Congratulations on your determination and sheer stubbornness to fix it. I totally agree with you that not changing the carb and making the repairs. Not only have you learnt more and shared that with another excellent video,the sense of satisfaction is justified. We all get pissed when something like this happens, but,now you have a great and underappreciated saw added to your arsenal. Top as ever Boedy 👍p.s have you ported it?would love see more on that if you have.
Enjoyed the videos on 357 & 359, they are excellent saws but getting harder to get quality parts for. Just did a muffler mod and a base gasket delete on my 359 was happy with the results. Enjoy all your videos and the effort you put into them, thanks.
Great description and breakdown👍🏻 yeah, I tend to be the person to give carbs multiple tries/teardowns before breaking down and buying new. Usually I win but sometimes... Glad you got the 357's carb all sorted out!
My first 359 broke the chain catch / antivibe ear and I gave it away. A dozen years later I bought a used one that still serves well. Can't bring myself to sell it; I love the weight and feel.
Main jet metering lever springs are usually included in carb service rebuild kits along with gaskets and diaphragms. The main needle pivot arm is spring loaded to close that main jet needle valve against fuel pressure below 15 psi. But the metering diaphragm bears against the opposite end of that pivot arm and can overcome the spring tension to force that main jet open at lower fuel pressure. See that vent hole in the housing cover plate over the metering diaphragm is a vent to atmosphere, so the metering diaphragm works just like the bellows of a vacuum motor, or more exactly like the diaphragm in a pressure regulator. So a variable fuel pressure regulator is what that metering diaphragm and spring loaded needle valve are when operating on a saw that is running. The effect of that variable regulation is to keep a pool of fuel at a precise volume and depth in that carburetor bowl no matter what the effect of gravity, unlike a regular float bowl carburetor where the float regulates the volume of fuel in the carburetor bowl. When fuel is drawn from that space in the bowl through the mixture jets by the suction of intake manifold vacuum on a running engine, the slight vacuum on the fuel side of that metering diaphragm pulls it against the end of that pivot arm and opens the needle more for more fuel flow to maintain the fuel volume in that carburetor bowl feeding the mixture jets. Months of exposure to fuel can make the nitrile rubberized canvas stiff and hardened so that it does not operate smoothly to regulate fuel and it may be that the fuel pump diaphragm can still be good and last twice or more as long as the metering diaphragm which can be serviced easily without even removing the carburetor. The metering diaphragm is suspect number one when a saw that was running well and unused for awhile is started up and runs rough or won't idle or has poor throttle response. Goosing the saw repeatedly for a few minutes may loosen up the metering diaphragm or it may have to be replaced to restore normal operation. It is a good thing to try as a fix for the rough running saw that ran fine before.
Good old Chinesium carbs! I have about 50/50 luck with them, usually due do bad drillings or dirt in the passages where needle adjustments make no difference. At least that one has the hole in the Metering Diaphragm cover plate, many don't have that and it will cause acceleration issues.
Congratulations on your determination and sheer stubbornness to fix it. I totally agree with you that not changing the carb and making the repairs. Not only have you learnt more and shared that with another excellent video,the sense of satisfaction is justified.
We all get pissed when something like this happens, but,now you have a great and underappreciated saw added to your arsenal.
Top as ever Boedy 👍p.s have you ported it?would love see more on that if you have.
Enjoyed the videos on 357 & 359, they are excellent saws but getting harder to get quality parts for. Just did a muffler mod and a base gasket delete on my 359 was happy with the results. Enjoy all your videos and the effort you put into them, thanks.
Great description and breakdown👍🏻
yeah, I tend to be the person to give carbs multiple tries/teardowns before breaking down and buying new. Usually I win but sometimes...
Glad you got the 357's carb all sorted out!
My first 359 broke the chain catch / antivibe ear and I gave it away. A dozen years later I bought a used one that still serves well. Can't bring myself to sell it; I love the weight and feel.
Main jet metering lever springs are usually included in carb service rebuild kits
along with gaskets and diaphragms. The main needle pivot arm is spring loaded
to close that main jet needle valve against fuel pressure below 15 psi. But the
metering diaphragm bears against the opposite end of that pivot arm and can
overcome the spring tension to force that main jet open at lower fuel pressure.
See that vent hole in the housing cover plate over the metering diaphragm is
a vent to atmosphere, so the metering diaphragm works just like the bellows
of a vacuum motor, or more exactly like the diaphragm in a pressure regulator.
So a variable fuel pressure regulator is what that metering diaphragm and
spring loaded needle valve are when operating on a saw that is running.
The effect of that variable regulation is to keep a pool of fuel at a precise
volume and depth in that carburetor bowl no matter what the effect of
gravity, unlike a regular float bowl carburetor where the float regulates
the volume of fuel in the carburetor bowl. When fuel is drawn from that
space in the bowl through the mixture jets by the suction of intake
manifold vacuum on a running engine, the slight vacuum on the fuel
side of that metering diaphragm pulls it against the end of that pivot
arm and opens the needle more for more fuel flow to maintain the
fuel volume in that carburetor bowl feeding the mixture jets. Months
of exposure to fuel can make the nitrile rubberized canvas stiff and
hardened so that it does not operate smoothly to regulate fuel and
it may be that the fuel pump diaphragm can still be good and last
twice or more as long as the metering diaphragm which can be
serviced easily without even removing the carburetor. The metering
diaphragm is suspect number one when a saw that was running
well and unused for awhile is started up and runs rough or won't
idle or has poor throttle response. Goosing the saw repeatedly for
a few minutes may loosen up the metering diaphragm or it may
have to be replaced to restore normal operation. It is a good thing
to try as a fix for the rough running saw that ran fine before.
Some nozzles are hard to get nowadays too. So that’ll make em hard to fix.
Thanks for the vids on these saws Boedy, really good stuff brother.
It is called pop off pressure, and you check it with a pressure tester. It should hold pressure around 15 psi and pop off around 20-25 psi.
Buying cases can be tough. I had to do that with my 394. Three sets before I got a good one
Thanks good job
The cheap carb rebuild kits the metering levers they include typically are too sloppy. Some kits are great and some are junk.
Yeah
Compliments from me today 😊
Good old Chinesium carbs! I have about 50/50 luck with them, usually due do bad drillings or dirt in the passages where needle adjustments make no difference. At least that one has the hole in the Metering Diaphragm cover plate, many don't have that and it will cause acceleration issues.
What about swapping the SN # plate over to a 359 case? Just a thought
Yeah, I learned today.
I am 1 day smarter 😊
Do you ever watch Leon's chainsaws? He talks about carbs all the time. Just saying is you ever need any help. Although you explain it much better!
👍👍
👍🆙BigGuy