I have been looking for my first boat and I think I am going to buy a new Z-6 from bass pro, but I have still been looking at used boats. How many hours is to much on a motor? I was looking at one boat that had 700. That seems like a lot of hours for a boat. What about compression, what is a correct PSI if the motor is running as should?

the hrs are not so important as the maintenance that was done and how regular, I have an 82 johnson 175 that runs better than new and carries 115psi on all 6 cyls.
if by what psi is correct you mean water press. it will vary with the engine brand, again my 82 has the press guage pegged at over 30psi due to the scoops I added to the pickups.
most will run in the 8-15 psi range I think, johnson/rude pick up the pressure before the water enters the head while a merc reads the in head pressure, not sure bout the others.
the engine comp should not be more than 10% different from hi to low or walk away, you want as little difference as possible on the compression.

very true. i had an 06 optimax with over 800 hours on it and it ran great. but there are always bigger chances of something going down on a 800 hour motor vs a 200 hour motor. regaurdless any boat motor will leave you stranded at any given moment! if you have the money, warranty is an exellent peace of mind.

used to be 2500 was considered a good lifespan on most outboards but im shure with the new motor technologies that has increased

God I hope so!

I think Ethanol the great savior of our planet might be reducing lifespan especially with 15% approaching�

In Texas, "normal" use will put about 120 hours a year on a motor.

I've had several I put well over 2,000 on, good oils and fuel will make a huge difference.

I did experiment one year, nothing but wally oil, that motor was wore out with 900 hours. Never again, you get what you pay for.

Im glad our boat motor doesnt have an hour meter on it... it would scare me, its been run hard since 1985 and still tickin... knock on wood!

The worst thing it has been through though is the last two years, we bought a ranch and the boat doesnt see the run time it used to, and I can tell, it is going to need a carb job in the near future.

matt

generally speaking, anything upwards of 100 is ok as long as all cyl are within 5% of the average. 95-95-95-95 is better than 130-130-110-125

I think in most cases 700 hours over 4 years is preferable to 100 hours in 4 years -- sitting around unused can be hard on machinery.