- Local time
- 7:54 AM
- User ID
- 6487
- Joined
- Jun 21, 2018
- Messages
- 438
- Reaction score
- 1,842
- Location
- Oklahoma
So, to give you guys some background info...
Saw = MS 461, purchased in Nov 2019, Dual port muffler added prior to first start, carb limiters removed prior to first start. Running on 91 Octane E-free with Echo Powerblend at 40:1. Chain sharpened at every or every other tank fill-up. Filter cleaned at each fuel up.
Was running my newest MS461 over the weekend, noodling up some big rounds up. I ran 3 tanks of fuel through the saw with no issues. Filled up the 4th tank of fuel, blew the filter out, ran a file across the cutters, and fired her back up.
Put the bar into another round, made it about 1/2 way into the round, the saw screamed as RPMs gained rapidly. I assumed an air leak but only have about 20 or so tanks through the saw.
Shut her down immediately, stripped her down, moved piston to TDC and started the vacuum test. Pumped my Mity Vac up to 0.5bar (14.76 in/Hg) and moved on to sharpen another saw. Left it for around 15-20 minutes and the needle never moved. Bled it off and pressured the case up - hit 0.5bar (7.25psi) and left the saw for another 10 minutes or so, the pressure held just as the vacuum did. I fingered the intake boot around to see if I could expose a crack or tear while under pressure and vacuum. Nada. Rotated the flywheel by hand while under vacuum and pressure to see if a crank seal was bad at a certain spot. Nada.
So I don't think I'm sucking air, seals are good, gaskets are good, intake boot is good, impulse line is good, fuel line is good (as is filter pickup).
Put her back together and fired her up. Set the carburetor to base settings, H out 1 1/2 turns and L out 1 turn. Fired her up, dialed in the L and LA for solid throttle response, threw her back into the round to tune the H end, but had to back her out another 1/2 turn for a full 2 turns out on H to get her to burble coming out of the cut. And the burble still isn't consistent with no load. The saw runs strong, but when I lift to unload the chain, it will burble some but not every single time. Is 2 full turns out normal? Abnormal?
Whiskey Tango Foxtrot...
The saw is new enough that I would assume the metering diaphragm and gasket are sound. I would also assume the pump diaphragm and gasket are sound. What else in the system could cause my condition? Trash in a carb needle valve?
Saw = MS 461, purchased in Nov 2019, Dual port muffler added prior to first start, carb limiters removed prior to first start. Running on 91 Octane E-free with Echo Powerblend at 40:1. Chain sharpened at every or every other tank fill-up. Filter cleaned at each fuel up.
Was running my newest MS461 over the weekend, noodling up some big rounds up. I ran 3 tanks of fuel through the saw with no issues. Filled up the 4th tank of fuel, blew the filter out, ran a file across the cutters, and fired her back up.
Put the bar into another round, made it about 1/2 way into the round, the saw screamed as RPMs gained rapidly. I assumed an air leak but only have about 20 or so tanks through the saw.
Shut her down immediately, stripped her down, moved piston to TDC and started the vacuum test. Pumped my Mity Vac up to 0.5bar (14.76 in/Hg) and moved on to sharpen another saw. Left it for around 15-20 minutes and the needle never moved. Bled it off and pressured the case up - hit 0.5bar (7.25psi) and left the saw for another 10 minutes or so, the pressure held just as the vacuum did. I fingered the intake boot around to see if I could expose a crack or tear while under pressure and vacuum. Nada. Rotated the flywheel by hand while under vacuum and pressure to see if a crank seal was bad at a certain spot. Nada.
So I don't think I'm sucking air, seals are good, gaskets are good, intake boot is good, impulse line is good, fuel line is good (as is filter pickup).
Put her back together and fired her up. Set the carburetor to base settings, H out 1 1/2 turns and L out 1 turn. Fired her up, dialed in the L and LA for solid throttle response, threw her back into the round to tune the H end, but had to back her out another 1/2 turn for a full 2 turns out on H to get her to burble coming out of the cut. And the burble still isn't consistent with no load. The saw runs strong, but when I lift to unload the chain, it will burble some but not every single time. Is 2 full turns out normal? Abnormal?
Whiskey Tango Foxtrot...
The saw is new enough that I would assume the metering diaphragm and gasket are sound. I would also assume the pump diaphragm and gasket are sound. What else in the system could cause my condition? Trash in a carb needle valve?
