hypothetical question on boat motors

[mrpike1973]

just wondering on a whole what causes the biggest demise of boat motors. considering in mn we only have about 5 months running time and there seems to be a lot of old motors from the 60's and 70's. do they just blow up, hit rocks. just wondering what happens to them i rarely hear someone say 'i believe we have to junk the boat motor because its to old'. any thoughts. on another note i think its great that old motors still run so good for the year kinda like tractors lots of old ih h's and jd a and b's around not many cars of that era around any more.

[Savage Brewer]

Well, I know when I was young I killed a old evinrude 2 stroke by not mixing in oil...

I also know a number of guys do severe damage with some of the older oil injected motors.

If I were to bet, I would think lubrication problems have to be #1.

[TruthWalleyes]

I blew one up with wayyyy to much seafoam

[20lbSloughShark]

I am actually surprised how long outboards last, as they run a relatively low amount of oil, and hold at a steady throttle at pretty high rpms (about 5000). Usually this is the worst possible combination of things for a 2 stroke, but outboards simply run forever unless you screw something up. Failed oil pumps (or forgetting to mix), or a failed cooling system are about the only ways to stop one.

[JohnMickish]

Outboards may run for years and years, but they do not acquire the hours or the varied temperatures that autos do. Not really an apples to apples comparison. Not a whole lot of outboards get started in -20 degree weather, and get asked to run for hours and hours at that temp.

[Savage Brewer]

I would have to agree, I dont think I know of any outboards being used at -20

[fasternu]

I was told today by a dealer that "many perfectly fine running outboars just get scrapped because there isn't a market for them". Of course, he said this as he was low-balling me while I was trying to trade in my 90 hp two stroke for a 90 4 stroke, so take it for what it's worth.....

[dan z]

Dealers flip motors for huge profits. I know from experience. My neighbor had his blow up(piston) well I blew mine up and took it to the same dealer and walla my neighbors motor was on the rack. I was interested in the motor so I had them run it and comp test it and out the door I go with it. They gave him $50 and had it serviced and on the rack for $495. They gave me 100 on trade for my blown motor. So there is money to be made on used motors.

[delcecchi]

Outboards may run for years and years, but they do not acquire the hours or the varied temperatures that autos do. Not really an apples to apples comparison. Not a whole lot of outboards get started in -20 degree weather, and get asked to run for hours and hours at that temp.

Isn't 200,000 miles in a car well over 4000 hours, typically? That would be average speed of 50 mph which seems on the high side for an average.

On the other hand, car motors don't spend much if any time at 4000+ RPM even if they do get started at various temperatures.

[BoxMN]

Are car engines the usual reason for a car to be scraped though? Seems like many time it would be a tranny or just plain too many fixes to suspension and smaller engine parts (radiators, etc.) to make it worth it to repair, when the actual engine might still be fine.

Similar to boat motors I would think. When they get old enough they just aren't "worth it" to purchase on a chitty old boat, and nobody wants an old motor on a new boat.

I can tell that my 31 year old Merc 50 is getting a bit tired, but it still starts great (first turn of key this spring), gets on plane with fat guys and decoys, and runs great, and I chuckle to think of how many hours are on that one Boy, did we used to troll all day with it back when it was new and before decent trolling motors.

[JohnMickish]

Isn't 200,000 miles in a car well over 4000 hours, typically? That would be average speed of 50 mph which seems on the high side for an average.

On the other hand, car motors don't spend much if any time at 4000+ RPM even if they do get started at various temperatures.

Your right, car motors are not designed for the high RPM that outboards are, but at the same time, for the price of the engine on my boat I can purchase a new car and have money left over for a vacation. If the engine in my car cost the same as the engine on my boat (about equal in HP) I'm sure it would go well past a half million miles with normal maintenance and still be able to go WOT for extended periods.

FWIW, 250 Verado Pro.

[delcecchi]

Yes, the price of outboards is somewhat ridiculous. I am presuming it is not due to manufacturing cost but distribution and markup.

A car produces profit to the dealer of a small fraction of the selling price, with a total markup over manufacturing cost+amortized fixed costs that I bet is small compared to that of an outboard.

My post was to show that car engines last a lot of hours, but I mentioned that lower stress could account for some of that.

[wastewaterguru]

#1 cause of ruined outboards in my mind is lack of use/neglect.

The ones I see that continue to run and run are the ones that are used the most.

Letting an outboard sit around too much is the worst thing you can do for one. For a used motor, I would always prefer a high hours well used and loved outboard to a sparkling 5 year old one with only 20 hours on it... and the cool thing is that you pay less for the motor with high hours anyway.