mercury 1000ss no spark at all

[scooba420]

trying to help a friend out on his believe to be 1968 mercury 1000ss id# 2411642 we got no spark at any plug or coil was wondering if a trigger could be the problem is there a way to test it or what else should we be testing for we have we got power and ignition at the motor so it cant be the ignition switch the problem started last season we took the boat out no issues next week we took the boat out and no spark it was the end of season here so we just winterized was messing with it today and when cranking the motor over with meter on the battery it was like just over 7 volts so I pulled all the plugs out put a different battery in well cranking it was at 9.5 volts still no spark will try and post pics later if that will help

 

[Laddies]

Re: mercury 1000ss no spark at all

Here's the test for the system

 

[scooba420]

Re: mercury 1000ss no spark at all

thanks will test it latter today and post results

 

[scooba420]

Re: mercury 1000ss no spark at all

ok so I did the test shown in the pic I get spark from the coil lead I then took of the jumper the ing to the hot wire put it back to stock turn the key and and did the test agin still have spark then I put the coil lead back in the cap turned the motor to #1 did the test agin and get spark at #1 so I think its the trigger that's bad but I still have to go through and make sure I get above 9 volts well cranking hoer the motor am on the right track so far thank for the help

 

[scooba420]

Re: mercury 1000ss no spark at all

anyone know what size battery this motor should use?

 

[Laddies]

Re: mercury 1000ss no spark at all

500cca no deep charge or maintaince free batteries

 

[scooba420]

Re: mercury 1000ss no spark at all

http://www.autozone.com/autozone/ac...nt/_/N-4ayyZ1z141xg?itemIdentifier=95824_0_0_

this is his battery its a starting and deep cycle battery is this ok my problem right now is that battery sits at 12.4 but when cranking it drops to 9.1 when cranking get very little spark out of coil lead when the trigger is bypassed and not cranking get lots of spark

 

[Laddies]

Re: mercury 1000ss no spark at all

The reason for not using any type of deep cycle battery is if the voltage drops below 9 volts it can kill the trigger and an unregulated charging system can surge the system and to much voltage will also kill the trigger. A good heavy duty battery takes the place of a voltage regulator by acting like a resistor. I cannot say if that battery will work as we never take a chance with one of these systems