1970-72 mercury thunderbolt 800/80hp sn:2886778 no spark

Joined
May 31, 2009
Messages
7
hello there...... i have a few questions for anyone who can help me?

1970-72 mercury thunderbolt 800/80hp sn:2886778 no spark

ok well ibought the motor from someone who said there was no spark. the first thing i did was replace most of the wires as i knew they would be corroded and i attemped to start it again and once again no spark. no w i was told the engine was stored for a number of years so i was thinking i have to do the magneto and clean it up does anyone else have any options i also checked the distributor cap and everything looked fine???
 

rtpassini

Chief Petty Officer
Joined
Nov 27, 2008
Messages
508
Re: 1970-72 mercury thunderbolt 800/80hp sn:2886778 no spark

hows your battery?

go to the faq forum on here and look up some of the how to's
 
Joined
May 31, 2009
Messages
7
Re: 1970-72 mercury thunderbolt 800/80hp sn:2886778 no spark

the battery is fine i have an elimnator booster pack trying to start it
 

Moody Blue

Captain
Joined
May 24, 2004
Messages
3,136
Re: 1970-72 mercury thunderbolt 800/80hp sn:2886778 no spark

No spark
- check that there is 12V on both RED and WHITE terminals of port side of switchbox with key in run and start position
- battery must be in good condition. A weak battery will not start this motor. MUST be 9V minimum on those terminals when cranking.

Here are a few pages on troubleshooting the battery CDI ignition systems

http://outboardparts.com/mercury/troubleshooting/troubleshooting8.htm

http://www.boatpartstore.com/page18.asp

http://www.maxrules.com/cdi/TroubleshootingGuide.pdf
(scroll down to Merc Battery CD ignition system)
 
Joined
May 31, 2009
Messages
7
Re: 1970-72 mercury thunderbolt 800/80hp sn:2886778 no spark

i treid today and i am getting 12v off both terminals and i followed the troubleshooting and didnt work either. i think it might be the coil any suggestions....need help!!!!!!!
 
Joined
May 31, 2009
Messages
7
Re: 1970-72 mercury thunderbolt 800/80hp sn:2886778 no spark

the terminals that are supposed to have 12v have it is what i meant

i just replaced the switchbox, checked the coil and i am still getting no spark i found out the rectifier is all messed up the seal has been broken and it is corroded will that cause no spark????
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Re: 1970-72 mercury thunderbolt 800/80hp sn:2886778 no spark

The rectifier plays on part in the ign system on that motor. Ohm out the coil. it should have 1 ohm or so on the primary and several hundred ohms on the secondary. The plug and coil wires screw into the dissy cap. They pull out of the coil.

Run the Battery CDI test to see what is wrong, but if you have a known good switchbox, and good wiring, it is either the coil or the dissy trigger.
 
Top