Mercruiser - Stalls in Reverse

[NatedoggAZ]

Hello.. having an issue with my 4.3 Merc with Alpha 1

I have watched all the videos I could find.. and read up on almost everything I could find as well. Not all the videos had provided the whole procedures.. I feel like things were left out. Does the outdrive have to be up or down?
Where does the control arm need to be.. just engaging or full WOT in reverse or in forward gear?

Now resorting to someone who can hopefully let me know what to do..

BEFORE: The engine would just cut out when shifting into reverse.. the roller for the cutoff switch would go into the upward position over the resting valley area.

WHAT I DID: I adjusted the lower shift cable (goes to outdrive) to 6 inches as specified. I adjusted the upper control cable as well to fit (minus 4 turns on the plastic barrel). The prop locks in place in both forward and reverse.

NOW: I now have to to where it does not immediately cut off when in reverse. BUT when I move the control arm down any more other than just engaging in reverse (giving it more gas) it would cutoff... the wheel on the cutoff switch would leave the middle groove. That extra movement is enough to move the roller and engage the switch.

Thanks in advance!

-ND

 

[flashback]

Probably need a new lower cable.

 

[Chris1956]

Corrosion often gets to the part of the shift cable that needs to move to engage reverse, making it stiff. This stiffness caused the shift interrupt switch to kill the ign.

 

[kenny nunez]

As Chris just suggested there most likely a build up of corrosion in the front section of the bell housing stopping the slider from traveling enough to engage reverse. You need to pull the drive and clean out that area and also the pocket in the driveshaft housing where the slider travels for forward. A good time to check the alignment and grease the universal joints. With the drive removed you should be able to move the cable slider back and forth with 2 fingers after it is disconnected from the shift plate.

 

[NatedoggAZ]

I am going to try putting the outdrive down and then go through the procedure again.. maybe that will help..

I did not take out the boat at all this year.. this summer was just way too hot... we had a 30+ day span of temps above 110 here in AZ...urgh

The fact that I am now at least able to get it into reverse without it stalling hopefully is an indication that it may just need slight adjustments.. if not.. will have to look into having that cable(s) replaced.. they are maybe 3-4 years old.. with minimal usage so its hard to imagine they already need replacement.

-ND

 

[Chris1956]

The shift assist switch kills the ignition whenever shifting is hard, to unload the gears and make shifting easier. A binding shift cable simulates loaded gears. It makes no difference if the outdrive is up or down.
Put the flusher on and see if she still stalls. If so, the cable is the culprit.

 

[alldodge]

The shift assist should not even function (no movement) on muffs because there is no load

 

[NatedoggAZ]

Hello.

The engine no longer stalls immediately in reverse after I adjusted the shift cable. It now only stalls when I go towards WOT in reverse. That extra distance on the cable is enough to activate the kill switch.

 

[alldodge]

Hello.

The engine no longer stalls immediately in reverse after I adjusted the shift cable. It now only stalls when I go towards WOT in reverse. That extra distance on the cable is enough to activate the kill switch.

That should not happen

The shift interrupter should "only" activate when in gear (F or R) and under load (in the water) when shifting into neutral

 

[NatedoggAZ]

That is why this is totally weird... Its not under load (on muffs) and running in my driveway. Other than getting a barrel or something.. I'm not sure if I can simulate the prop being under load...

When I slowly shift into forward.. I do not see the wheel move at all.
When I put in full reverse, the wheel goes over the resting groove.
Here it is creeping up:

 

[NatedoggAZ]

Man... I don't know what I did...but its working now... doesn't die in reverse any longer..even on load.

I did put the drive down as far as I could without it hitting the ground and went through the procedures again...

..Maybe that was just it...whatever..it works..

Thanks for all the input!

ND

 

[Grub54891]

Lack of use may cause the cable to get stiff also. Think like if you don't use year car much the brakes can get rusty rotors or such. If you use things a lot they don't have issues with corrosion as much.

 

[alldodge]

I did put the drive down as far as I could without it hitting the ground and went through the procedures again...

Didn't notice you said this prior but the drive has to be down. Trying to do it with the drive up put stresses in areas that would not normally be found while running

 

[Bt Doctur]

 

[NatedoggAZ]

Yep! That was one thing the video left out.. the position of the outdrive has to be down.. mine was all the way up in the trailer position!

I'm guessing it could have been a combination of the lack of use.. and the drive being in the upwards position...

Hopefully this information can help the next person!

Thanks again!

-ND

 

[stresspoint]

you realy shoud not be running the motor with the drive fully up , it will chew out u joints in no time..

 

[Scott Danforth]

Is this the same 1988 boat? if so, buy a new cable. they last about 15 years

 

[NatedoggAZ]

I had the cable(s) replaced either when I had my transom redone in 2018.. or when my engine blew in 2020... so they are not that old.

I only ran the motor and engaged the prop a for maybe 30 seconds in forward and in reverse to ensure the prop engaged.. probably no harm done.

-ND