jbjennings
Captain
- Joined
- Jul 18, 2007
- Messages
- 3,903
Guys,
I've had this old 650 for a while now. When I first had it, I had intermittent problems with detonation chewing on pistons. At the advice of Faztbullet, I retarded the timing some and it since has given good service, but I've never been able to get a good steady idle. It's always seeming to lean when cold, and too rich when warm, etc.
I decided to pull the powerhead and change the lower crank seals today and clean the carbs, and reset the timing to factory specs and see how she ran then.
Question: How do you tell if the lower crank seals are bad? I noticed a big drop of quicksilver (green) oil on the seal retainer before I installed a puller and removed it. It appeared to be leaking clean 2-stroke oil. I didn't turn the flywheel and look for bubbles since it's so heavy and I've already got new seals and going to change them anyway.
Question #2: Is it more likely that a leaky crank seal or dirty high speed jets on the carbs are causing the detonation? I'm almost positive I have retarded the timing too much because the motor is sluggish now---just doesn't have as much power lately. I haven't had any problems with detonation in many tanks of gas.
Anyway, I'm changing the seals and rebuilding the carbs and will check back in with results. I would feel better if you guys thought the quicksilver 2-stroke oil on the crank seal retainer piece was a dead giveaway to a leak.
I hope you guys are doing well. I haven't posted on the merc forum in a while.
Thanks again,
JBJ
I've had this old 650 for a while now. When I first had it, I had intermittent problems with detonation chewing on pistons. At the advice of Faztbullet, I retarded the timing some and it since has given good service, but I've never been able to get a good steady idle. It's always seeming to lean when cold, and too rich when warm, etc.
I decided to pull the powerhead and change the lower crank seals today and clean the carbs, and reset the timing to factory specs and see how she ran then.
Question: How do you tell if the lower crank seals are bad? I noticed a big drop of quicksilver (green) oil on the seal retainer before I installed a puller and removed it. It appeared to be leaking clean 2-stroke oil. I didn't turn the flywheel and look for bubbles since it's so heavy and I've already got new seals and going to change them anyway.
Question #2: Is it more likely that a leaky crank seal or dirty high speed jets on the carbs are causing the detonation? I'm almost positive I have retarded the timing too much because the motor is sluggish now---just doesn't have as much power lately. I haven't had any problems with detonation in many tanks of gas.
Anyway, I'm changing the seals and rebuilding the carbs and will check back in with results. I would feel better if you guys thought the quicksilver 2-stroke oil on the crank seal retainer piece was a dead giveaway to a leak.
I hope you guys are doing well. I haven't posted on the merc forum in a while.
Thanks again,
JBJ
