2003 25hp wont start

[Killer whale]

I have a 2003 25 hp EFI mercury, electric start. It will start sometimes and then other times have no spark. Very sporadic. Any suggestions on troubleshooting.

 

[AllDodge]

Folks are most likely need more info about your motor like the serial number to be able to provide accurate response.

I would start with measure fuel pressure with key ON motor off, and also when running

Next measure power at the coil(s) to see if it remains with key ON and while cranking

 

[Stressfree]

Before you do anything take the cover off and push on timing belt went nuts with mine did everything YouTube told me timing belt ready to fall off good place to start