Two 310's have blown in a month

[bluto]

I have a customer who has destroyed 2 310's. The piston and cyl. are scored on the ex. side on both saws. I know this guy, and how he takes care of his equipment, and it most likley isnt him. Same gas has been used in 2 other saws...90+ octane, minimal alcohol. Pressure and vac. tested, tight as a drum. No obstructions in the muffler and fuel line, filter and carb is in good shape. One of the 310's was 15 months old and the other is about a month. He has been running Stihl oil, and when I checked there was nothing but premix in the fuel tanks. I'm scratching my head, any thoughts would be appreciated.
Jim

 

[Saw Dr.]

Were the limiter caps removed, and saws tuned in properly?

 

[andrethegiant70]

EPA blues. These are good saws that Stihl has had to gradually strangle for EPA purposes. They are at the end of their run and are being replaced. To have a reasonable life span, the caps should be pulled, the mixture richened, and the muffler drilled out a bit. Until one gets the time to do this, these saws should be given healthy cool-down times and the chains should be kept very sharp.

 

[roncoinc]

Paint em RED and call them Dolmar's,already made in germany..

LOL,JK,had to say that

bummer news man,,sometimes hard to tell when something like that happens.

warranty on newer one anyway ??

 

[woodguy105]

Fish will be making his assessment soon I'm sure...

opcorn:

 

[Fish]

Sure.....

Likely customer fault, but how in he ll could we determine that with no
, absolutely no information or pics......

We need pics of the "bended" fuel lines, both sides of the piston, etc....

We could call for a major recall from Stihl, but........................

 

[howellhandmade]

Have 310s been toasted by any other customers?

Jack

 

[PogoInTheWoods]

Have 310s been toasted by any other customers?

Probably just by clueless customers who shouldn't own saws, or who just happen to buy two indentically faulty saws 15 months apart. (ahem....)

Sheesh.

The 310 is a vastly under rated saw with lotsa guts and grind in the hands of
a capable operator -- especially when mildly modded. It's also a very forgiving saw in the hands of a moron.

I've beat mine senseless over the years and it still makes me look like the one with no sense when I question its capabilities. ( Yeah, I'd be the moron in this scenario.)

A buddy o' mine just took down 40 major old growth trees with his slightly
modded 310 and is ready for more. It screams and pulls a 24" chain like it was made for it outta the box.

Anyone who blows up a 310 probably shouldn't be running one to begin with. Anyone who blows up TWO in a month is an idiot.

Poge

 

[bluto]

I will get some pictures on Monday.

 

[Justsaws]

There are two saws.
One is a month+/-.
One is a 18months old+/-.

They were not purchased at the same time?
Both are owned and operated by the same person?
Both passed all of the tests you do for warranty work?

Take the carbs off the saws and put them on a known proper running saw.

Without any more information it sounds like operator error.

 

[ckelp]

+1 maybe the guy straight gased them and is trying to cover it up

 

[stihlboy]

I have a customer who has destroyed 2 310's. The piston and cyl. are scored on the ex. side on both saws. I know this guy, and how he takes care of his equipment, and it most likley isnt him. Same gas has been used in 2 other saws...90+ octane, minimal alcohol. Pressure and vac. tested, tight as a drum. No obstructions in the muffler and fuel line, filter and carb is in good shape. One of the 310's was 15 months old and the other is about a month. He has been running Stihl oil, and when I checked there was nothing but premix in the fuel tanks. I'm scratching my head, any thoughts would be appreciated.
Jim

he have a son?

neighbor use the saw?

he run it at half throttle between high and low where the carb goes lean?

he run it out of gas to store it?


get him another 310, cut the limiters, mod the muffler, and send him on his way with synthetic oil

 

[Fog1965]

Sounds like E10 gasoline. I have a 290 that had been running OK, not great but OK since 2003. E10 was pushed in our area earlier this year and there were a number of saws, including mine, that have the same problems as the ones you described. The condition of my saw was the same as you described - no problems except for the scoured cylinder.

Now, mine is running great after a new engine thanks to Fish. Tabs are gone off the caps and it runs like it should, idles at 2,000 and 13,500 WOT (4 cycling and the ring not seated). I did not have to change anything else on the engine except for the muffler. Opening up the muffler makes a big difference in the amount of cylinder heat - which is worse when you go to E10 gas. I did change the brand of oil and amount I use after taking the engine apart and seeing how it is made, but that is another story - not getting into one of those "oil war" threads...

