Mercruiser Shif Interupt

[FreeBeeTony]

I have a pre-Alpha drive and gimbal housing that has a shift interupt switch. I am new to I/O's, it looks like this switch temporarily shorts out the voltage going to the distributor when shifting. I am assuming this is to unload the engine while shifting. A schematic I have calls out for a 'resistive' wire going from the key switch to the distributor. This 'resistive' wire will disipate the voltage drop when the short occurs when shifting(again I assume). I just purchased this boat ('78 Grady) and am rewiring it. It does not appear to have this 'resistive' wire. Can anyone help me in finding out the value of resistance required? I work in electronics, my thought is to install a resistor in series with the key switch in place of this 'resistive' wire, but I don't know what value to use. Any help would be appreciated.<br /><br />Thanks,<br /><br />Tony

 

[Trent]

Re: Mercruiser Shif Interupt

Normally if it does not have the resistance wire they use a coil with a internal resistor. Resistor (wire or coil) is used to drop the voltage to the points so they dont burn up as quick. Voltage leaving the coil (-) should be 9.5 volts.

 

[FreeBeeTony]

Re: Mercruiser Shif Interupt

I plan on converting to a HEI distributor. How does this change things?<br /><br />Tony

 

[Trent]

Re: Mercruiser Shif Interupt

Depends on which system you go for. Not much really.