What is the equivalent of miles on a car vs hours on an outboard engine?

Question

Usually when you go to buy a car you worry about the milage and on a boat the hours the engines have run. How can you compare the two? Does 1000 miles equal 100 hours on a boat?

Answer 1

Strictly, you can't.

If a car can do 100,000 miles before its engine needs a rebuild, and a boat engine runs for 1000 hours before it needs a rebuild, then you have a relative scale.

Excepting that I wear rally car motors out in about 40,000 miles of daily drive and competition; but taxis (cabs) can comfortably do 250,000 miles plus on the original engine.

So no, you can't; but the industry will know what a reasonable number of hours for an outboard motor is, per size and stroke.  Then you get the scale to work with in terms of value.

Answer 2

I don't think it's a question of miles versus hours, but more a case of how well things have been looked after.  I've seen some outboards that are far older than the average car that are still going strong, and with proper care and servicing there's no reason why they shouldn't continue to do so.

The main problem with outboards (in the UK anyway) is that they're laid up for about 5 months of the year and the innards tend to corrode if not properly corrosion-inhibited at the end of each season.

Answer 3

There is no correlation between the two.

You just have to think about what you would do with the boat.

For me…I take my boat out one day, most weekends…say 45 days a year.  And where I fish is about 1 hour away from home.

Then add on the the trolling that I do occassionaly.. say another hour every second weekend, so another 23 hours.

Remember... most of the time you are fishing, you are not running the engine...it is just getting to the fishing spot.

So yearly, I run up 67 hours.

Answer 4

No. There's no possible direct correlation.  Nor, do the other measures that you mention mean much.  I've heard engine hours, for years, but as a marine mechanic I can tell you they  are meaningless in determining the condition of the engine.  I've only seen one engine in over 30 years that came anywhere close to being worn out.  Maintenance Varies by the engine.  I've seen engines that weren't  "broke -in" that were 3 years old.  Then I've seen perfectly clean oil in five year old engines, that had been changed at the "20 hour" service.  So, I'd put little faith in any of the measures I've heard.  What matters is the condition of the engine.

Answer 5

there just isn't any correlation at all.

a lot of car engine's run time is spent loafing along the freeway at 1200 or 1500 RPM, with plenty of coasting.

Boat motors have to lift the hull out of the water and hold it there.  While pushing water out of the way.   It's why boats don't have transmissions.  They need the torque just to stay on plane at cruising speed.  Most outboard hours are probably at 4000 to 6000 RPM.

The analogy is, leaving your car sitting out on the street for weeks, then taking it out & driving it uphill 100% of the time, always in low gear.

My '79 vintage johnnyrude triple runs as good now as the day it was built.

Answer 6

it just gives you something to go by

like if you by a car with 100000 miles you know its used alot  by a motor with 1000 hrs  same thing  gotr it