Mercruiser 140 stalls when I shift into reverse

Al Bell · Oct 26, 2008

I recently purchased a Glastron Carlson with a Mercruiser 140 inboard and Alpha one 165 outdrive. The boat runs great forward, but when I attempt to put it in REVERSE it stalls. I was told that it might be the shift interrupt switch. Does anyone have any advice on what the problem might be?

Don S · Oct 26, 2008

Re: Mercruiser 140 stalls when I shift into reverse

The shift interrupt switch is working fine, that's why it stalls. The problem is most likely a rusted and corroded stiff moving lower shift cable. You can download an OEM service manual here.
http://forums.iboats.com/showthread.php?t=251571

Al Bell · Oct 26, 2008

Re: Mercruiser 140 stalls when I shift into reverse

Thanks for the links. I noticed that one of the cables from the shifter was not secured properly along with the other cables ( cable had fallen down along the gunnel). Would that be the cause of my problem?

chiefalen · Oct 27, 2008

Re: Mercruiser 140 stalls when I shift into reverse

One of the ties broke that hold it up?

Nope that's not the problem.

The shifter from the helm moves a converter that moves the lower shift cable that goes to the out drive.

Don just told you it's the lower shift cable.

If i were you i would believe him.

A lot of people think they can adjust it, may work once or twice but its toast probably need a new one.

Haut Medoc · Oct 27, 2008

Re: Mercruiser 140 stalls when I shift into reverse

Replace the lower cable.......

180shabah · Oct 27, 2008

Re: Mercruiser 140 stalls when I shift into reverse

Replace the cable now, or wait till memorial day weekend to do it instead of enjoying you boat with friends and family.

Bondo · Oct 27, 2008

Re: Mercruiser 140 stalls when I shift into reverse

I was told that it might be the shift interrupt switch. Does anyone have any advice on what the problem might be?

Ayuh,....

It's No Doubt the Lower Shift Cable needs replacing at least....

with a Mercruiser 140 inboard and Alpha one 165 outdrive.

It's also got the Wrong drive on it,....
That drive is geared for a I-6 motor,.....
The 140hp uses a 1.98:1 ratio,....
The 165s were I believe a 1.84:1 ratio, maybe 1.65:1...

Btw,.... It's Not an Alpha 1 either,.... It's a Mod. 1, or Pre-Alpha drive....

Al Bell · Oct 28, 2008

Re: Mercruiser 140 stalls when I shift into reverse

Bond-o,

What effect does the change in the drive ratio have in the overall performance/operation of the vessel. It currently has a 21" pitch aluminum prop and has a wot of 4700 rpm with full fuel and 2 adults.
Also, do you have any idea of what I should be paying to have the lower shift cable replaced?

Bondo · Oct 28, 2008

Re: Mercruiser 140 stalls when I shift into reverse

Ayuh,...

It would Appear, that the gears may have been changed in the drive, if you can pull a 21" prop with that load....

As for what it might cost to have somebody replace the cable for you,...
I really don't know...
I do most of my own work,+ barter with Buds to get done what I don't do.....

Al Bell · Nov 3, 2008

Re: Mercruiser 140 stalls when I shift into reverse

$510 dollars later my initial problem is solved but now I am having difficutly shifting in an out of gear (it does not shift out smoothly). I thought it was the idle to high but it appears the gears may be the issue. Any advice? Keep in mind the drive is not the original.

chiefalen · Nov 3, 2008

Re: Mercruiser 140 stalls when I shift into reverse

You should be between 650-700 rpm at idle in gear on the water.

Don S · Nov 3, 2008

Re: Mercruiser 140 stalls when I shift into reverse

(it does not shift out smoothly)

Please explain.

They do not shift like a car. There is some resistance, that's how they work.
But you could also have a faulty shifter unit, or a bad cable between the shifter and the engine. YOU, have to know what is right and what is wrong. Sorry, but we can't feel how it shifts.

ziggy · Nov 3, 2008

Re: Mercruiser 140 stalls when I shift into reverse

this is a interesting read. it explains what takes place when you shift... http://forums.iboats.com/showthread.php?t=169865
post #3...

Mercruiser 140 stalls when I shift into reverse

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