High temps effect on starting chainsaw??

[john k]

One thing I've learned with my 550XP is never to push the decompression button on a hot day once the saw has already been used - or it will never restart!

 

 

+1

 

I was using a "problem" 550 last week and found that using the decomp on warm starts was a bad idea.

 

However putting it on half throttle (flip choke on then off) and not using the decomp meant it started easily every time.

[SawTroll]

Vapor lock may have something to do with it - and is more likely if the fuel contains ethanol.

 

Use the "fast idle" for warm starting, if you aren't already.

Edited July 1, 2015 by SawTroll

[GardenKit]

The " vapor pressure" of petrol is adjusted at the production facilities to suit the market climate (average).

For instance in the UK we have loosely 'winter grade' and 'summer grade' petrol.

The winter fuel vaporises more easily, but if it was used on the first hot spring day then it would vaporise too easily, causing vapor lock in the fuel pipes.

 

In the same way, fuel blended for the average summer temp in the UK will vapori lock in heat wave temperatures.

 

I guess the Australian fuel will be blended to suit their average seasonal temps too,

[NFG]

Hi

 

Temps here are a fair bit hotter than UK, we measured 41 degrees the other day although the norm is about 27-33 for this time of year.

 

So my Husqvarnas start 2nd or 3rd pull when cold & first pull warm, I find leaving decomp valve in helps when warm.

 

My Stihl is as always tricky to start, as the small carb is susceptible to flooding

 

I avoid leaving them in direct sun

 

N

[mendiplogs]

My 550xp was a pig to start yesterday. Put it down to being left in the sun for a while whilst I was up in the tree. Not sure why it would affect it. It's usually a good starter, hot or cold. Another problem I had yesterday was the tickover after using it. A few times, after trimming fallen bits, the saw wouldn't return to idle and revved a lot higher than it should. A few blips generally cleared it. Wondered if some crap had got into the trigger mech somehow.

 

Hi BOB I had my 660 in the years ago they do not like I've talk to chaps on in the past try put them under tree out of the sun mate thanks Jon

[Stubby]

Hi

 

 

So my Husqvarnas start 2nd or 3rd pull when cold & first pull warm, I find leaving decomp valve in helps when warm

 

N

 

So , just to be clear when you say " leaving the decomp in " you are using it ? ( as in is venting and out is sealing )

[NFG]

So , just to be clear when you say " leaving the decomp in " you are using it ? ( as in is venting and out is sealing )

 

Sorry for ambiguity

 

First time start on my Husqvarna completely cold I use the decomp valve

 

Once warm it generally starts first time without using the decomp valve

 

This seems to work well what ever the temperature, hottest I have worked in is about 32-33 ish

 

I have heard it can damage the start pawls of a 550 by not using the decomp valve but I have a 365 & 346

 

 

N

Edited July 2, 2015 by NFG

[nepia]

The " vapor pressure" of petrol is adjusted at the production facilities to suit the market climate (average).

For instance in the UK we have loosely 'winter grade' and 'summer grade' petrol.

The winter fuel vaporises more easily, but if it was used on the first hot spring day then it would vaporise too easily, causing vapor lock in the fuel pipes.

 

In the same way, fuel blended for the average summer temp in the UK will vapori lock in heat wave temperatures.

 

I guess the Australian fuel will be blended to suit their average seasonal temps too,

 

 

Thanks Barrie; looks like that's probably the answer to my question.

 

Do I take it also that you consider Aspen (shameless plug) less susceptible to temperature extremes?

[alowen]

My Makita wouldn't start today or yesterday, flooded continually. Bought a new spark plug and seems no change. Is it the weather?

[Eddy_t]

Yesterday all our machines had to have full throttle starts, chipper overheated 5 times, in the end the saws wouldn't restart, and no shade to put them in!