031 and 044bb slowing in the cut?

[taxidermist]

I have a 031 that has fresh rebuilt carb, 150# compression,clean spark arrester and a 18" bar with a 3/8 chain. I have the carb tuned pretty good with a mild 4 stroking.(i have tuned it both ways rich and a tad lean and still does it) It will cut great for a few min of hard cutting then the chain starts to slow in the cut. I can remove it from the cut hit the throttle and it revs right up to a nice fourstroke. Plug looks dry but dark I removed the clutch and cleaned the drum and clutch. It is the all steel clutch,it had some black marks on the clutch but i dont think it was the fiber shoe but i really dont know. I have run the saw on both its sides and also used carb cleaner to check for bad seals but they seem ok with that test.



My 044 is a big bore and muffler mod and it does the same thing. Could this just be the clutches are toast? I dont see any discoloring on either saws.

Thank you,
Rob

 

[taxidermist]

any one want to take a stab at this?

Rob

 

[Adirondackstihl]

Have you ever dressed your bars or cleaned the grooves?

 

[taxidermist]

Have you ever dressed your bars or cleaned the grooves?

031 has a new bar and chain, 044 gets cleaned and flipped every time I change the chain.

Both are oiling very good.

It just seems heat related they both run like a new saw with plenty of power for a while then they slow in the cut. You pull them out wind them up and away they go for a few min.

Stumped!!!
Rob

 

[Aaron441]

Do the engines slow down or just the chains?

 

[taxidermist]

Do the engines slow down or just the chains?

well the engine slows down some but the chain will stop. Its almost like when you engage a saw with a brake, you can hear that the motor wants to power thru the brake.

Rob

 

[Rustynutz]

unusual to have same fault on two saws, hmmm

check for heat in bar, tip and clutch?
well sharpened chain?
chain set to tight?
tuning up when hot?
tank breather?

could be all or non of the above!!!

best of luck with that one!

 

[Rokon]

unusual to have same fault on two saws, hmmm

check for heat in bar, tip and clutch?
well sharpened chain?
chain set to tight?
tuning up when hot?
tank breather?

could be all or non of the above!!!

best of luck with that one!

I'm going with this one.

 

[Busmech]

The only common things between these saw is the name on them, the tension on the chains and the fuel you are using, since they are both losing power I would mix a new batch of fuel and try again.

 

[taxidermist]

O44 is mine and 031 is a friends Different fuel from different cans.

I work on alot of saws so the tuning part I feel i am doing fine with.

Chain tension is fine neither bars show any heat.

Both tanks are venting right.

Rob

 

[Fish]

Show us a pic of both sprockets/teeth.

 

[taxidermist]

Here ya go fish
I know nothing about sprockets as I have never seen a new one. Both are 7 pin 3\8

Rob

 

[Fish]

That is likely the problem on the 031, show a close up pic or two of the bottom end of the chains as well as a close up of the teeth.

Are you interchanging the bars/chains betwwen saws.

The sprocket on the 031 has likely ruined the chain/chains that it is trying to push, looking at the bottom of the drive links will confirm that.

 

[taxidermist]

That is likely the problem on the 031, show a close up pic or two of the bottom end of the chains as well as a close up of the teeth.

Are you interchanging the bars/chains betwwen saws.

The sprocket on the 031 has likely ruined the chain/chains that it is trying to push, looking at the bottom of the drive links will confirm that.

The 031 bar and chain is new with only a few cuts and i dont have any of the old ones here.

I do not swap any parts as the 031 is not mine.

After thinking about you asking about the sprocket i did some reading and will add that the 031 and 41 both have clutch bell ringing while at idle. Is this a clue as to whats going on?

Rob

 

[taxidermist]

First pic is 031 chain only ran a few times 2nd is the 044 with good run time

Fish, were you thinking the 044 sprocket was ok?

 

[Fish]

The 031 bar and chain is new with only a few cuts and i dont have any of the old ones here.

I do not swap any parts as the 031 is not mine.

After thinking about you asking about the sprocket i did some reading and will add that the 031 and 41 both have clutch bell ringing while at idle. Is this a clue as to whats going on?

Rob

Put a new sprocket on the 031, you'll notice a big difference there. The more you run that chain on that sprocket, the more damage you will
do. The bottom of the drive links are already damaged, the bottoms burr and flatten out, binding more and more in the bar groove, and get
real tight as the bar/chain gets hotter/ the heat goes up exponentially as the more friction from the new damage gets even hotter.

 

[taxidermist]

Put a new sprocket on the 031, you'll notice a big difference there. The more you run that chain on that sprocket, the more damage you will
do. The bottom of the drive links are already damaged, the bottoms burr and flatten out, binding more and more in the bar groove, and get
real tight as the bar/chain gets hotter/ the heat goes up exponentially as the more friction from the new damage gets even hotter.

Thank you Fish for the info, I just ordered new sprockets for both after looking at new ones I now see the wear. I will start there.

Rob

 

[taxidermist]

Update... I bought a new sprocket for the 031av and also deglazed the clutch shoes with a little sandpaper and it cuts like a new saw!!!

As for the 044... i took it apart to learn about porting so i will not know until i finish but the sprocket does look whooped!

Thank you Fish for the info.

Rob