572XP not revving up

[jaredk]

Here’s the video of what the saws are doing. It started after I took the oil pump off to look for worn parts due to a small leak. The clutch was on a little tight so I had to throw some starter cord in the cylinder to keep it from spinning and ended up breaking the clutch and getting it off. I replaced the clutch and put everything back together. It will start just fine and high and low idle but with heavy smoke; almost like it's not getting enough air. It won't rev up and even weirder it won't shut down with the choke switch. I removed the choke switch and it had continuity. I checked the air gap for the ignition module and checked it in spec. I removed the carburetor, cleaned the best I could (ultrasonic cleaner) and scoped the bore to check for gouges or damage. Everything checks out… I can only assume it is an auto-tune problem or carb? The air filter is brand new and does the same thing with or without the filter.

I'm thinking of just throwing a new carburetor on it to see if that's all it is but they're kind of pricey. The only other thing I can think of is to pull the jug and see if there is something in the lower intake ports that fell in and is clogging the port... I blew them both out though and seemed like they were ok... I am at a loss here. This is the first time I've had a single issue with this saw

Also.. the 372 and 572 clutches are interchangeable, right? They appear identical

 

[hotshot]

Here’s the video of what the saws are doing. It started after I took the oil pump off to look for worn parts due to a small leak. The clutch was on a little tight so I had to throw some starter cord in the cylinder to keep it from spinning and ended up breaking the clutch and getting it off. I replaced the clutch and put everything back together. It will start just fine and high and low idle but with heavy smoke; almost like it's not getting enough air. It won't rev up and even weirder it won't shut down with the choke switch. I removed the choke switch and it had continuity. I checked the air gap for the ignition module and checked it in spec. I removed the carburetor, cleaned the best I could (ultrasonic cleaner) and scoped the bore to check for gouges or damage. Everything checks out… I can only assume it is an auto-tune problem or carb? The air filter is brand new and does the same thing with or without the filter.

I'm thinking of just throwing a new carburetor on it to see if that's all it is but they're kind of pricey. The only other thing I can think of is to pull the jug and see if there is something in the lower intake ports that fell in and is clogging the port... I blew them both out though and seemed like they were ok... I am at a loss here. This is the first time I've had a single issue with this saw

Also.. the 372 and 572 clutches are interchangeable, right? They appear identical

May want to check the flywheel key to see if it’s partially sheared.

Did you use an impact gun to remove the clutch? It’s bad juju if you used a cord to stop the piston AND used an impact.

 

[jaredk]

That's a great thought

I pulled the flywheel, and it all appears fine—no shearing or damage. I had always just put a screwdriver in the clutch slot and struck it sharply with a hammer to remove it. I will see about ordering the correct one.

I am still at a loss on how to repair it.

 

[WoodmanSr]

That's a great thought

I pulled the flywheel, and it all appears fine—no shearing or damage. I had always just put a screwdriver in the clutch slot and struck it sharply with a hammer to remove it. I will see about ordering the correct one.

I am still at a loss on how to repair it.

It does but doesn't sound like Ignition Timing. My only experience is module failed Ignition Advance.
As just falls on it's face. I'm guessing is not Ignition (maybe?). Again my experience, Homelite SXL, is speed would raise say 1000 rpm then peak out rich being Ignition Advance failure.

Sorry can't help more. Know nothing about Auto-tune.

 

[huskihl]

It’s likely a bad coil. On one I had, the red/blue wires had shorted out from a bare spot. Fixed the bare spot and this is how it ran. New coil and was good to go

 

[Tobystihl]

Sounds like a choke issue!