1975 mercury 650 65 hp no spark, please help

[bradhonker]

Hi my motor is cranking but I have no spark. serial #4139247. i replaced the switch box and my rectifier, still no spark. But the other day I got it started let it run for like 10 seconds then shut off, now again no spark. But it does sound like my motor wants to start when I let go of the key switch. I have tried starting it many times no but wont start. can someone help. ty

 

[bradhonker]

Re: 1975 mercury 650 65 hp no spark

Re: 1975 mercury 650 65 hp no spark

any help would be much appreciated, ty

 

[bradhonker]

Re: 1975 mercury 650 65 hp no spark

Re: 1975 mercury 650 65 hp no spark

what does the mercury switch look like? I cant find it, I see it on my wire diagram but cant find it in my motor, where is it located?? ty

 

[hawkf250]

Re: 1975 mercury 650 65 hp no spark, please help

Hey, I dont know if you got it figured out or not but just my two cents, I would check the stator, Usually if you loose fire on all cylinders it is either the switch box or the stator. Youve already changed the switch box, now check the stator. Hope this helps, also I would clean all wires and grounds

 

[bradhonker]

Re: 1975 mercury 650 65 hp no spark, please help

thanksfor your reply, I checked the white wire while cranking and im only getting 3v! what does this mean? I cleaned as many wires and grounds that i can see, still same thing, wont start