Stihl 021

[Kidneycutter]

Hi,
I have a leak on the manifold/rubber boot that connects to the carb. Just taken the housing off and unsure wether I need to pull the engine out to take the shroud off .

 

[HarleyT]

How do you know there is a leak there?

 

[Kidneycutter]

How do you know there is a leak there?

Because I’ve just bought a mityvac tester and bubbles are pouring out where the boot meets the cylinder.
anyway i pulled it apart and replaced and it seems to be fine. Problem now is my 230 which runs a little funny And is difficult to tune. Put the tester on and it has a leak on the cylinder base - so will be investigating that tomorrow.
at which point can you bust the seals with a pressure/vacuum test I’ve been going to 7psi - it says 5psi in the manual.
I wish I’d bought one of these testers a long time ago!

 

[Binthewoods]

Because I’ve just bought a mityvac tester and bubbles are pouring out where the boot meets the cylinder.
anyway i pulled it apart and replaced and it seems to be fine. Problem now is my 230 which runs a little funny And is difficult to tune. Put the tester on and it has a leak on the cylinder base - so will be investigating that tomorrow.
at which point can you bust the seals with a pressure/vacuum test I’ve been going to 7psi - it says 5psi in the manual.
I wish I’d bought one of these testers a long time ago!

Yeah, it beats the hell out of guessing doesn't it

 

[SteveSr]

Hi,
I have a leak on the manifold/rubber boot that connects to the carb. Just taken the housing off and unsure wether I need to pull the engine out to take the shroud off .

These 1123 series saws (021, 023, 025) are known to leak around the cylinder/pan joint. Best thing is to pull it apart, replace the seals, and put it all back together with some Dirko. Problem solved... at least for a couple of decades!

 

[Benwa]

Because I’ve just bought a mityvac tester and bubbles are pouring out where the boot meets the cylinder.
anyway i pulled it apart and replaced and it seems to be fine. Problem now is my 230 which runs a little funny And is difficult to tune. Put the tester on and it has a leak on the cylinder base - so will be investigating that tomorrow.
at which point can you bust the seals with a pressure/vacuum test I’ve been going to 7psi - it says 5psi in the manual.
I wish I’d bought one of these testers a long time ago!

You aren't the first one. They ALL leak there haha. Seriously though, very common issue. I've had more than 5 that all leaked there at the cylinder base. They leak at the front part where the cylinder meets the bearing cup. They leak a little to flywheel side from center. Anyway, full teardown and reseal of the cylinder and bearing cup fixes them right up. Might as well throw a fresh set of crank seals in at the same time. As far a testing, you're just fine at 7psi. Even 10psi isn't going to do any damage. 7 is pretty much the "standard" that everyone uses. Keep up the good work! Knowledge is power. Kinda fun ain't it!!