Outboard compairing car engine

mish · Mar 23, 2006

Hello, i looked for this topic, sorry not found.. I have just bought a Yamaha F100 from 2000, I don't know the history of the motor. But, i make a 'ride', and it feels very good and smootly. Can i compair the motor(the engine) with a car or motorbike(engine)? The displacement is almost 1600 cm3 (like a car). Here in Holland we can only make a trip in the summer. In the winter it is to cold. Let's say the motor runs 500 hours. The average speed of a car is maybe 50 km/u (30 miles at hour) When i translate the hours in km/ miles it is, 25000 km (16000 miles). I wonder if this is a right thought. Mzzl, Mish

PAkev · Mar 24, 2006

Re: Outboard compairing car engine

Mish, No similar comparison... At 30 MPH your car is probably pushing less than 2000 RPMS. At 30 MPH your boat is probably pushing 3500 to 4000 RPMS or better. Unlike automobile motors, marine motors are under a constant load to keep the boat on plane. Imagine it as always driving up hill in your car. In addition, outboards do not have a variable gear ratio such as which is afforded with the transmission in your automobile. Therefore, the gear ratio and prop combination offer the one "Best Overall" performance solution. Therefore, modern outboards tend to be a lot more technical (and expensive) than a conventional automobile engine. Driving your automobile at 4000 RPMS constantly for 16K miles will probably result in a compromised service life. However, with the proper care and preventive maintenance your outboard will continue to give you years of enjoyment.

JB · Mar 24, 2006

Re: Outboard compairing car engine

Hello, Mish. I think your logic is correct, but I think you very much overestimate the number of hours and engine is running during a short, summer season. If you use the engine (running) for 4 hours every day for three months you only run it 360 hours. I think 100 hours is a more realistic estimate for an engine used for a very busy season. That would be the equivalent of running you car about 3,000 miles.

mish · Mar 24, 2006

Re: Outboard compairing car engine

Allright, thanks for the information. 100 hours is indeed a lot for 1 summer. @ JB, my motor is 5 years old. Indeed 5 x 100 = 500 hours. Is that a lot for a outboard? I see each year several oldie's like a evinrude/ johnson/ mercury. These 2 stroke engines are at least 25 jears old. It must be extremly good quality. Are the 4-stroke those days the same quality? Thanks, Mish

Silvertip · Mar 24, 2006

Re: Outboard compairing car engine

Why not look at in terms of engine revolutions. A boat engine running at 6000 rpm is enduring three times the stress as the car engine at 2000 RPM. Figure out the number of engine revolutions in 150,000 miles and compare that figure with your annual boat use at say an average of 4500 RPM for the boat. Given both engines get the same care you should be able to extrapolate longevity within certain limits. The unknown here is wear rates. It's probably not linear so the boat engine is going to suffer more just because its a boat engine.

mish · Mar 24, 2006

Re: Outboard compairing car engine

Thanks for the information. Mish

JB · Mar 24, 2006

Re: Outboard compairing car engine

500 hours is not a lot for a well maintained outboard, Mish. The "average" life of an outboard has been pretty much agreed on as 1500 hours, but many exceed that by double or triple. I don't really look at an outboard as "old" until it is 35-40 years old and/or over 5000 hours. There are still a lot of outboards around 50 years old that are in daily, reliable service.

Silvertip · Mar 25, 2006

Re: Outboard compairing car engine

Doing the math (quickly), 4000 RPM average = 240,000 RPM/hr. Over 7000 hours that equates to a lifetime 1.68 BILLION RPM. A car at 60 MPH averages about 2000 RPM or 150,000 miles at an averages 2000 RPM/mile = 300,000,000 (300 MILLION) total RPM. Using those numbers, a 7000 hour outboard equates to a car with over 750,000 miles. I doubt you'll see many 7000 or even 5000 hour four-strokes. Will there be some? Certainly -- but they will be the exception not the rule. But then I've had to "eat my words before".

mish · Mar 25, 2006

Re: Outboard compairing car engine

Allright, when we compair the RPM, i got another number. The average RPM of my motor = 1500 rpm One hour = 90000 RPM Over 7000 hours = 630000000 RPM Lower number RPM, it's for recreation..

I think that the average speed of a car closer to 30 Miles is. Using those numbers, a 7000 hour outboard equates to a car with over 210,000 miles. But, when I use my outboard 100 hour each summer, the motor retired when i reach the age of 105 years old... Pfff It is a little bit compair cookies with candy's. But it is a indication. When I translate it to hours. 1 hours with the outboard is 30 miles with the car. Let say the car retired at 200000 miles. The outboard runs 4000 hours. That is close by the number JB called: 5000 hours. I think he is right. A motor runs with a good maintance between 4000 ~ 7000 hours. Maybe there is any difference between a 2 and 4 stroke? I am curious about this subject. I just bought a F100 Yamaha, 4 stroke. The motor is bought in 1999 and used fo the first time in 2000. 5 summers, I think 500 hours...I understand this is not a exeption.. Ps. sorry for my poor English, it is a long time for me to write English. I hope you can read and understand my words... Mish

rodbolt · Mar 25, 2006

Re: Outboard compairing car engine

its not all about the RPM. it has a bit to do with duty cycle as well. as the RPM increases the duty cylce of the reciprocating parts becomes greater. same as your truck in overdrive cruising down the flats is only producing maybe 20% of its rated output power. that F100 on a 19ft boat with 1000lbs of gear at 4500 RPM is producing close to 85% or so of its rated output. most automobiles have a transmission to keep the engine in a very specific RPM range, your outboard has to comprimise at all ranges up WOT. most outboards also have to deal with varying cooling water temps as well as periods of extended inactivity. the piston/rod assy from an F150 is a work of art. the rod has the beam shotpeened and polished and the skirts are cut beautifily. better than most the manley pistons we ever cut up. about the only mod I could make to that piston would be gas porting it but longevity of the ring/cylwall would suffer. so really there is no comparasion from the auto engine to a outboard 4 stroke powerhead other than engine family.

mish · Mar 26, 2006

Re: Outboard compairing car engine

Allright, thanks for the answer. Rodbolt, what do you think about lifetime of a 4-stroke outboard? Can I comparasion a 2 stroke outboard with a 4 stroke if it goes about lifetime? Thanks, Msh

rodbolt · Mar 26, 2006

Re: Outboard compairing car engine

dont overheat it, keep good oil in it and fresh fuel and service it like the manual says at the appropriate hours OR Calander. I have a few about with over 4000 hours and still cadilacing.overheat it and crack a head,gum up the fuel system and burn a valve, sling a timing belt and you will find what "interference type" is. if taken care of its a solid motor. abuse it and it dies like all the rest.

mish · Mar 27, 2006

Re: Outboard compairing car engine

Oke Rodbolt, Thanks! Good maintance is the answer. Over 4000 hours is a lot. Mhhh.

Mish

Outboard compairing car engine

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