I know this has been asked before.

[Y-Not]

But I CAN NOT FIND IT!!!!

I have a 2004 merc 90 hp carby 2 stroke motor. I have put 650 hours on it so far, but how many more can I expect before I need to re-power again? I replaced an old V4 115 johno with this motor after it had 1800 hours on it. this motor does not seem as strong and I don't expect the same life or am I wrong on this one?

[Jarrah Jack]

So many variables with motors. Has it been proped right its entire life?.... Can make a big difference. Also flushing and general maintaince are important. Has it had an easy life or been flogged? If alls good then there is no reason to believe you won't get many many more hours.

[TheRealAndy]

I reckon you will get the same hours unless you never maintain it.

[Y-Not]

Flushed for 30 mins after every trip 10 mins with the motor idling and 20 mins just on the flush feed. serviced every 12 months or 100 hours whchever comes first . (think once it was at the 12 months :) )

Rarely taken near WOT occasionly just to blow the carbs clean but never for more than 10 to 20 seconds. this has been maybe 4 or 5 times over the tears normally cruise at about 4100RPM gives me about 20 knots and that's enough.

[Steeler]

Nothing to worry about, once you've had black you never go back.If a marine mech is servicing it for you is he doing a comp test at each service ?.

Those things are good for many many hours and only start getting tired when about mid 90's PSI across all cyl's.

[Y-Not]

Yes serviced by marine tech each time need to look at the service records to see where comp is at though.

[Steeler]

Dealer mate of mine does this first, not much point spending a packet on a service if comps are up the pooh pooh.