Royal Purple Motor Oil

4020guy · Nov 12, 2014

Would Royal Purple API say 10W40 be a good choice for small 4 stroke engines? Have some 5hp Hondas and a 23hp Kawasaki in a JD 320 lawn mower. I use JD Plus 50 15W40 in most everything else. Just wondering.....Ron

Mike M · Nov 12, 2014

I'd just use the JD 15w40 oil in all of them since you have it. I run 15w40 Rotella in my mower and tractors. Works fine and is easy to find and cheaper than most to buy.
I knew of 1 guy that ran royal purple in a Cadillac with the 4.9 engine and had good luck with it and put a ton of miles on it. Think he may of went 10,000 mi at least between oil changes.

dej(Jed) · Nov 12, 2014

(quoted from post at 10:55:17 11/12/14) Would Royal Purple API say 10W40 be a good choice for small 4 stroke engines? Have some 5hp Hondas and a 23hp Kawasaki in a JD 320 lawn mower. I use JD Plus 50 15W40 in most everything else. Just wondering.....Ron

I ran the API oil audit testing program for a number of years and Royal Purple performed well.

DeltaRed · Nov 12, 2014

I'm with Mike.Use the JD oil. You already have it.And it saves you from have multiple oils around.I use the same motor oil in all my engines/From lawn mowers to autos/trucks to gas/diesel tractors to combines........Have for years.Never had a problem.

Jason S. · Nov 12, 2014

(quoted from post at 18:55:17 11/12/14) Would Royal Purple API say 10W40 be a good choice for small 4 stroke engines? Have some 5hp Hondas and a 23hp Kawasaki in a JD 320 lawn mower. I use JD Plus 50 15W40 in most everything else. Just wondering.....Ron

Be careful on that. I know when I worked for a small engine shop in the 1990's if you ran 10w40 in a Tecumseh engine it voided the warranty. I don't know if there are any others like that or not.

RyaninKS · Nov 12, 2014

I run it in my motorcycle...put about 8000 miles on it between oil changes which is about 2 riding seasons for me. I do however put a new filter on at the beginning of each season cause they're cheap and easy to get to.

Texasmark1 · Nov 13, 2014

I remember the cautions on 10w-40 also. Said that the
additives required to get that kind of a viscosity span were
excessive and that there wasn't enough oil left for proper
lubrication.

Course that was then and we are here now. If I can run 5W-40
Rot. T full sin in my Cummins diesel with the blessings of
Cummins (I asked them) then things must have changed.

So I don't know what to say. What's the oil worth to you and
what's the engine worth? Worth the gamble? Your money, your
equipment.

Mark

Royal Purple Motor Oil

4020guy

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Mike M

Well-known Member

dej(Jed)

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DeltaRed

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Jason S.

Well-known Member

RyaninKS

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Texasmark1

Well-known Member

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