tune up fits

[oldblumerc]

i have a 74 merc 140 im trying to tune it up, so i run it in the driveway with the muffs on set everything the way the book says timeing dwell ect... runs great so i shut it down and start i back up check everything again and call it good for the day. I take the baot out the next morning and it wont idle below 1000 rpms and it pings like crazy under a load i can figure this out, it happened just like that two weeks in a row

 

[Yepblaze]

Re: tune up fits

Sounds like the timing is advanced beyond spec.<br /><br />Check timing mark TDC against actual piston TDC to see if it is incorrect.