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I have a yamaha 50 hp four stroke motor and was wondering if using another type of 4 stroke oil would harm the motor.

The manual just says 4 stroke oil.

If it was under warranty I would probably buy the yamaha oil but its so much $$$$$ and the motor is no longer under warranty.

Anybody use other types of oil in their 4 strokes and if so which brands. Are they cheaper?

Thanks

DH

Can't wait to head out on champlain for early lakers. GET WARM!!!!

No sure if you "have" to especially with out of warranty.

I do know making a engine happy means feeding it some AMSOIL
http://www.amsoil.com/StoreFront/wcf.aspx

I have used AMSOIL for years in everything, chainsaw, weedwacker, dirt bike (2 & 4 stroke), snowmobile, ATV.

Even right now I use the HP injector for 2 stroke oil injected outboard. Never used the 4stroke marine oil but can't see why its not as good as their other products.

However I think you will find that the Yammy oil is not that expensive compared to other high quality 4 stroke oils.

Thanks MDEJ

I guess its not that expensive but there is only one dealers around that carries it and it 40 minutes away.

Thanks again

Dh

All motor oil has an ASE Rating on the bottle. All motor manuals tell you what Spec ( ASE rating) to use. In the USA it is illegal for any manufacture to "require" the use of their oil only for warrenty purposes. Any oil meeting the specs is fine. Synthetics do offer increased benifits, But proper change intervals work just fine. Gussser

Any water rated oil with the correct SAE will be fine. Look for FC-W (Four Cycle - Water) just like you would TC-W (Two Cycle - Water) for a 2-stroke. There's not many out there yet but they will become more popular. Water rated oils have rust inhibitors and and are more tolerant of a bit of water getting in.

If you're not already aware, you can go to your nearest motorcycle dealer instead of a marina to get your oil. Might save you some time and miles.

Thanks Lunker Larry!

ady hit the nail on the head. These engines are operated in a marine environment and your typical engine oil in designed for a CAR engine not a BOAT engine. Also when do you ever get in your car and start it, warm it up for a few minutes and then go WOT for 30 minutes and more. Look at the average RPM of a car and it most don't rev pats 5000 rpm. This is where the outboard just starts to come alive. Now if you think the average mnotor oil can stand up to this type of use the answer is it can BUT FOR HOW LONG.

Oil is used to lubricate and hold combustion by-products for a specific period of time and then it becomes an an abrasive and it gets acidic and etches metal parts and bearings. Now what do you do after you have had you fun for the weekend you park the boat for a week and let it sit. Not like a car which you use mostly everyday. That sitting lets the condesation accumulate in the engine and allows the oil to do its nasty work on the engine components. Then next weekend it lousy and you don't go out so it sits another week. The oil keeps the bad stuff from eatting the metal and the better the oil the better the protection.

I'm at the checking out synthetic motor oil for marune engines but as of yet not even the manufacturers like mercruiser nor volvo-penta are recommending them yet. One of the reasons is the water thing. The closer to water the more corrosion you are subject to. Thus the better the oil the better the protection. Merc I/O motor oil is very high in detergents and thus a very good oil for that application. What I recommend is you use use the manufacturers oil if you can and if you can't get AT LEAST a good brand name oil like quaker state or castrol, etc. Interestingly there are only about 4 or 5 manufacturers of oil and shell is the biggest for making oil for companies like merc and brp and yamaha. I bet yammmy oil is made by castrol it used to be when I road raced.

My 550gpz would rev to 9,000 rpm and during the race never went below 5,000 rpm. After each weekend I would change the oil and filter just because of the abuse the oil would take.

So they words of advice are oil is the lifeblood of your engine and if you short change the oil you will ultimately short change the life of your engine and for the price of an new motor a few dollars spent now on the short end will save thousands. Pay me now or pay me alot more latter. I loved that fram commercial.

This is my concern with 4 stroke motors as marine outboard engines. My experience with motorcycles showed me the lack of control a normal human being has when it comes to breaking in a new motor. It's hard to control the throttle hand for an appropriate time to let all the components properly wear in. Because of this some engines with less than 2000 rpm would burn oil. This has been apparently addressed by the manfacturers through technology. Better metals, different honing procedures etc, but what is not adressed is the condition of a 4 stroke motor after 5 years of abusive usage. It will be a dirtier burning engine than some carburetted 2 strokes and will pollute more because it is a 4 stroke. With catalytic convertors the by-products will be exhausted into the water.

And another way of looking at it, is it will keep me busy rebuilding motors, so there is always a shinny side to everything.

Like Bob Marley said: Don't worry,
bout a thing,
cus every little things gonna be alright