Is 10W-30 or SAE 30 same & Itming for octane 91 gas

idesign

Seaman
Joined
Jul 12, 2008
Messages
60
My OMC manual says SAE 30 for engine oil.My friend is recomending me putting Royal Purple SAE 30 oil.I am not able to find this oil here in Toronto.SO can i put Royal Purple 10w30 instead of straight 30 weight.Please let me know.Thank you
 

Shrub88

Seaman Apprentice
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May 24, 2008
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Re: Is 10W-30 or SAE 30 same & Itming for octane 91 gas

I am not able to find this oil here in Toronto.SO can i put Royal Purple 10w30 instead of straight 30 weight.Please let me know.Thank you

Look around for some Rotella 30W. Call your local auto parts stores, tractor supply and farm equipment stores, or any truck stop around you should have it.
 

Lou C

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Nov 10, 2002
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13,125
Re: Is 10W-30 or SAE 30 same & Itming for octane 91 gas

I would not use a mulit vis in a marine engine....my 21 year old OMC 4.3 likes Chevron Delo 400 straight 30 but you can also use Shell Rotella 30 or Pennzoil Marine 30 wt...the other option is the Merc 25/40 which is not a multi vis in that viscosity improvers (supposedly) are not used....but it's more expensive that the other choices....my 21 year old motor still gives 20 psi at hot idle (600 rpm) and 40-60 psi at running speeds....a conventional mult vis may thin out under marine use (3500 rpm constantly...)
 

jaxnjil

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Aug 3, 2007
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Re: Is 10W-30 or SAE 30 same & Itming for octane 91 gas

My OMC manual says SAE 30 for engine oil.My friend is recomending me putting Royal Purple SAE 30 oil.I am not able to find this oil here in Toronto.SO can i put Royal Purple 10w30 instead of straight 30 weight.Please let me know.Thank you



to answer your question; no 10-30 and 30 are not the same thing
you need the straight 30 because of the harsher duty cycle your boat motor is exposed to as opposed to a car
 

rbh

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Mar 21, 2009
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Re: Is 10W-30 or SAE 30 same & Itming for octane 91 gas

think of your motor as a generator rather than an automotive engine. unlike your car or truck which has a large transmission to keep your rpms to a minimum you boat basicly has two gears forward and reverse of which can only increase speed buy more rpms.
so your running down the lake for an hour at 3800 rpm, you need a good thick oil.
old spects 30 weight (detergent)
new spects 25/40
your choice, just dont mix them unless your in a pinch.
rob
 

CAPTKEV85

Petty Officer 1st Class
Joined
Mar 12, 2008
Messages
229
Re: Is 10W-30 or SAE 30 same & Itming for octane 91 gas

Rotella is a deisel oil it has a detergant in it to clean the carbon build up off the cylinder walls. This will kill you rings in the motor. Stick with the manual 30 weight is avail anywere. I use valvoline and I run for 2 hours straight and still have 20 psi when I idle.
 

gadget73

Petty Officer 1st Class
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Jun 20, 2009
Messages
308
Re: Is 10W-30 or SAE 30 same & Itming for octane 91 gas

I wouldn't be so concerned about using specifically Royal Purple. Thats a synthetic oil, more designed for high performance motors. Standard 30 weight will do you fine, it gets changed yearly anyway so it should be fine.
 

JustJason

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Aug 27, 2007
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5,321
Re: Is 10W-30 or SAE 30 same & Itming for octane 91 gas

I wouldn't be concerened about the actual brand name, as long is it was a quality brand name. Ie.. No wally world labeled oil.
 
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