carb boring? MS 361

[Farm Pro]

Has anyone bored out the carb for a Stihl 361? Going to doa muffler mod and was thinking "Hey, why not open the carb too". Can it be done?

 

[Crofter]

I would not be quick to jump into that. Some carbs have a semi fixed high speed circuit and the needle only has a small range of control. When you bore out the carb usually the venturi area is enlarged and that changes the pressure differential away from design and you need larger opening of the HS fuel circuit to supply even the same amount of fuel. Some carbs have enough range to accommodate it and others need orifices redrilled. Sometimes you expose fuel passages when you remove metal also, so before you do it talk to someone who has done it to that particular carb and be shy of second or third hand info on this. Unless you do considerably advanced mods to the engine porting the extra carb bore area will likely not be any advantage anyway and bored carbs can be a lot touchier to tune.

 

[Lakeside53]

+1


"opening up the carb" after a muffler mod is done by adjusting the H&L screws... if all you're doing is the muffler, you don't need a bigger carb.

 

[DarylB]

A bigger carb would be cheaper, safer, & easier to tune.