Mercruiser 470 Engine Stall While In Reverse

[kyddvicous13]

It shifts and accelerates in forward with no problems. It shifts into reverse fine, but once I try to give it some throttle the engine stalls. Not sure if its related but the throttle control moves about a quarter of the way to shift into gear, then it will accelerate after that. Its a 79 mercruiser 470, 190 hp with a MC-1 pre alpha drive. Any suggestions would be greatly appreciated!

 

[bondo]

Ayuh,.... Welcome Aboard,...

My 1st guess is, the lower shift cable is draggin' causin' the stall...

Is the Shift Switch movin' as you advance the throttle,..??

If so, replace the lower cable...

 

[kghost]

The shift interuptor is the name I think Bondo was referring to.

There are two cables that are mounted on your shift bracket. One is from the shift control. the other is a short cable (short shift cable) that goes out the transom assembly and is what shift the outdrive.

If and when that short cable either wears out or get overheated then it creates resistance and causes the shift interuptor switch to be engaged. This typically happens when shifting into reverse. just the nature of the beast.

It could also be linkage in the gimbal housing so some diagnostics should be performed.

First you must understand, when shifting out of gear (ONLY) the shift interuptor switch will be engaged to momentarily kill the ignition so the clutch dogs in the lower unit will come apart. After this occurs the V notch will return to its home (center) positon.
If the switch did not work you would have to shift past neutral to get it out of gear. The resistance in the cable causes the V notch to move and engage the micro switch arm.

Does this make sense?


1. did the motor over heat recently?
2. do you know when the last time the cable was replaced?
3. di you or someone else mess with the cable adjustment?