Oil 4 stroke Mercury 115hp

[Mc Tool]

A car engine may be capable of 280 HP.-----But it does not need near that output to move a car on a level road.----Put that car in neutral at 50 MPH and see how far it coasts.----Now try that with the boat.

If your trying to get me to say "thats not comparing apples with apples "...... Im not going to ......so there

 

[airshot]

I will add this.....go to the Eway and get on, leave your car in first gear and go cruise at 70-75 mph all day. Lets see how long your engine lasts. Then take your boat out for a cruise, but do not exceed the 2000-2500 rpm that your car normally runs at. Using this comparison, how long will your car engine last, and how enjoyable will your boat ride be ? That is comparing apples to apples......I don't buy the factory oils myself unless under warranty, but I do always use oils rated for the job/ engine I am using !

 

[Pmt133]

I'm in the "theres a spec and testing for that specs endorsement for a reason" camp. I've messed around and tested various oils in other applications and in most cases the manufacturer specs are the best for intended use. Straying outside that sometimes you had to get creative but we would get way way into the weeds if we go there.

Even at $200... it's way cheaper than fighting warranty.

 

[jimmbo]

There is a Spec, FC-W for 4 Stroke Marine Engines, just as the TCW-3 for 2 strokes. However that Spec is a Minimum, the low Bar for Oil Performance. I know that for Decades, the Outboard Engine Makers Oils, exceeded the TCW-* Standard, whist a lot of 3rd Party Oils met it, a few also Exceeded it, and some just barely squeaked by....
So some Auto/Truck Oils might indeed meet the Standard, but without Certification, it becomes an Expensive Crap Shoot, but everyone has the Right to gamble with their Engine

 

[Mc Tool]

I will add this.....go to the Eway and get on, leave your car in first gear and go cruise at 70-75 mph all day. Lets see how long your engine lasts. Then take your boat out for a cruise, but do not exceed the 2000-2500 rpm that your car normally runs at. Using this comparison, how long will your car engine last, and how enjoyable will your boat ride be ? That is comparing apples to apples......I don't buy the factory oils myself unless under warranty, but I do always use oils rated for the job/ engine I am using !

Yeah ok what revs is your boat doing at 75 mph.....all day, and anyhow its not about the revs . If you over rev anything it will blow up and if you under rev anything it wont make rated power.
If one of my motors needs 5w oil thats what it gets , doesnt matter if its peak torque is 4 grand or 10 grand ..,same oil . Fwiw I like Penrite hpr full synth in either 5w or 10w /40 extra 10

 

[jimmbo]

My Boat will do 67-68mph at 4800 rpm, I don't like to run it(5.7) for long at that Rpm cause it will shorten it's Lifespan Considerably.
The Engine that came in the Boat lasted about 110hrs. It ran those 110 hrs without any Oil Filtration, and sounded like it had a Solid Lifter Cam in serious need of a Lash Adjustment. Remote Oil Cooler Lines were hooked up Backwards, and the Check Valve in the Filter was very effective.... Engine was replaced under Warranty. 2nd Engine has about 500hrs on it, but hasn't been used much the last 10 yrs

 

[Mc Tool]

I think its more about what the engine is designed to do . An R1 yamaha has 200 hp (@13500rpm) at the wheel and is only 998cc , spec 10 or 15w40 full synth , a 225hp honda outboard is 3.6 L for about the same hp @ 5-6000 rpm and uses 5 or 10w30 .....it aint even about bhp / litre.

 

[jimmbo]

A 1 litre 4 stroke spinning 13,500 won't hold together many hrs.

 

[Mc Tool]

A 1 litre 4 stroke spinning 13,500 won't hold together many hrs.

Ha ha, bet it lasts longer than your 1st 5.7

Eat my shorts

 

[Lou C]

When evaluating oils for marine use, one thing I will notice is this:
after running the boat up on plane for a while, slow down, let the boat come off plane, bring it to idle, now what is your hot oil pressure? My sense is the better oils won't let it drop down as far, for example, at cruise you might be at 55-60 psi, at hot slow idle like 20-30, but if you're seeing like 10 psi, even though it's above the minimum for a Chevy small block, it shows that some oils hold their viscosity better hot than others. The other thing is that Mercury showed the differences with corrosion resistance their oil vs others, so maybe there is something to the marine certifications.
While I have said this a few times over the years, it bears repeating, do an oil analysis at the end of each season, then for sure you will know, is the oil you are using, staying in grade. Watching wear metals, you can also see this, looking at Al, Fe, Cu etc.
You'll also know if a problem is starting to develop, by looking at contaminates, like sodium/potassium (from antifreeze, if a closed cooled engine) or just sodium (if raw water cooled in salt water). I had this even before my engine overheated back in 2013, the head gaskets were starting to leak, but the engine ran as it always did and there was no sign on the dipstick or in the oil I pumped out that salt water was starting to get in.

 

[racerone]

Automotive engines are rarely asked to perform at full throttle / maximum power output for long periods of time.----The outboard is also subjected to " wave action " on the boat.----That can put high loads on the oil film between parts.