Generator change interval

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Owner's manual for Predator 4000 generator calls for oil changes every 20 hours. Seems a little excessive even by small engine standards, and I run Rotella T5 10W-30 in it. I figured more like 100 hours or annually, and I have an hour meter installed on it. It's barely changed color in the 13 hours on it so far.
 
Oil is cheaper than a good burger- change it . It may seem to be excessive but remember in a small engine it does double duty as a lube & coolant.
 
Based on my experience with generators I would do every 50 hours.
I have a Makita generator that I bought 18 years ago. Used mainly on dirty construction sites. I change it about every 40-80 hours and runs like new. Used 5-30 dino oil in it for years and recently switched to synthetic.
 
Thank you for reminding me. I have the same engine on a snowblower. I ran it for 5hrs and changed the oil. I was expecting shiny bits in the oil. Didn't see any specks at all. Barely used this yr, but it hasn't been changed in 3yrs. Great little engine IMO.
 
I think 1st oil change is after 20 hours. After that, 100 hours is reasonable.
If it's sitting in my garage doing standby use only, I keep it in there for 5 years.
 
The manual definitely calls for 20 hour intervals, and that's what I'd follow. The capacity is only 0.6 quarts, so it's quite a small investment, especially if you're buying 5 quart or gallon jugs.
 
The basic rule of thumb for small engine generators, is that if it does not have an oil filter, you change every 50 hours. If it has an oil filter you can go 100 hours. Some of the more expensive, commercial style generators will want an oil change every 200 hours.

I agree, 20 hours is excessive. To me, that is put in the manual because a lot of people blow up their engines (due to lack of oil), so perhaps that's Harbor Freights way to get out of warranty claims. "Did you change the oil after 20 hours?" No? Sorry, warranty declined.

So if it were mine, I would just go with the standard recommendation above for every other brand. Change it every 50 hours (no filter) or every 100 hours (with filter).

Of course, the standard recommendation to check the oil at every fuel fill up still applies.
 
As a general rule, whatever your manual says is the one to follow.
That is 20 hours of full throttle operation. There is a reason every small engine recommends 20 hrs specially if there is no filter. Keep your air cleaner clean as well.
I am not in longer and longer oil change interval camp.
I have not exceeded 30 hrs in occasions.
 
Originally Posted By: CaspianM
There is a reason every small engine recommends 20 hrs specially if there is no filter.


Which small engines recommend changing the oil every 20 hours?
 
After looking up my manuals, most of them recommend 50 hrs under normal condition and 25 hrs under severe after break-in which requires 5 hr oil change. My Subaru recommended 20 hrs after initial break-in.
Sever condition is defined as hi temp and/or dusty condition. So it is up to the owner to decide.
Perhaps 30 hours would be a more realistic recommendation imo than 20 hrs.
 
Originally Posted By: bubbatime
Which small engines recommend changing the oil every 20 hours?


The manual for the original poster's Predator generator, for one.
 
You guys just made me look at the manual for my Subaru/Robin RG4300iS generator and it states the initial change should be at 20 hrs, but every 100 hrs after that. It does not have a filter.

I did the initial change at 7.5 hrs and found no glitter. Now has 50 hrs and I've changed it twice since then and each time the oil looks almost new coming out.
 
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Originally Posted By: CaspianM
After looking up my manuals, most of them recommend 50 hrs under normal condition and 25 hrs under severe after break-in which requires 5 hr oil change.


This ^

Common practice for countless small engines over the years.
 
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Here in South Florida, I use 15W-50 M1 and change every 50 hours. It's been a winning combination, as I have thousands of hard use hours on my generator. Unlike my neighbors, my generator continues to run perfectly.
 
Why such thick oil needed for a small engine? Unnecessary shear stress which creates more friction & rotational drag. Motor oil has gone a long way.
Today the thinnest oil that works is the one to use.
 
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Thanks all, I changed it initially at 5 hours, didn't see any glittery particles in the oil. I figure I'll go with 50 hours. Yes, HF says you must change it every 20 to satisfy their (short) warranty, but I'm sure it will be fine with HDEO.
 
Originally Posted By: CaspianM
Why such thick oil needed for a small engine? Unnecessary shear stress which creates more friction & rotational drag. Motor oil has gone a long way.
Today the thinnest oil that works is the one to use.


The reason is that these small engines are air cooled, and even then - cooling is minimal. They run hot and especially in hot weather down south, a standard 30-wt will not cut it. Many Katrina survivors that had generators can testify to this, as many of those that ran thinner oils on a continuous-operation basis experienced engine failures. Not all, but many. Summer temps and air-cooled engines can benefit from a 40-wt (or greater), but a robust 30-wt would probably work as well.

For the price, level of protection, and piece of mind, it's hard to beat a good ole HDEO 15w40 (Rotella, Delo, ST, Delvac) in summer temps. In the winter, a standard 30-wt would suffice.
 
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There is no benefit to thicker oil than what is specified by the manufacturer. Read my post again.
Katerina situation and continuous operation is totally a different topic.
 
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