A combination of the E10, with the "factory" settings and EPA muffler will fry a 290/310/390 that was already set on borderline lean (on a cool day) - which is what the EPA mandated factory settings are (14.7:1 is "factory" fuel/air ratio and E10 changes those settings to 15.2:1-15.3:1 with the extra oxygen in the alcohol).

Fog

 

[howellhandmade]

+1 maybe the guy straight gased them and is trying to cover it up

I'd think with straight gas the intake side would be scored, too. Just sounds lean.

Jack

 

[PogoInTheWoods]

Sounds like E10 gasoline.
A combination of the E10, with the "factory" settings and EPA muffler will fry a 290/310/390 that was already set on borderline lean (on a cool day) - which is what the EPA mandated factory settings are (14.7:1 is "factory" fuel/air ratio and E10 changes those settings to 15.2:1-15.3:1 with the extra oxygen in the alcohol).

Fog

I'm very interested in the source(s) of your data with particular respect to the Stihl series in question relative to the ambient temperature affect on borderline lean settings per mandatory EPA factory settings.

Poge

 

[Fog1965]

Pogo,
The fuel/air ratio numbers came from the EPA website under reformulated gasoline. These are the numbers that Stihl, Husky and all the other manufacturers have to shoot for - and the reason for the limiting tabs.

Fuel air ratios have always been at a specific temp and altitude - 70 degrees and sea level. You can find that in any decent engine tuning book or book on making horsepower. One of mine is "the Two Stroke Tuners Handbook". There are also a number of books on drag racing engines that have information about air density, temp, and altitude. Those are idealistic conditions where you make horse power, also why gas mileage is better at night in Texas. When the air gets "warm" the settings change and so does the needle settings. If it is set where it should be, a change in air will not really affect a chainsaw enough to go lean. If a chainsaw has the EPA settings, then warm air will definitely affect the engine. Add E10 and you need mine shaft weather.

A high performance two cycle will be affected by any weather changes. At a race I have to adjust the needle on my engine each run through out the day as the weather changes. Those engines are on the ragged edge and we notice any change in weather. There are also those days that the weather sucks and you just can't make as much power. Which is why I would never set a chainsaw with a tach to factory rpms- could be a bad air day and you would fry the engine trying to hit 14,000 when the best it can get is 13,500. We carry a "weather station" and know what the conditions are and if the air is bad, then you just live with it - everybody is running the same air. But, even with the engine dialed on kill every run, we never run them as lean as the numbers the EPA mandates for everyday usage on chainsaws.

Fog

 

[PogoInTheWoods]

Pogo,
The fuel/air ratio numbers came from the EPA website under reformulated gasoline.
Fog

Fog,

Thanks for the detailed followup. It just seemed like the initial assertion was a bit vague and was targeting the MS290, 310, 390 series in particular -- sorta in generalizations for those of us not quite as informed on the EPA stuff.

I still say anyone who blows up two 310's in a month has bigger problems than not understanding how to re-tune for E10!

Thanks again.

Poge

 

[andrethegiant70]

Fog,

Thanks for the detailed followup. It just seemed like the initial assertion was a bit vague and was targeting the MS290, 310, 390 series in particular -- sorta in generalizations for those of us not quite as informed on the EPA stuff.

I still say anyone who blows up two 310's in a month has bigger problems than not understanding how to re-tune for E10!

Thanks again.

Poge

This is probably true. It does not sound like the paragon of saw knowledge and experience was running these 310s. I sure didn't mean to knock the 290/310/390, I actually think they are very good saws and have held up incredibly well for a homeonwer-type saw.. heck for ANY saw! But I do think the fact remains that, tuned as they are today coming out of the factory, they simply don't run like their older brothers and sisters. If you go run a brand new 290 against an older one I think you will see what I mean. Compare the outlets in the muffler (for instance) and you'll find that they just don't breathe as well. The slightly modded 290/310/390 is a strong running. robust saw. The new ones are anemic in comparison. The good news is that with a little fiddling, you can have a new one that runs like an older one.

 

[Pain Cow]

Ok, I have a year old MS390 that I've done nothing to "mod" wise because I'm happy w/ it. Some of you actually contend that I'm risking damage to my 390 by NOT "modding" it because of the way the EPA knobgobblers have regulated the tunings? Wtf? I never use the ethanol gas.

 

[andrethegiant70]

Ok, I have a year old MS390 that I've done nothing to "mod" wise because I'm happy w/ it. Some of you actually contend that I'm risking damage to my 390 by NOT "modding" it because of the way the EPA knobgobblers have regulated the tunings? Wtf? I never use the ethanol gas.

I'm not sure what your question is. I like that word.. . knobgobblers. That's a hoot!