Stupid questions about ignition components, 1978 70hp 3cyl

[ajgraz]

1978 Mercury 70hp 3 cyl.

I am awaiting a new set of ignition coils, everything else is in place and wired up on the powerhead (trigger, stator, switchbox, rectifier, internal harness; starter and battery power and ground, though ground currently disconnected at battery).

I'd like to get started on the initial (crank speed) timing settings (i.e., begin the link & sync process) while awaiting my coils. Already got my timing pointer aligned.

Stupid questions:

Will it damage the stator, trigger, or switchbox to crank the motor without the coils installed?

If so, will it damage the trigger to crank the motor with it disconnected from the switchbox? How about the stator if disconnected from the switchbox and the rectifier?

 

[Maxz695]

Re: Stupid questions about ignition components, 1978 70hp 3cyl

Hey bro how will you get spark to set timing with no coils? Arte you using an old coil on #1 Cylinder? I also cant see it damaging anything as the only spark plug you will be using is grounded in the cylinder. Just make sure the other wires are off the switchbox for the coils as not to ground out

 

[ajgraz]

Re: Stupid questions about ignition components, 1978 70hp 3cyl

Hey bro how will you get spark to set timing with no coils?

Good point, ha ha! Guess I haven't had enough coffee today, my brain is still stupid. Have to wait for my new coils to show up obviously.

 

[Maxz695]

Re: Stupid questions about ignition components, 1978 70hp 3cyl

sorry man I know the feeling wanting to get it going and all. But the switchbox may have a build up of current from not discharging and it may cause damage so I have a spare switchbox for you if it messed up

 

[ajgraz]

Re: Stupid questions about ignition components, 1978 70hp 3cyl

Haven't done any of this yet. Yes I can see where the switchbox can fry from stator voltage buildup.

Another stupid question: in the past while setting initial / cranking speed timing I have always grounded out #2 and #3 plug wires with jumper wires from inside the boot to the block. Even with alligator clips, sometimes those jumper wires come loose from powerhead vibration, accidental sweep of the arm, etc. Been shocked once, too. Do you suppose it's possible instead to simply "bypass" coils #2 and #3 by temporarily hooking up the green/red and green/white wires out of the switchbox to ground? Seems to me like that'd be one heck of a safe, secure, and easy way to effectively ground out 2 and 3, while still allowing the switchbox to discharge.

 

[Maxz695]

Re: Stupid questions about ignition components, 1978 70hp 3cyl

hooking up wires for coils from the switchbox to the ground would fry the switchbox. The positive lead from the switchbox goes to the coil pos and the neg to the ground the spark plug acts like a switch would. If you took a 110 Volt lead and put it to the ground it would trip the circut same thing only theres no circut breaker for the switchbox

 

[Faztbullet]

Re: Stupid questions about ignition components, 1978 70hp 3cyl

Haven't done any of this yet. Yes I can see where the switchbox can fry from stator voltage buildup.

Wont hurt a thing ..this is a old wifes tale. The reason you ground spark plug wires when testing is to keep spark from shocking you by accident and igniting a fuel charge ejected by cylinder when cranking with plugs out.