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FJB20
05-07-2002, 09:36 AM
What is considered a lot of hour on a boat ?? Is there a formula to equate hours to a boat -Miles on a car??
Just looked at a 1999 Donzi with 166 hours on it.
Is that like 30,00 miles on a car. Thanx !!!!
FJB20

RickSE
05-07-2002, 12:16 PM
FYI, My truck has approx. 350 hours on the motor at 10,500 miles. 166 hrs. doesn't seem like much to me, that's about 5,000 miles if you use my numbers, HRS. x 30mph. But boat engines are certainly run harder than auto engines. I have heard of people though with 1,000 hours on a marine engine.

Ranman
05-07-2002, 12:47 PM
The number of hours a marine engine will last relies on many variables. How much boat the engine is pushing around (load), wide open time vs. cruising time, how well it was maintained, etc. My first Donzi had 330 hrs on it and it ran like a top. I would say rebuild time would usually come between 500-100 hrs, though that's a big window.

Here in Michigan, our general rule of thumb is 100 hrs / yr is average. I would consider 166 hrs to have been used just over a year and a half (in MI at least). Any whoo, that's not too many hours in my book. Randy

RPD
05-07-2002, 09:17 PM
Actually, boat engines are run very differently than the same engine in an auto.... when you let off the gas in a car, the momentum of the car pushes against the engine resulting in a braking effect... when this occurs the force on the pistons changes, the pistons cock over, and there is continued wear causing the cylinder to eventually be somewhat oval... in a boat there is no "engine braking" because when you let off the gas the propeller does not provide much force into the engine.... also, boats are run at a constant speed much more so than cars and trucks, many are run on autopilot for hours at a time... thus, engine wear is often less of a problem on a boat than in a car.... rust and corrosion are more likely the undoing of a marine engine (I live in a saltwater locale).... THEN we come to Donzis which may experience frequent full throttle acceleration from an idle, may experience sustained WOT, and may be found jumping waves with the result that the oil pickup is intermittent.... under such conditions an engine might wear quite rapidly.... so the answer to your question lies in how the boat was treated.

Bryan Tuvell 33ZX
05-07-2002, 09:53 PM
HHHmmmm, most of us in the HRPA average 150+ hours a season... 200 for me last year.
I have had the new boat out 8 or 9 times and I am at 60 hours.
One ZX Donzi in our club had 182 hours in 6 months this past year (go DMAN!)
I personally think there is no comparision between hours and miles. Follow the maitenance schedule and flush like crazy EVERY time with salt away, cross your fingers and hope for the best.
Bryan

Stix Magill
05-07-2002, 11:22 PM
FJB,

I have been told that the marine motor is under constant strain when it is underway (there is little to no coasting as there is no downhill) and therefore wears differently than automotive, and in the opposite manner described above. Isn't that why marine motors are built "over" automotive engines?
Also I have been told (who are these people?) that the way to view the wear on the engine is not the miles, but the hours/rpms. This sounds right to me. If you run at WOT and your RPMs are 4800, compare that to your car at 4800 rpm. You would not expect to run at redline forever without engine wear.
I have always like to cruise at 50 to 80% of WOT to extend engine life and also to have a little extra to throw their heads back!
:D Anyway, under 200 hours on a motor that has not been abused shoud be fine. Have fun!