Inside the Husqvarna 550XP

[belgian]

If its just a valve or solenoid that controls fuel. Most likely its just a duty cycle controlled solenoid, meaning it just gets a series of on off commands, depending on how many on or off's it gets will vary the amount the solenoid is open or closed, so basically is just turning the solenoid on and off very fast. Would be cool to hook up a lab scope to it to see what its exactly doing.

Oh, nice thread BTW.

Indeed.

Looks like the good old days of carb tuning with a tiny screwdriver are over with them autotunes. Is there anything a simple man can adjust to this type of carb ?
Sorry if this has been talked over already before, but I have not been much on AS lately.

 

[heimannm]

Even with the auto tune, you still have to twist the bottle open and pour it into the glass...

Mark

P.S. Nice to know you're still out there Roland.

 

[deye223]

Now Mitch who in their right mind would want me to work on their saw??? :msp_sad:

not me i want the chimp to do he's off his head

 

[hqv]

Me is wating to see 545 opcorn:

 

[Dan_IN_MN]

If its just a valve or solenoid that controls fuel. Most likely its just a duty cycle controlled solenoid, meaning it just gets a series of on off commands, depending on how many on or off's it gets will vary the amount the solenoid is open or closed, so basically is just turning the solenoid on and off very fast. Would be cool to hook up a lab scope to it to see what its exactly doing.

Oh, nice thread BTW.

Sounds like the fuel injectors in an automobile engine.

 

[mweba]

Isn't it cute?

 

[heimannm]

Hey Mitch - I took a few saws out to Ericksen's this morning before it warmed up too much. One day I will bring the 850, SP81, and the 7900 out and we can see how they compare.

Still a lot of other projects setting around so I won't get bored any time soon, and I added AC to the shop so I'll be comfortable while I'm out there.

And just to confirm what the other have been saying, great thread and great work. I won't claim to understand half of what you are talking about, but it is very well done in any case. Seems like even the modern chain saw has more computing power than the Apollo space craft had.

Mark

 

[Tzed250]

Hey Mitch - I took a few saws out to Ericksen's this morning before it warmed up too much. One day I will bring the 850, SP81, and the 7900 out and we can see how they compare.

Still a lot of other projects setting around so I won't get bored any time soon, and I added AC to the shop so I'll be comfortable while I'm out there.

And just to confirm what the other have been saying, great thread and great work. I won't claim to understand half of what you are talking about, but it is very well done in any case. Seems like even the modern chain saw has more computing power than the Apollo space craft had.

Mark

All is good, as long as Mitch doesn't get a Main Bus B undervolt...

 

[mweba]

All is good, as long as Mitch doesn't get a Main Bus B undervolt...

Aka multiplex. 33 and aging

 

[mweba]

Hey Mitch - I took a few saws out to Ericksen's this morning before it warmed up too much. One day I will bring the 850, SP81, and the 7900 out and we can see how they compare.

Still a lot of other projects setting around so I won't get bored any time soon, and I added AC to the shop so I'll be comfortable while I'm out there.

And just to confirm what the other have been saying, great thread and great work. I won't claim to understand half of what you are talking about, but it is very well done in any case. Seems like even the modern chain saw has more computing power than the Apollo space craft had.

Mark

Heading to town in the morning if your brain is available for picking, I'll stop.


Only thing accomplished today was the piston work. I got destracted by a big block Chevy on Craigslist. Made two stops for fuel on the way home:taped:

 

[Jacob J.]

Indeed.

Looks like the good old days of carb tuning with a tiny screwdriver are over with them autotunes. Is there anything a simple man can adjust to this type of carb ?
Sorry if this has been talked over already before, but I have not been much on AS lately.

No worries Roland. There should be enough old saws around to keep an old dinosaur like yourself in good repair for the rest of your days...

 

[mweba]

Clearance issue to those concerned. Also the cyl skirts need to be cut to clear gasketless

 

[blsnelling]

Clearance issue to those concerned. Also the cyl skirts need to be cut to clear gasketless

Thanks for the tip!

 

[mweba]

Thanks for the tip!

Nother one for you....almost didn't catch it. Marked with a sharpy is a bevel that does not fit inside the case. Must be machined or use a gasket thicker than its height.

 

[ChainFinn]

Wasnt there something with 550 & 560 XP´s....that the "computer" starts to adjust the saw, as well as collect data up, after certain run time and R.P.M´s... somehow i think there was. Bu i am always wrong :msp_biggrin:

 

[Zombiechopper]

Nother one for you....almost didn't catch it. Marked with a sharpy is a bevel that does not fit inside the case. Must be machined or use a gasket thicker than its height.

can you put a chamfer on the case edge?

 

[mweba]

can you put a chamfer on the case edge?

I'm sure you could but I'm not going to split the case to ensure no shavings got past me.

 

[blsnelling]

can you put a chamfer on the case edge?

That's what I was wondering. A chamfer on the case, and one on the bottom of the cylinder.

 

[mweba]

Also for those concerned, in approx two weeks a nice 346xp built by Mr Snelling will be in the classifieds :msp_wink:

 

[Stihlman441]

Nice thread mate,i wish someone would do the same on a MTronic please.