Lawn mower oil in Onan Generator

[BillJ99]

I've got an Onan 2800 gas powered genset in my motorhome. Onan recommends SAE30 oil when temperatures are above freezing and 15W40 if the genset might be used below 32F.
I've read that these motors have flat tappets and that shear could be a high wear factor. I'm thinking of using the following oils:

- During the active summer season, I would use Briggs and Stratton lawn mower SAE30 oil which is classified SJ.
- During the winter, since I want to exercise the generator every month, I would use 15W40 diesel oil, like Shell Rotella.

Anything wrong with my plan? Am I missing something?

 

[eljefino]

Sounds like a waste, putting a winter oil in just for exercising the gear.

I assume you want it ready in case of power outage or whatever. Otherwise you could use a block heater on that 30-weight to warm it up to exercise the generator. Or pick a nice day when it's above freezing for an hour in the afternoon.

The 15w40 should be good year round. Has lots of nice anti wear adds and runs in highly stressed 18 wheelers so should be good for your generator.

 

[Trav]

IS this the Subaru Robin engine EX21?

 

[Doog]

Rotella 15w40 all year

 

[toneydoc]

I agree with DOOG

 

[The motor guy]

That makes no sense. You sure you don't have it backwards?

 

[BillJ99]

No, I don't have it backwards. Here is a cut-and-paste from the Onan
owner's manual:

ENGINE OIL RECOMMENDATIONS
Use API (American Petroleum Institute) performance
Class SJ, SH or SG engine oil, which may be
in combination with performance Class CH-4, CG-4
or CF-4 (for example: SJ/CH-4). Also look for the
SAE (Society of Automotive Engineers) viscosity
grade. Referring to Table 1, choose the viscosity
grade appropriate for the ambient temperatures
expected until the next scheduled oil change.

Single-grade SAE 30 oil is preferable when temperatures
are consistently above freezing. Multigrade
oils are better when wide temperature variations are
expected.
TABLE 1. OIL VISCOSITY VS. TEMPERATURE
EXPECTED AMBIENT TEMPERATURES >>>>> SAE VISCOSITY GRADE
32° F (0° C) and higher >>>>>>>>>>>>>>> 30
10° F to 100° F (–12° C to 38° C) >>>>>>>>> 15W-40

 

[LargeCarManX2]

How about using a 0w40 year round?

 

[BillJ99]

Originally Posted By: Trav
IS this the Subaru Robin engine EX21?


No it isn't. Cummins Onan makes their own engines. The model number is GH-200.

 

[Gabe]

It looks like you are clearly in the 15w40 range. Mobil Delvac is a nice oil too.

 

[Trav]

Originally Posted By: BillJ99
Originally Posted By: Trav
IS this the Subaru Robin engine EX21?


No it isn't. Cummins Onan makes their own engines. The model number is GH-200.


I'm liking German Castrol for this engine. Here's why.
Its heavy enough to provide the protection of a heavy 30 weight yet will provide good cold start protection. It would be a good year round oil.
It is also SJ rated so zinc levels should be more than adequate for this engine.

 

[dave123]

Amsoil ASE 4stroke year round