Husqvarna 350 - confirm diagnosis

[mudfly]

Hello,
Relatively new to rebuilding saws. My FIL asked me to take a look at his Husqvarna 350 that wasn’t running correctly. Well it was scored pretty bad so I popped for a meteor piston and cylinder to replace. New aftermarket bearings and seals on the crank. Went back together with motoseal. New impulse line. Fuel line was fine when I checked it out. Upgraded to the metal clamp on the intake.
Pressure and vac tested fine.
it’s running great on its second tank of fuel, but I’m having a hard time getting the carb to stay in tune on the low end. Today it seemed lean on the low end so I was going to give it a 1/8 turn. As I touched the low speed screw, but hadn’t moved it yet, the idle dropped from lean to way rich.
I’m assuming that there is an oring on the jets that needs to be replaced? I haven’t been into the carb yet but seems like that is my obvious next step unless I’m missing something?

Any other thoughts or insights from the experts?

I want to get this running well for him before I return it.

 

[Bob Hedgecutter]

Clean, kit and pressure/vac test the carb alone.
Or replace the carb with a know good 357/359 carb.
If you are 100% the rest of the saw is still air tight.

If the cylinder to clamshell is warped- (not uncommon on these) it could be opening when the saw is warmed up- but sealed when cold.

 

[dave ensign]

A good know carb is a great idea, Is there an Oring on either jet???

 

[mudfly]

Which is the better carb on these the walbro or Zama? I have a 359 I could rob from temporarily but that’s at the other farm 4 hours away.

 

[Bob Hedgecutter]

Which is the better carb on these the walbro or Zama? I have a 359 I could rob from temporarily but that’s at the other farm 4 hours away.

The 357/359 carb is usually reserved for those making members of this family of saws run a bit hotter- so they can drink a bit more.
I would clean and kit your 350 carb first- double check the metering lever height and see what that does first.

 

[oldbuzzard]

You can buy brand new carbs for those saws on eBay for $15. They really aren’t worth rebuilding. You should definitely replace the intake boot with the metal clamp version while you are working on it.

 

[mudfly]

You can buy brand new carbs for those saws on eBay for $15. They really aren’t worth rebuilding. You should definitely replace the intake boot with the metal clamp version while you are working on it.

Thanks. It already got the metal clamp.

 

[stihltech]

You must find a way to pressure and vacuum test the bottom end. You will never make a carburetor work correctly with a vacuum and/or pressure leak.
That being said. Get the new carburetor. You have a 50/50 chance of the $15 carb working. From experience.

 

[mudfly]

You must find a way to pressure and vacuum test the bottom end. You will never make a carburetor work correctly with a vacuum and/or pressure leak.
That being said. Get the new carburetor. You have a 50/50 chance of the $15 carb working. From experience.

I did pressure and vac test the engine assembly. I mentioned that in my first post.

 

[Vintage Engine Repairs]

New carb kit and clean all the drillings. I’d suggest that you don’t buy a Chinese AM carb; oem are more reliable and give you a better metering of fuel.

 

[a. palmer jr.]

I changed my 359 from Walbro to Zama because of the sticking accelerator pump on the Walbro..wasn't sure I could fix the Walbro and didn't want to mess with it anyway..

 

[a. palmer jr.]

New carb kit and clean all the drillings. I’d suggest that you don’t buy a Chinese AM carb; oem are more reliable and give you a better metering of fuel.

I wonder what's the difference between a Chinese AM carb and a Chinese OEM carb...

 

[Bob Hedgecutter]

I wonder what's the difference between a Chinese AM carb and a Chinese OEM carb...

QC

 

[stihltech]

I did pressure and vac test the engine assembly. I mentioned that in my first post.

Sorry missed it

 

[isaaccarlson]

Cheap ebay carbs are garbage. If you are going to buy one, get the real deal.

Actually clean the carb, because most people don't.

I have a ported 350 and have ported several more. The stock carb is great and can provide plenty of fuel. Mine will do 13k in the cut, and has plenty of fuel.

I think it is a dirty carb or an air leak.

 

[Aknutter]

https://www.arboristsite.com/threads/look-what-was-causing-me-lean-symptoms.359348/

 

[isaaccarlson]

Actually clean the carb, because most people don't.

 

[a. palmer jr.]

I don't consider a carb cleaned unless it is soaked in carb cleaner then rinsed in hot water. Spraying a carb with carb cleaner on the outside does very little except make it look good..

 

[isaaccarlson]

I don't consider a carb cleaned unless it is soaked in carb cleaner then rinsed in hot water. Spraying a carb with carb cleaner on the outside does very little except make it look good..

Right. I like to run a sized wire through every passage too. That way you know it's clean

 

[a. palmer jr.]

Right. I like to run a sized wire through every passage too. That way you know it's clean

I don't do that but I leave it in the cleaner a bit longer than the instructions say..