HELP! 345 to 346 swap

[Jusgunn3]

This is what it looked like when I pulled the jug today View attachment 457085

View attachment 457084

Nice lookin jug

 

[Shane¹]

Is that impulse hose kinked? They kinda need to be OEM with the loop in order not to

It is the OEM line off my 346. I swapped them and symptoms stayed the same and the 346 ran fine with the other line

 

[Ketchup]

Hard to say if you have a problem in these spots, but the PTO side doesn’t show much sealant (black arrows) and there is a fair bit of sealant near the pulse that could interfere (red arrows).

 

[Stump Shot]

Hard to say if you have a problem in these spots, but the PTO side doesn’t show much sealant (black arrows) and there is a fair bit of sealant near the pulse that could interfere (red arrows).

View attachment 457146

Not overly surprising to have different thicknesses of schmoo, when you consider that the base adapters are notorious for warping.

 

[Nitris223]

Did you grind down the plastic ribs on the right side of the case so the cylinder does not touch the side.
If you have a base gasket , maybe try running it with just to see if it makes any difference. Could be a slight warp in the bearing cap or the plastic case itself. But you did say it passed a leak and vacuum test. It could be developing a leak when it all warms up after a few cuts.

 

[Jusgunn3]

Throw a gasket in after cleaning up all the schmootz, might tell you if it was lack of sealing on that pto side.

 

[Shane¹]

Throw a gasket in after cleaning up all the schmootz, might tell you if it was lack of sealing on that pto side.

That's a good idea if backing off the timing a little doesn't help I may take it back apart and put a gasket in it just to rule it out

 

[Coupe]

Sounds a bit of a strange one. You would almost think it's sucking air in when it heats up
and were it would be hard to say as you have done most of the tests. Also sounds like you have
swapped coils so would think that should cover the spark side. The only thing that may be
worth a try is pull the wire on your on/off switch. May be it could be leaking and upset your spark
but I would think it would may be miss. Had a mate bring a stihl around that was causing him a
bit of trouble. When he run it for a while cutting it would slowly start to die and when turned off
would not start again so I got it hot turned it off and yep same thing. Put my little spark tester in the
line and yes no spark, let it cool down and away it went.(coil was breaking down when hot) New secondhand
coil and away it went.

 

[Shane¹]

Update got these saws all squared away not sure still what was causing all the issues or if it was a combination of a couple things. In the end I found intake was not as tight as I thought it should be and ring gap was really high already for some reason on a new piston and cylinder kit so I put a new piston and ring in it and it's all good now

 

[farminkarman]

Update got these saws all squared away not sure still what was causing all the issues or if it was a combination of a couple things. In the end I found intake was not as tight as I thought it should be and ring gap was really high already for some reason on a new piston and cylinder kit so I put a new piston and ring in it and it's all good now

Glad to hear you got it figured out!

 

[59billy]

Sometimes persistence is the secret ingredient. I need more of it.