Old Merc

[taildragger101]

Could use some help. I bought a Merc 650 from a guy that said the trigger was bad. Has no spark. Took his word and bought a used distributor off a 76 650 they said it was running when they pulled it off. Put it on and still no spark. Any idea if the switchbox could be the prob. Any way to check the trigger.

 

[taildragger101]

Re: Old Merc

Update, just found out my engine is a 1973. Would the 1976 distributor make a difference?

 

[jbjennings]

Re: Old Merc

Was the distributor that came on the '73 bad?
If it were me, I'd take all the wires off the switchbox and clean the terminals with a brush. I'd also clean all grounds. Then give it a try with the original distributor after cleaning the rotor tip and getting the corrosion off that the arcing causes. I'm not sure if the '76 would work or not. Go to crowleymarine.com and look up the parts diagrams and see if the part numbers match.
I've had my switchbox stop working on my '73 and '74 650's and if I recall correctly, disconnecting the brown wire and cleaning the terminal and reattaching seemed to get it working right.
As far as I know, I believe your motor has a battery CD ignition with a distributor as you already know, and doesn't have a trigger. It does have a coil. Check to see if you're getting voltage at the coil as well. Don't run it on a battery that isn't fully charged.
Maybe Laddies or Faztbullet, or others that really know the mercs will post on your thread.
Good luck,
JBJ

 

[taildragger101]

Re: Old Merc

The guy i bought it from said it was bad. I dont know how to check it.I thought the trigger is the dist. housing.A guy on another thread just said my engine was a 73. Now i am not sure Merc 650 Serial# 3664707.

 

[taildragger101]

Re: Old Merc

Ok just went to crowely and the housing numbers match on the 73 and the 75. Wish someone could tell me how to check the dist. or the switchbox.

 

[taildragger101]

Re: Old Merc

Should there be voltage to coil-green wire that goes to bottom terminal on switchbox?

 

[Chris1956]

Re: Old Merc

Green wire likely is pulsed with voltage to induce spark. So you will not see a voltage. Go on the CDIElectronics web site and look up the troubleshooting procedure. Likely you can test everything but the trigger, thereby isolating it.