I have had both concrete saws and vac trucks running right outside the cement bunker that is our office. It's a toss up which is more annoying.
wood dust in the carb hard on the saw?
- Thread starter echomeister
- Start date
Help Support Arborist Forum:
A good lesson in the way of things is taking a Sawzall and cutting a steel pipe at ground level with concrete reinforcement poured in and see what happens to your Sawzall blade instantly when it hits the concrete.
Then you go get the track hoe and dig the sucker up.
Then you go get the track hoe and dig the sucker up.
Hermio
Addicted to ArboristSite
I wrecked an MS441C while changing the spark plus. I did not clean the area around the spark plug carefully enough, and the cylinder was scored, resulting in loss of compression. Sawdust was the culprit, though it may not have been just "fines".
Hate to be argumentative or whatever. But, I doubt that.
I was thinking the same thing.
Hermio
Addicted to ArboristSite
On what basis would you doubt that? My saw was running fine before I changed the spark plug, and then it ran very badly and was very hard to start, developing little power and often stalling when warmed up. I took it in for repair and the dealer opened it up and the scoring lines on the cylinder wall were numerous and deep. The change was dramatic, and all of this happened immediately after the spark plug change. Do you have an alternate explanation?
Correlation isn't causation Mr. Engineering guru.
A little bit of saw dust isn't going to score a piston to the point it loses compression, if at all.
Kind of like the saw coming in with a lean sieze and the tank full of fresh mix. "It just happened."
Exactly.
I thought you wore the 441 out? Now the story changes and it scored.
Hermio
Addicted to ArboristSite
OK, troll. How do you explain an immediate lo9ss of compression and performance?
Hermio
Addicted to ArboristSite
The story has not changed. I always said it failed due to sawdust getting into it. That clearly wore it out.
Hermio
Addicted to ArboristSite
Definitely not a lean seize. I have always used a 50:1 ratio for that saw.
It was an analogy. If you think a dab of saw dust ruined your saw it's OK with me.
Hermio
Addicted to ArboristSite
The dealer thought so, too. The only good thing is that, after they told me repair would be $1100 for a new block, piston and crank, they offered me an MS500i for $1180, which I accepted. What an upgrade! It not only cuts faster, it cuts more per unit of fuel used.
Sounds like you have you answer… he wanted to sell you a new saw…
Did he by chance take your old saw in for some credit or offer to buy it “for parts” or the like?
It’s easy to accidentally tap the end of your plug on the way to reinstalling it and cause the gap to be smashed… which of course could cause the saw to run badly… I can’t tell you how many “blown up” motorcycles I’ve seen after somebody smashed the gap in the spark plug or had the mixture screw rattle out of the carb or some similar minor problem that caused the bike not to start or be able to idle or whatever happened and their desperate dishonest mechanic told them the motor needed a rebuild…
Hermio
Addicted to ArboristSite
The dealer actually tried to sell me an MS462 as a comparable replacement, saying the 500i was too expensive. But the price I paid for the 500i ($1180) was way below market price at the time. No one was advertising it for less than $1400 in 2022; some were advertising over $2000. I wondered at the time if they looked up the wrong price. The dealer as an organization did not offer me anything for the 441C, but one of the mechanics personally offered $150 for parts, which I accepted. Believe me, the 441C was very badly scored. I am sure I did not smash the gap on the spark plug, but even if I had, that would not cause the scoring.
Yeah im not saying you smashed the gap… I’m just saying all kinds of stuff can happen.
And you’re right that’s a damn good price for the 500
I’ll be really interested to see how you like the fuel injection especially after a year or two. I think about motorcycles and chainsaws as basically the same kinds of animals and when they rolled out fuel injection on 2-stroke KTMs I was racing in ~2018 it was *amazing* and even though it took them a few years to work out the bugs and it requires a computer to work on it it’s hard to argue with the results they are getting with them now..
And you’re also right that smashing the gap wouldn’t cause the scoring but frankly there are thousands (if not millions) of chainsaws and 2-stroke motorcycles running out there with scored pistons… because we’re burning oil in the premix it’s really hard to tell you’re burning oil because… well… we’re ALL burning oil all the time 
But sounds like you got a good life out of your old saw and a damn good price on your 500.
With the fuel injected 2-stroke motorcycles KTM has been making for the last 3 years they are absolutely *AMAZING* and sled adjust for altitude changes (no more re-jetting required for sea level vs mountains) and they make so much more power and run so so so well I’m waiting for the day I can buy a fuel injected saw with confidence. Maybe that day is now?
But sounds like you got a good life out of your old saw and a damn good price on your 500.
With the fuel injected 2-stroke motorcycles KTM has been making for the last 3 years they are absolutely *AMAZING* and sled adjust for altitude changes (no more re-jetting required for sea level vs mountains) and they make so much more power and run so so so well I’m waiting for the day I can buy a fuel injected saw with confidence. Maybe that day is now?
Anecdotal evidence, but I think still worth the mention...
At my Echo Dealership, the Service Manager showed me a top end that had, what to me, seemed like an odd colour. I asked about it, and he said.. " It's from wood dust getting past the filter.: There was an odd "burnished" look.. a kind of light brown / tan colouration that I'd not seen before, I asked if that was why the saw was in pieces on the bench, and he said no.. The wood ingested, is burned up during normal combustion, and just resulted in some discolouration. Sawdust isn't capable of scratching metal in small quantities. Remember, the fines would be sucked into the combustion area, and burnt immediately to ash. Fines or ash, even if a very, very small percentage of them got stuck between the piston and the sleeve, would have minimal effect or consequences to the saw. They simply deposit, what is probably basically creosote on the piston dome, and on the top of the combustion chamber. That was the discolouration that let them know that the filter was letting stuff get through. That, and the presence of fines where they shouldn't have been in the induction area of the saw.
Are fines good for a saw? Uhhhh... no!! Do they cause catastrophic failure? I sincerely doubt it.
At my Echo Dealership, the Service Manager showed me a top end that had, what to me, seemed like an odd colour. I asked about it, and he said.. " It's from wood dust getting past the filter.: There was an odd "burnished" look.. a kind of light brown / tan colouration that I'd not seen before, I asked if that was why the saw was in pieces on the bench, and he said no.. The wood ingested, is burned up during normal combustion, and just resulted in some discolouration. Sawdust isn't capable of scratching metal in small quantities. Remember, the fines would be sucked into the combustion area, and burnt immediately to ash. Fines or ash, even if a very, very small percentage of them got stuck between the piston and the sleeve, would have minimal effect or consequences to the saw. They simply deposit, what is probably basically creosote on the piston dome, and on the top of the combustion chamber. That was the discolouration that let them know that the filter was letting stuff get through. That, and the presence of fines where they shouldn't have been in the induction area of the saw.
Are fines good for a saw? Uhhhh... no!! Do they cause catastrophic failure? I sincerely doubt it.
