manual number 6, https://www.ebay.com/sch/i.html?_fr...at=0&_odkw=Mercruiser+Alignment+bar&_osacat=0

You will also most likely need Mercruisers 91-95639 shift cable bell housing straight tap,
View attachment 1391912
View attachment 1391909


:)

Thank you very much for taking the time and supplying the links and photos. I'm somewhat mechanically inclined. I'm generally not nervous to jump into something, but this one has me a little nervous.

Like my buddy told me, not matter how bad you fu*k something up you can always pay someone to fix it.

I was checking the throw on the remote? Cable, and seems like it's supposed to be around 3 inches and I am only measuring around 2. Not sure if that really makes a difference.

I'll still update with the serial #, and a couple.of videos.
 

Fun Times

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I was checking the throw on the remote? Cable, and seems like it's supposed to be around 3 inches and I am only measuring around 2. Not sure if that really makes a difference.
Was it to the higher side of 2 inches?

Had one recently that was a fight being an aftermarket lower cable plus needing a new remote cable as well to make it all work together. Might want to prepare for a new remote cable as well.... There should be a number on the cable installed to copy it as the last numbers ought to be the cable length.


Looks like you were reading the service manual already in knowing that info.

Checking Remote Control Shift Cable Output IMPORTANT:
Remote control must provide a shift cable travel (at the shift plate end) of 2-7/8 in. (73 mm) to 3-1/8 in. (80 mm) with a 15-20 lb. (6.8-9 kg) load applied to the cable end guide. Models With Shift Assist: This measurement can be taken by installing the remote control shift cable and using the shift assist assembly (provided) to place the proper load on the shift cable (drive unit shift cable should not be installed). Models Without Shift Assist: This measurement can be taken by lightly pushing and pulling on the remote guide, to place the proper load, [15-20 lb. (6.8-9Kg)], on the shift cable. 1. Place remote control into gear: Right Hand Rotation Drive Unit - Forward gear wide-open-throttle position. Left Hand Rotation Drive Unit - Reverse gear wide-open-throttle position. Place a mark on threaded tube against edge of cable end guide. 2. Place remote control into the opposite gear. Measure the distance between the edge of the shift cable end guide and the mark line in step 1. Total shift cable output must not be less than 2-7/8 in. (73 mm) or more than 3-1/8 (80 mm). If output is incorrect, remote control and/or shift cable must be replaced.

^ From a Merc service manual Page 1C-42.
 

Nordie

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I made some adjustments, and for a second it seemed like it was going to work. Then went back to bad settings. Here's a quick video of what I'm looking at. Keep in mind nothing is tightened down, just in case of more adjustments.

I slid the shift cable down in the slot and it actually seemed to help.

 

HST4ME

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it needs a new lower shift cable
 

chadzilla

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On all alpha style drives whether it be a Mr or a gen II, the shift interrupt switch is only there to interrupt the ignition circuit when going from in gear to neutral. It should not activate any other time. If it is being activated any other time, it is likely that the cable is bad as many others here have stated. The cable adjustment is critical and must be followed per mercury specs. This adjustment is ONLY for new cables. After installation and proper assembly of the cable components, it is as follows. The drive must be installed, push in on the cable while another person slowly rotates the prop counterclockwise until the prop stops indicating the clutch is engaged into the gear fully, turn the brass barrel nut until a measurement of exactly 6" between the center of barrel nut and center of the hole in the shift cable end is achieved. No more adjustment of the cable itself is needed. Period. The shift cable anchor stud on the bracket must be at the bottom of the slot. Only after these two adjustments have been made can you then adjust the control cable to match the intermediate cable. Remove the control cable and shift the control into fwd wide open throttle. Rotate the prop counterclockwise and shift the drive into fwd by pushing in on the cable itself. Note, the intermediate cable must be installed onto the shift bracket. Adjust the control cable to align up with the bracket. Temporarily install the control cable and operate the control both in fwd wide open and reverse wide open. Check the shift interrupt switch making sure that the roller is centered in the v. You may need to make slight adjustments to the control cable to ensure this. If after all of these adjustments are done correctly with a new cable and the interrupt switch is still being activated then there is a problem with the control box or the drive. NOTE: measure the total travel of the the control cable at the shift bracket with no load on it. It needs to be 3" +- 1/8". Now, I have had a few instances where everything was new and correctly adjusted and the interrupt switch would still kill the engine when pulling out of gear. I found that the interrupt switch spring was worn out and replaced it. Inn 30yrs I've only replaced 3 springs. Hope this helps
 
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