Engine Oil

[Gambit]

This topic has probably been posted before, but can I use regular car engine oil for my boat engine Mercruiser AlphaOne instead of marine oil? If so, what kind do you recommend? TIA.

 

[MooseHootie]

Re: Engine Oil

Most people do. I use full synthetic. The engine is screaming at 4500 rpms all day. I want good oil that will hold up to heat.

 

[beezee28]

Re: Engine Oil

What about using a straight 50 wt oil? Is it suitable or maybe 20/50 oil?

 

[crazy charlie]

Re: Engine Oil

Mercruiser recomends sae 30,thats straight weight.Car oil is fine as long as it is a quality oil. sae 40 can be used in warmer climates.I used sae 50 one hot summer a few years ago and it was fine except the upper motor was a little clackity for about 30 seconds upon a cold start so i figured it was a little too thick.Many here use synthetic but if there is any type of oil leak what so ever,there is a good chance that it will get worse.Charlie

 

[Bayrider]

Re: Engine Oil

I use 15W40 HD DIESEL engine oil.Works well on a high rpm Mercruiser engine.I think Mercruiser oil recommendations are a little outdated.

 

[Bondo]

Re: Engine Oil

Mobil 1 15W-50 for My boat........<br />Changed at every 50hrs.......

 

[Boatist]

Re: Engine Oil

Merc and OMC when around say use straight SAE 30.<br />I ask both at boats shows and both said the same thing. Their reply was the multi viscosity oils break down quicker then a straight weight and cars very rarely run at full throttle for long time like a boat. I ask even Synthetic and their answer was the same. For me I still use straight 30 motor oil and have had no reason to change but it I lived way up north in the cold I think I would try a synthetic 10-30. I do not run my engine full throttle more the 15 or 20 seconds either.

 

[Skipster1]

Re: Engine Oil

The type of oil you use also depends on where you are located. Down here in South Florida - where temps run at 90+ all summer - my 165hp InLine 6 cylinder NEEDS 40 weight, or 50. During the "winter" months (when temps drop down to 70-80 degrees) I can go back to 30 weight.<br />To be safe I'd use 10-40W. And MooseHootie might be right in suggesting synthetic. It is more stable at high RPMs.... tends not to break down under that kinda load.

 

[crazy charlie]

Re: Engine Oil

Thats bad advice Skiph!! 10w40 is not what anyone should use .Multigrade is NOT recommended for anyone or by anyone.The only exception to the rule I would consider is ,if it were a synthetic and thats only because some reputable members here use it.Charlie

 

[ken thrussell]

Re: Engine Oil

I use a 30 severe duty oil.....no problems and no clakkity clack

 

[lindb40530]

Re: Engine Oil

got a 5.0 omc 84. owned 20 years and run it hard skiing all day long. sae 30 is all I've ever used and never had a problem

 

[Peter J Fraser]

Re: Engine Oil

I'll add to the argument.<br /><br />For me its a 15w40 diesel oil CD or higher rating in everything I own. Petrol or diesel no matter. Synthetics OK also usually AMSOIL products.<br /><br />Peter