STIHL Hp ultra fail??? Or my fault???

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Bought a brand new 2 stroke mower never been used. (Victa 2 stroke power torque) it says to use 25:1 or 50:1 using there victa formula semi synthetic oil (Valvoline made). I couldn’t find any on shelf so I bought the STIHL go ultra and mixed it at 50:1. I’ve used the mower for 20hr and I thought I’d have a look see on the exhaust port side of the cyclinder. Well I don’t know if it’s already scoring or if it was because I didn’t run it in and it’s just from the initial startup lubing from new. ( I got told I didn’t have to run it in with fully synthetic at 25:1 just to stick to 50:1). It looks like 2-6 scratches on the cyclinder... I was wondering if it’s because not enough or if I should just run STIHL ho ultra at 25:1 or even 32:1.. any input would help cheers I’ll link HD photos below..
 
I wouldn’t worry too much about it. You could run it at 40:1 or 32:1 if you’re really worried about wear. I think 25:1 is overkill.
 
Stihl Ultra is only JASO FB. I'd run a FD rated oil at 32:1 to 25:1 if it were me. Your mower should be okay.
 
I run all my 2-stroke power equipment at 40:1, or slightly richer. I use a 50:50 mixture of Motul 710 and Pennzoil TWC3. Have been doing this for close to 20 years. Most of my piston skirts will show an odd scratch here or there, but the engines run up to 10 years before re-ring.

I just tore down a Red-Max blower to re-ring. It was 20 years old run weekly for at least 2 hours w/o previous internal service. Looked fine with slight carbon cap. Cleaned right up.

Only motor I have lost in the last 30 years was one Homelite 46cc saw engine. A modern one with a CAT in the exhaust. I blame the CAT for too much heat retention. Have never seized a hot saw or a race saw on my mix. Others running much more expensive lubes have...

I have ancient outboards and Weedeaters, inexpensive Ryobi's, and expensive built Husqvarna's. They all get the same mixture. Set the timing right and the mixture, and keep a good air filter on it
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2-strokes never die from too much oil. They will die from too little. But way more important is the mixture control. Slightly rich will live 100 years. Slightly lean will die in an hour ...
 
I don't see the problem in the picture. It's good to run a bit more oil when breaking in a new engine, but I still run my old chainsaw and weed wacker around 25:1.
 
Originally Posted By: Matt2stroke
Bought a brand new 2 stroke mower never been used. (Victa 2 stroke power torque) it says to use 25:1 or 50:1 using there victa formula semi synthetic oil (Valvoline made). I couldn’t find any on shelf so I bought the STIHL go ultra and mixed it at 50:1. I’ve used the mower for 20hr and I thought I’d have a look see on the exhaust port side of the cyclinder. Well I don’t know if it’s already scoring or if it was because I didn’t run it in and it’s just from the initial startup lubing from new. ( I got told I didn’t have to run it in with fully synthetic at 25:1 just to stick to 50:1).

"It looks like 2-6 scratches on the cyclinder..."

I was wondering if it’s because not enough or if I should just run STIHL ho ultra at 25:1 or even 32:1.. any input would help cheers I’ll link HD photos below..




We are looking at the piston are we? I sure hope that's not your cylinder!

50:1 is proper ratio for Stihl Ultra. I use a lot of it. It is a good mix for a chain saw that pulls 14k rpm's, I doubt your mower pulls that kind of rpm, so your exhaust port looks very oil fouled for 20 hours run time. Your picture is shifted 90 degree's? And your exhaust port looks different on the right side which I believe is the floor of the port, just part of the design I guess.

The Scuff could very well be debris sucked in thru the air filter side, but it sure looks like you have enough lubrication in your fuel. Another possibility is not letting the engine warm completely before using, that can cause scuffing on 2 strokes.
 
Light scratches.... definitely NOT scored.

Properly machined modern 2-strokes can all handle 50:1 without any issues.
 
Yeah I asked the guy at STIHL and he said STIHL didn’t pay for the FD rating like they did with the STIHL Hp super because for how many people pay premium for the ultra wasn’t worth it. There super is FD rated. ( not %100 sold on the truth of the matter) but it would make sense ultra would be better than super.
 
New cylinders come with scratches. You even scratch them when you rebuild.
Nothing to worry about.
But richer is better than less oil. My last weed whacker, A Sears Craftsman was 25 years old. It didn't die just got hard to start. My wife bought me a new Echo but I ran 32:1 in it it's whole life and I run 32:1 in the echo too even though it says 50:1. Runs fine.
 
Last edited:
Originally Posted By: Panzerman
New cylinders come with scratches. You even scratch them when you rebuild.
Nothing to worry about.
But richer is better than less oil. My last weed whacker, A Sears Craftsman was 25 years old. It didn't die just got hard to start. My wife bought me a new Echo but I ran 32:1 in it it's whole life and I run 32:1 in the echo too even though it says 50:1. Runs fine.



Yeah I might do what others say and go 40:1,32:1 just to be safe. I know STIHL ultra is good it’s in my STIHL whippersnipper/weed whacker
 
Scoring is bad, but engines can still run fine with them. If your concerned you could do a compression test, if within spec, i wouldn't worry about it. I have a LB duraforce with some scoring from the previous owner and still runs fine, its on the mid level range on compression spec, but its fine. I know a lot of guys running richer mixes in new engines for break in, like 40:1 where it calls for 50:1. I really have seen no difference personally. Measuring the right oil and using fresh gas is key.
 
I ran Sthil HP moto mix fuel for four years, its 50:1. I do get oil coming out of the exhaust. This season I’m giving Amsoil Saber a try at 80:1 or 100:1.
 
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