SuperTech Synthetic Oils

[Japanese]

The OP mentioned ST 5W30 full synthetic high mileage, so I easily found the data sheet for that oil. However both ST 5W30 and 10W30 high mileage are resource conserving oil.
https://pqia.org/supertech-high-mileage-5w30-motor-oil/

There are plenty of 10W30 full synthetic or synthetic blend oils to use, even you can use widely available motorcycle oils that are not resource conserving. For a generator engine I would choose 10W30 over 5W30 because the first one is more stable to shearing.

Just found out that Amsoil has 10W30 Small Engine Oil and it's cheaper than their dedicated motorcycle oil below:
https://amsoilcontent.com/ams/lit/databulletins/g2217.pdf

https://www.amsoil.com/p/amsoil-10w...EkZzAkdDE3NTQ5NzQ2MzckajYwJGwwJGg1NTI4MDA2OTI.

Amsoil 10W30 High Mileage
https://www.amsoil.com/p/amsoil-10w...EkZzAkdDE3NTQ5NzUyMjgkajYwJGwwJGg1MjkzNTM0MDA.

Amsoil Metric 10W30 motorcycle
https://www.amsoil.com/p/amsoil-10w...EkZzAkdDE3NTQ5NzQ1OTEkajYwJGwwJGg5NDUxODgwMDA.

Motul 7100 10W30 4T motorcycle
https://www.motul.com/en-US/products/16501?id=16501&product=MOTUL+7100+10W-30+4T

Motul 5100 10W30 4T Synthetic blend motorcycle
https://www.motul.com/en-US/products/15100?id=15100&product=MOTUL+5100+10W-30+4T

Motul 10W30 Scooter Power 4T MB motorcycle
https://www.motul.com/en-US/products/58010?id=58010&product=SCOOTER+POWER+4T+MB+10W-30

All these are non-resource conserving oils and would be much better choice than 5W30 or 10W30 resource conserving PCMO.
Motul oils are cheaper on Ebay. If any of these are too pricy for you, just use Super Tech 0W40 on your own responsibility.

 

[50yr Street Mech]

A small engine ? Generator, etc. Frequent OCI's are the key the longevity. They don't hold much oil. Common sense.

 

[repairman54]

2x , synth. oil with regard to winter and summer starting / operating temperatures and regular changes and forget about it.
ST has not hurt my fleet of engines at all. Many vehicles over 200k miles also.

 

[steve c]

Nope, not me, different guy.

 

[steve c]

So exactly why would a 0w-40 a3/b4 oil be better for my small engine generator???

 

[repairman54]

So exactly why would a 0w-40 a3/b4 oil be better for my small engine generator???

It covers a wide range of operating temperatures. I would not use a 0 bottom number down south though as they do not see 0f starting temps. Oil viscosity should be matched to the temperature zone unit is being used in. North like NY then 0-40w is fine, down south 15-50w covers that areas temperature ranges.

 

[ATex7239]

Supertech is a good oil. I can't see paying close to a major though Especially since the base stock is mostly
re-refined base oilView attachment 294840

Interesting. Here’s the ST 0W-20 PDS from 2023 for both the 10K and 20K versions. Just goes to show that even sticking with the same oil over time you likely won’t get the exact same oil.