Mercruiser 470 cuts out in reverse

[istapf]

The engine of my 1978 Mercruiser 470 IO dies as soon as it is put into reverse. It doesn't stall, the ignition is killed. I have looked at the Shift Interrupt Switch which grounds the point side of the coil, and don't understand its purpose. That seems to be killing the ignition in reverse.

 

[Don S]

Re: Mercruiser 470 cuts out in reverse

Sounds like you are due for a new shift cable from the drive to the engine.<br />Common problem with Merc Alpha drives. Replace the cable and you will be good as new.

 

[istapf]

Re: Mercruiser 470 cuts out in reverse

But what is the purpose of the shift interrupt switch? Why does it ground out the ignition?

 

[Haut Medoc]

Re: Mercruiser 470 cuts out in reverse

It kills the engine momentarily so that the gears in the drive are not under load when engaging/disengaging, esp. disengaging, don't go disconnecting it to get around your problem. Do what Don says & replace the cable & you will be good to go....JK

 

[istapf]

Re: Mercruiser 470 cuts out in reverse

Many thanks. I'll work on it. Irv

 

[Bondo]

Re: Mercruiser 470 cuts out in reverse

BTW,...........<br />The Interupter works Only coming OUT of gear,........<br /><br />That's Your Problem,........ The Cable is Too Stiff,+ is causing the switch to work going Into gear.........<br /><br />Another BTW,.......... Lubing the cable will Not Work,.... Replacement is the Only Fix.........