Losing power in the cut

[Buzz 880]

I have a stihl460 it's only about a year old now but the last few days it has being running like sh.t.The one guy i work with say's it's just to hot out for the saw but we work in hotter weather and my other saws don't act up.It only seems to lose power when the saw in on it's side and under pressure if you let up on it a bit it will clear out and rev back up.Does any one have any idea what would be causing it to lose power?

 

[sILlogger]

not saying what it is, but i had a weird experience like this once with my 046 and it was the impulse hose, it had came loose...put it back on and it ran as it was supposed to

 

[ShoerFast]

.Does any one have any idea what would be causing it to lose power?

Heat dose seem to bring out the worst of things sometime, sort of like how things will wait till the coldest day to brake.

A from the hip .02 cents worth, your saw may be working it's way throu a slight vapor-lock or a slight boiling of the fuel?

Getting problims to duplacate is sort of a start to TS-ing.

Mentioning it before, a problim or not, working in heat is a good time to run the "H" as fat as you can

 

[Buzz 880]

Heat dose seem to bring out the worst of things sometime, sort of like how things will wait till the coldest day to brake.

A from the hip .02 cents worth, your saw may be working it's way throu a slight vapor-lock or a slight boiling of the fuel?

Getting problims to duplacate is sort of a start to TS-ing.

Mentioning it before, a problim or not, working in heat is a good time to run the "H" as fat as you can

I have noticed when re fueling that there is bubbling in the fuel tank

 

[ShoerFast]

I have noticed when re fueling that there is bubbling in the fuel tank

Thats what I'm talking about, for a think, what if it is bubbling in the carby?

Tempory lean, loss of power in a cut.

There is a simple test to do on this stuff they call gas we buy. RVP or the point fuel boils at is just what you would see on a gauge if you capped a sample and put it in a cup of coffee,,, or at 150 Deg. Summer fuel should be a low pressure, like 7PSI, and winter it should be more like 15PSI or so, I think that stuff that we see bubbling away in the tank is closer to 10-12, and there selling it as a summer-blend.

The best summer blend I have found in the Denver area is TA , truck-stop gas.

 

[West Texas]

When it runs differently on a side than it does upright, I suspect a seal. Having said that, I worked on one for a friend off and on for almost a year until I finally replaced the carb and its been running like a jewel ever since. That was after I had cleaned the old carb several times and put in at least two 'kits' before I junked it. There comes a point in time when time is a factor.

 

[Lakeside53]

I'm with westtexas. Seal or carb.. But only a year old? unusual for either. Do a full pressure and vac test to eliminate (or not) the seal.

 

[Buzz 880]

Thats what I'm talking about, for a think, what if it is bubbling in the carby?

Tempory lean, loss of power in a cut.

There is a simple test to do on this stuff they call gas we buy. RVP or the point fuel boils at is just what you would see on a gauge if you capped a sample and put it in a cup of coffee,,, or at 150 Deg. Summer fuel should be a low pressure, like 7PSI, and winter it should be more like 15PSI or so, I think that stuff that we see bubbling away in the tank is closer to 10-12, and there selling it as a summer-blend.

The best summer blend I have found in the Denver area is TA , truck-stop gas.

I would like to try the fuel for Denver but thats a long way to go from Ontario Canada

 

[Buzz 880]

I'm with westtexas. Seal or carb.. But only a year old? unusual for either. Do a full pressure and vac test to eliminate (or not) the seal.

Only a year old and very little time on it as i cut with my 660 most of the time.On cooler day's i don't have this problem just when it is 30 c or hotter

 

[Lakeside53]

Weird...

 

[stihl 440]

460

I had the same problem with my 440 2 yrs. ago.......replaced the fuel filter and it quit. :rockn:

 

[Buzz 880]

460

Cut all day 60 plus tree's temp was 20 c all day never had any problems with the saw could it just be the heat if the saw is anything like me i don't really like the 30 c weather either.

 

[peter399]

Maybe you have forgotten to clean the air filter every 30 minutes ?

..sorry guys, just had to say it

 

[Buzz 880]

Maybe you have forgotten to clean the air filter every 30 minutes ?

..sorry guys, just had to say it

Cutting for a couple skidders dosen't leave much time to clean the air filter every 30 minutes once a day is good bang it out and start cutting again clean it good on the weekend

 

[Lakeside53]

Pete's never seen a Stihl with an HD filter - once a week, maybe... and then only the pre-filter. But, like you said, I like to flap my prefilter on a log once a day.