how many hours on a boat engine is acceptable
Re: How many hours are too many? 25 to 50 hours per year is average useage in my area. 424 hours in 12 years seems fine. 1500 hours would mean rebuild time if the engine is well looked after. not exactly a rare boat with rare features, so if the price doesn't beat others with lower hours, move on.. there's no shortage of low hour boats. of course, not many 18 footers have hour meters.
Once again if you are asking about a 2-stroke motor the following does not apply. If the motor was properly maintained you should expect the life expectancy of gas-power 4-stroke marine motor to be between 1000 and 1500 hours. Or, another way to think about it that every 100 hours is about 15,000 miles. Once again this is just a rule of thumb and many variables affect this range. If you are in the market for a used boat then I will also suggest you consider a marine surveyor: http://www.marinesurvey.org/ .