testing switchbox 68 Merc500 50Hp

[RobG]

Hi everyone,

I would like to find out what is the procedure for testing the switchbox and related items on a 68 Merc500 50HP s/n 2477646. I am not getting any spark on the spark plugs. The switchbox number is 333-3213a3. The wire colors are Red, Blue, White, Green and Black. Is this similar to a headlight relay or something totally different?

Thanks

Rob

 

[Laddies]

Re: testing switchbox 68 Merc500 50Hp

Your engine is a 69 with driver CD ign. there is no tst for the switch box, it's done by testing surrounding componets so this is the process
1 Diconnect the orange wire at the switch box, if you have spark now the troble is in the kill circurt--switch, harness or tilt switch
2 Ck. driver with a OHM meter
RED TO WHITE----------400ohms--or 180+ volts with a DVA
BLUE TO WHITE---------10ohms---or 20+ volts with a DVA
GREEN TO ENGINE GRD.--N/A-------or 150+ volts with a DVA
White is a common wire for driver only (don't connect to engine grd)
All volts are read at crank speed with a DVA min of 250 RPM
If the system passes these tests and there is no spark or no spark to 1 or2 cyls ck the cap

 

[RobG]

Re: testing switchbox 68 Merc500 50Hp

Thanks Laddies,

I will do this tonight when I get home. I suspect that probably the wiring has rotted and would need to be redone. The harness itself has been redone and looks to be very crude with multiple splicing.

Rob