Lakeside53
Stihl Wrenching
Oxygen (in water often) acting on iron causes rust. It doesn't have to be outside.
What's wrong with this picture...
- Thread starter Lakeside53
- Start date
Help Support Arborist Forum:
Oxygen (in water often) acting on iron causes rust. It doesn't have to be outside.
- Joined
- Apr 3, 2002
- Messages
- 6,071
- Reaction score
- 605
The screw that holds the pivot pin for the needle!
RiverRat2
Serio Tree Freak
I cant concentrate Rotten Tree limbs
every time I scroll over anything you post my brain is................. running away with me!!!!!!!
What is not SST cost .10 dang it I cant look anymore!!!!!!
every time I scroll over anything you post my brain is................. running away with me!!!!!!!
What is not SST cost .10 dang it I cant look anymore!!!!!!
Lakeside53
Stihl Wrenching
BINGO
Replace that plated POS with a stainless screw and the problem will be greatly reduced...
- Joined
- Apr 3, 2002
- Messages
- 6,071
- Reaction score
- 605
every time I scroll over anything you post my brain is................. running away with me!!!!!!!
What is not SST cost .10 dang it I cant look anymore!!!!!!
Maybe I should get a free saw for my sig!!!:biggrinbounce2:
damn i lose mine is clean as a whistle had a little sawdust in it though
Stihl_Learning
ArboristSite Member
Great thread Andy
Thank you
Thank you
Just Mow
Don't touch my Willie !!!
every time I scroll over anything you post my brain is................. running away with me!!!!!!!
What is not SST cost .10 dang it I cant look anymore!!!!!!
were you saying something, I keep having boobie flashing through my head.
Lakeside53
Stihl Wrenching
O.K., that's over...
I figure the alcohol in the gas absorbs water. It slowly attacks that screw particularly if it sits in the carb for months. Once the plating is gone, it's rapid rusting.
I see this more and more. Great for service (NOT) but it often clogs the carb really bad. I'm still not sure if I can save that L jet/check valve in that carb, and it's not replacable.
The cylinder cleaned up o.k.. amazing...
I'm replacing all my carb metering arm screws..
I figure the alcohol in the gas absorbs water. It slowly attacks that screw particularly if it sits in the carb for months. Once the plating is gone, it's rapid rusting.
I see this more and more. Great for service (NOT) but it often clogs the carb really bad. I'm still not sure if I can save that L jet/check valve in that carb, and it's not replacable.
The cylinder cleaned up o.k.. amazing...
I'm replacing all my carb metering arm screws..
Just Mow
Don't touch my Willie !!!
I just saw this post and as a follow up, recalling some high school chemistry, if you heat rust in the presence of ally the following happens;
Rust (Fe203) + 2Al (metal) = 2Fe (metal) + Alumina (Al203)
This is a well known chemical reaction called the thermite reaction - you can fuse-join railway lines with it - ie a handfull of rust and Al powder. Any rust get's inside the cyclinder and sits on the piston will convert any nearby ally to a metallic iron coating mixed with a serious abrasive (Al203) - I guess thats what we're looking at.
Rust (Fe203) + 2Al (metal) = 2Fe (metal) + Alumina (Al203)
This is a well known chemical reaction called the thermite reaction - you can fuse-join railway lines with it - ie a handfull of rust and Al powder. Any rust get's inside the cyclinder and sits on the piston will convert any nearby ally to a metallic iron coating mixed with a serious abrasive (Al203) - I guess thats what we're looking at.
Lakeside53
Stihl Wrenching
Great theory, and I remember doing that experiment in School, but the rust never made it to the piston - just blocked the carb and leaned out the mixture.
KMB
Addicted to ArboristSite
Does Stihl have the stainless screws available? Where else is an easy place to get them? And as already mentioned, great thread and info. Thank ya!
Kevin
Jaxx
ArboristSite Lurker
Great post -- informative. Thanks Lake.
Rah's posts were distracting.... If you know what I mean.
Rah's posts were distracting.... If you know what I mean.
Lakeside53
Stihl Wrenching
OK - I agree that the leaning of the mixture was the major culprit but how can you be sure that small amounts of very fine rust didn't get to the piston?
Thanks Lakeside, great post! 
I shuddered when I saw that piston! (I had actually narrowed it down to the screw or the suckback preventer about halfway through the second page. lol)
Could this be one reason they recommend not leaving a saw for extended periods with fuel in it? Maybe better to just run it empty when it will not be used for more than a week or so? Does this happen with saws other than Stihls? I haven't seen this on my Homies or the Mall.
I shuddered when I saw that piston! (I had actually narrowed it down to the screw or the suckback preventer about halfway through the second page. lol)
Could this be one reason they recommend not leaving a saw for extended periods with fuel in it? Maybe better to just run it empty when it will not be used for more than a week or so? Does this happen with saws other than Stihls? I haven't seen this on my Homies or the Mall.
Lakeside53
Stihl Wrenching
It's not a Stihl issue - it's a Walbro/Zama/Tillotson issue... and those carbs are used everywhere. One stupid plated steel part in the carb and the potential for rust exists.
Water in the gas is the real problem. Use fresh mix, no alcohol if possible, dump out your gas cans now and then, don't store it in a saw for more than 60 days etc etc.. If your saw dies and you suspect water in the gas, flush it out and clean out the carb - don't shove it to one side and get back to it months later.
This won't happen in every saw or area, but it sure does happen a lot out here, and more frequenjtly than in the past. The saw in question wasn't even three years old!
Water in the gas is the real problem. Use fresh mix, no alcohol if possible, dump out your gas cans now and then, don't store it in a saw for more than 60 days etc etc.. If your saw dies and you suspect water in the gas, flush it out and clean out the carb - don't shove it to one side and get back to it months later.
This won't happen in every saw or area, but it sure does happen a lot out here, and more frequenjtly than in the past. The saw in question wasn't even three years old!
Lakeside53
Stihl Wrenching
I can't, but I see a a lot of piston failures, and this is was just like all the other abused "lean" burn outs. The user was obviously inept - it doesn't melt down like that in a minute...
