Briggs and Stratton oil consumption

Briggs & Stratton generator troubleshooting
78buckshot
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I switched over to Valvoline GEO Premium Blue Natural Gas oil for one of my Generac liquids, it has had a good result. It is the only oil recommended by Cummins/Onan for the Ford V10 6.8 litre. I service two of the Cummins. The Valvoline is a 15W-40 and I don't know if it comes in any other weights.
Chris
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I didn't know Cummins Onan was using the Ford 6.8L too? That's kinda cool that not only Generac is using that platform. Must mean something! Haha!
Generac tech for over 12 years. I'm here to help!
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78buckshot
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I don't know what other engines they use other than their own, we do HVAC work for Google in Ann Arbor, they have a V10 60kw and another one on the roof with a converted Cummins both running on natural. On the ground they have a 250kw with a Cummins 14 litre 6 cylinder converted to natural gas, that engine has been their mainstay in the trucking industry for decades. Pretty impressive equipment.
Chris
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Very cool! I don't see anything much other than Generac and some occasional Briggs and Kohler, but those are rare for me.
Generac tech for over 12 years. I'm here to help!
"The only source of knowledge is experience" -Albert Einstein
Looking for Generac parts? Gentek Power offers the full line of Generac replacement parts! Shop Gentek Power Generac Parts
A list of my favorite Generator & Electrical Tools! https://www.amazon.com/shop/gentek_power
78buckshot
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We have maybe six total B&S and Kohler, I do the Cummins and a few others privately.
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nrp3, I would make a habit of checking the valves, the VanGards have the same specs as Generac. As the valve seat sinks in the head the clearance becomes tighter just like the Generac. One nice thing about Kohler is hydraulic lifters - no adjustment needed.
nrp3
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The square tan verticals from Kohler have the mechanical valves though I haven't tried to adjust one of those. .005 on the Vanguard 1/4 past tdc I believe.
ChrisMills
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The air cooled engines can run a bit hot under load for long periods. There's probably no harm in looking at the simple thing first. The different motor oils have different vaporization points. It could be that the oil is vaporizing and being pulled up through the crankcase vent.

I used a 5kw. 10hp.Coleman Powermate converted to dual fuel to provide backup power here at home. One of the problems that i ran into when converting the B&S was that a set of hardened valves was going to be needed to run propane. I contacted the company and B&S didn't make them at the time. The alternative was to use an " ashless" motor oil. You know ... something that wouldn't vaporize and create ash deposits on the valves. That oil turned out to be Red Line full synthetic 5w30 in my case. I did regular oil changes but can't recall ever having to add make up oil. The motor held up for 15 years before it finally gave out. I repowered the gen head and it's still in service.

It's an old thread but i just thought to toss it out there as food for thought. It might help someone down the line.
kb8vul
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Any of the low HP air cooled engines are going to have that valve sink issue.
The valve beats the valve seat up and closes up the valve lash.

As far as oil usage. I am thinking that make of the small engines call for oil changes at 10 hours.
And letting one run to the point of being dry and dropping oil pressure is really hard on them.

What to check on a high oil consumption motor.
First is plugs. And if it's a LP / natural gas unit, they will really tell the tail as neither will carbon up a plug much.
If you are getting carbon, you are burning oil.
Back to the running out of oil.
I saw a Kohler unit that was in a 10 by 10 building that ran out of oil.
It had a pressure sensor on it and it kept running until the heat was so great in the room that all the plastic on everything started to melt.
The phone on the wall, the UPS front plate, the face plates on the Ethernet switches and network hardware. It looked like it had all been in a fire but there was no smoke damage.
What finally stalled the generator was the air cleaner melted into the carburetor and lodged the throttle plate open and the generator shut down due to overspeed.
We put oil back in it and it would just start and over speed and then fault. The generator tech figured out the air cleaner melted.
But it still runs to this day. Same motor.

If you are thinking rings, do a compression test then put a little oil in the cylinder and rerun the compression test.
If you see a big jump in compression it's got bad rings. Oil will not seal up a leaking intake or exhaust valve.
On a side note, this is a good check for 2 stroke motors like on a chain saw. You put in a bit of oil and see if it starts. If it runs and dies then it's got bad rings.
Two Stroke motors are more dependent on compression and vacuum for their operation than a 4 stroke.

See if the manufacture recommends a full synthetic oil for that generator. If so try running that.
The full synthetics have a higher flash off point where they will begin to vaporize (as mentioned elsewhere)
And verify that the unit has plenty of air flow. Air cooled engine needs lots of air to keep cool, and as mentioned, running hot, with petro based oil can cause it to flash off.
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