1987 omc 4.3 cobra (motor oil)

[tat2u]

I'm trying to figure out what oil is best for my boat. i called the local shop and they said that all there boat run 20/40 and my book say sae 30 and that multi viscosity is not recommend. i live in Washington state and fish the Puget sound and usually its in the 40 in the winter.

thanks aaron

 

[Bondo]

Re: 1987 omc 4.3 cobra (motor oil)

Ayuh,... Whatever oil you wanta run in it is Just Fine.....

 

[Howard Sterndrive]

Re: 1987 omc 4.3 cobra (motor oil)

I've never seen 20W40, but 20W50 would be fine.
25W40 or straight 30 also good choices.

 

[Gary H NC]

Re: 1987 omc 4.3 cobra (motor oil)

Straight 30 weight can be found in the gallon jugs at most auto parts stores.
Any truck stop will sell it also.
I used to run the Shell Rotella T Diesel oil in my old Cobra.
It is a good heavy duty oil and about 12 bucks a gallon.

 

[proshadetree]

Re: 1987 omc 4.3 cobra (motor oil)

I have found my oil pressure to be lower by about 10 psi on 30w !0/30 it will idel at 20 psi all day long. If this is a factor you might consider multi-viscosity oil. We run 30w in forklifts and some old high hour units have been changed to 10/30 or 10/40.

 

[Gary H NC]

Re: 1987 omc 4.3 cobra (motor oil)

I have found my oil pressure to be lower by about 10 psi on 30w !0/30 it will idel at 20 psi all day long. If this is a factor you might consider multi-viscosity oil. We run 30w in forklifts and some old high hour units have been changed to 10/30 or 10/40.

Straight 30 weight should actually run a little higher oil pressure than 10w-30,It is a thicker oil than any 10 weight multi viscosity oil.
My old Cobra was the opposite,lower pressure with 10w-30...

Either oil will be fine....just depends on what makes you feel better.Myself,if the book calls for straight 30 then i try to run it.

 

[proshadetree]

Re: 1987 omc 4.3 cobra (motor oil)

Wow thats strange. On the boat or several forklifts I have a noted improvement with the multi-viscosity oil. Normally 10 psi or more. Operating temp and manual gauge. 30W when hot is extremely thin. Just goes to show some engines like somethings and some the other.

 

[etracer68]

Re: 1987 omc 4.3 cobra (motor oil)

I have to agree with Gary on this. 10w-30 is a 10 weight oil with viscosity protection of a 30w.

 

[Lou C]

Re: 1987 omc 4.3 cobra (motor oil)

Like others said, you can use a variety of oil viscosities, straight 30 is what OMC recommended, but for the same engine, Merc recommended 30 below 50*, 40 above 50*, and perfers their 25/40. Volvo has recommended 20w/50 and straight 30 syn. I'd use straight 30 in cooler temps and straight 40 if your summer temps are hot.

 

[HT32BSX115]

Re: 1987 omc 4.3 cobra (motor oil)

I called the local shop and they said that all there boat run 20/40 and my book say sae 30 and that multi viscosity is not recommend. i live in Washington state and fish the Puget sound and usually its in the 40 in the winter.

thanks aaron

Hmm......we went almost 2 weeks without an oil thread (was there one last week that I missed?)


Just run what your "your book" says to run............ Or run what the local shop said to run......Or swing on over to Walmart and get anything they have on the shelves........you won't be able to tell the difference.


The above answers are what you'll get when you ask on this forum, or any other forum on the internet. We usually get one oil thread per week.... (did I somehow miss last weeks thread?)

What I use is in my signature below.....


Cheers,


Rick