Is Stihl Ultra HP Oil no good?

Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
...Diagnostic shows fuel was running in the green during last use...

Interesting. Can you elaborate on what that means? Does the motor have some kind of computer that logs everything?

Does "running in the green" mean that the log shows that neither rpms nor temperature were too high?
 
Interesting. Can you elaborate on what that means? Does the motor have some kind of computer that logs everything?

Does "running in the green" mean that the log shows that neither rpms nor temperature were too high?

Yes, it logs the fuel usage during the last use. So, if it was on the low side it might indicate a stopped up air filter so the saw was compensating for the reduced air. If it was on the high side it might indicate the saw compensating for an air leak.
You can learn a lot more if the saw will still run. But, if it won't crank there is not much else it will tell you.
If it is in the green it would not indicate a running issue.
 
The odds of a cold seize with an air cooled motor are extremely low.
Not with a chainsaw. It can happen when someone fires up a chainsaw and goes straight into full throttle cutting. The exhaust side of the piston can expand quicker than the cylinder and rest of the piston causing it to score at the exhaust port.

L8R,
Matt
 
Not with a chainsaw. It can happen when someone fires up a chainsaw and goes straight into full throttle cutting. The exhaust side of the piston can expand quicker than the cylinder and rest of the piston causing it to score at the exhaust port.

L8R,
Matt
Again, the odds of a air cooled motor cold seizing are extremely low.
Guys call things cold seizures all the time, but that doesn't make it so.
In decades of using chainsaws I've never warmed one up and I never cut at partial throttle.
 
I like to warm my saws up. I’ve got a couple that run and sound a bit off, until they’ve warmed up and made a few small cuts. Echo saws, in general, seem cold natured. My Stihl BG86 that I’ve had forever, is very cold natured, so I’m inclined to give them a little time.
 
I'm sure this has topic been hashed to death, but when I did a search, the newest thread I found was over 10 years old, so ... here we go again.

It seems like I've read here where people have said that the Stihl Ultra HP oil is crap. Am I remembering that right?

The reason I ask is, I recently bought a Stihl FS91R string trimmer, which comes with a 2-year warranty, and the dealer said they'd double the warranty to 4 years if I bought a 6-pack of Stihl Ultra HP oil bottles (enough in each to mix one gallon at 50-to-1).

I've been using Mobil 1 2T Racing Synthetic oil in all my 2-stroke equipment now at 40-to-1 for years with nothing but good results. I'm tempted to stick with that plan, but if this weedeater is gonna go belly-up, I figure I'd better at least have the Stihl Ultra HP oil in the 2Mix if I take it back to the dealer under warranty...

Kind of a weird deal on this one, because it's technically a 4-stroke motor but you run 2Mix fuel in it...I was very skeptical that it would have decent power, but everybody said the machine was real torquey, and sure enough, it is ... I'll be dammed if I understand why, though...I would have expected a 2T motor of equivalent size to have way more power...

Anyway sorry, I'm rambling...long story short, I'm real pleased with this weedeater, seems to be more powerful than any I've owned, and I've owned several over the years...
My dealer service tech said the Stihl Ultra is designed specifically for the 4-mix engines, and it works very well for them. So I use it with my string trimmer, and all the saws get Echo Red Armor.
 
Sometimes you just don't know. We have a MS500I in the shop that is scored just on one side of the piston looking through the exhaust port, Only 1/4 inch maybe. Looks like a little gouge out of it. Professional outfit uses the same mix in everything. Diagnostic shows fuel was running in the green during last use.

Saw is about a year old, but commercial use warranty is only three months.

Those saws aren't 100% duty cycle. You can dog them until they get too hot.
But, it is really just speculation.
I have a 500i that seized on the exhaust port side , using 45 to 1 fuel and have been for years in all my stihl saws ( MS660 MS088 MS036 ) with no problems the 500i is about 2 years old and has turned into my goto saw for its power to weight ratio. Was using with a 24 inch bar and it just stopped, no signs of a impending seize , thought it was fuel but still had 1/2 a tank , went to pull over and it was solid. I am replacing the barrel and piston but would love to know WHY it seized. If anyone has seen this happen before and worked out why I would love to know, Thanks...Allan.
 
I have a 500i that seized on the exhaust port side , using 45 to 1 fuel and have been for years in all my stihl saws ( MS660 MS088 MS036 ) with no problems the 500i is about 2 years old and has turned into my goto saw for its power to weight ratio. Was using with a 24 inch bar and it just stopped, no signs of a impending seize , thought it was fuel but still had 1/2 a tank , went to pull over and it was solid. I am replacing the barrel and piston but would love to know WHY it seized. If anyone has seen this happen before and worked out why I would love to know, Thanks...Allan.
It likely needs the software reset
 
Meh. I have one I use and another nib. They aren’t for everyone for 1 reason or another.

But you not justifying owning one doesn’t change the likelihood of his needing a reset. So 🤷🏽‍♂️

Whatever. After a few $1400 saws that puke and you can't put your finger on it you get a bad taste in your mouth.

You can run a 390XP or MS660 like forever.
 
Whatever. After a few $1400 saws that puke and you can't put your finger on it you get a bad taste in your mouth.

You can run a 390XP or MS660 like forever.
You have a built in bias from working in a repair shop - you don't even see the saws that keep on trucking without issue.
 
You have a built in bias from working in a repair shop - you don't even see the saws that keep on trucking without issue.
That's possible. 90% of what we do is weed eaters, blowers, and home owner saws. A few concrete saws.
We have two MS500I's. One had a tree dropped on it, the other is scored for an unknown reason. An MS462CM with the oil pump screwed by running it with no drum bearing. That's all the "big" saws this week.

I guess what makes it frustrating with the MS500I is you never know the reason for the scoring.
Most other stuff you will chase it down eventually.

Had one MS500I that scored the first day, just slightly. Pro user. I cleaned the cylinder and they sold it to somebody else who has been using it no issues. So, what the hell.
 
Doesn't the 500i have a really questionable air seal at the filter? That's why I avoided it and went with a 7310p, kinda ridiculous to have to upgrade an air filter connection a $1600 dollar saw. Just saying, that could be letting things in and contributing to the scoring.
 
Doesn't the 500i have a really questionable air seal at the filter? That's why I avoided it and went with a 7310p, kinda ridiculous to have to upgrade an air filter connection a $1600 dollar saw. Just saying, that could be letting things in and contributing to the scoring.
Lots of Stihls have questionable air filtration. They still don’t seem affected by it or really require modification. But Husqy and Echo have their models with sucky filters too. I love the 590/620’s and they have a good rep for durability, but with crappy filters. Husqy’s air injection works well though, too keep the air boxes really clean. Echo’s auto style filters are the best for keeping the intake clean but the older models get really dirty inside the air box. I can run a Husqy all day and hardly need to clean the inside of it.
 
There are guys on here (gals too) that have probably forgot more about 2 stroke saws than I will ever know. With that said I think the few problems with the 500I as well as other makes are a result of the good ole gov regs coupled with outsourced parts. They have leaned them out so much and tried to lighten the powerheads to the point I am surprised they dont grenade more often. Thats speaks volumes to the metallurgy of the modern saws.
 
Not convinced that a few milligrams of wood dust ingested per gallon of 2Mix is gonna score aluminum.
Don't they use aluminum oxide to sand wood?
 

Latest posts

Back
Top