Stihl 026 - fuel leaking from exhaust

[TommyT]

• #1

I have just rebuilt another 026, but this time round it has fuel oozing out of the exhaust whenever I try and pull it over. It has a new piston, rings and cylinder along with a new exhaust gasket. 
I've tried three different carburettors all with new carb kits, but exactly the same result. When I take off the carb the impulse line runs with fuel for nearly a couple of seconds. 
New coil fitted so it has a good spark. 
Could it be that the piston rings are not seated correctly?
Any advice would be really helpful.

[ChrisNewport]

It must be the needle in the carb letting fuel through, are they the correct carb kits?

[TommyT]

Yes the same ones I use when I rebuild all my 026’s. 
This is the first for this fault. It seems strange how much fuel runs back out I’m the impulse line after the carb has been removed. 

[peatff]

Not familiar with 026 but can you fit the fuel and impulse lines the wrong way round, get them mixed up ?

[TommyT]

No you can’t with this particular model of saw. This is about my 6th rebuild and don’t think it’s a carb issue as all three are doing the exact same thing. 

[billpierce]

Have you tried pulling the plug turning upside down and pulling over. Pull the air filter off and blow everything out with an airline. Could be just massively flooded? Does it feel likenits hydro locked?

[TommyT]

I did try it upside down but no joy. 
What do you mean by hydro locked?

[Stubby]

Does it fire at all ?  If not it may have sheared the flywheel key putting it out of time hence all the fuel ?

[billpierce]

I did try it upside down but no joy. 
What do you mean by hydro locked?

With the plug out? Have had saws so over fuelled the crank becomes full of fuel and they become hard or impossible to pull over.

If your using a known good carb and you have a spark and you know compression is good, i would though blow out the cylinder, carb boot, air filter and exhaust with a compressor, refit spark if its not firing or soaking plug is soaked then its either over fuelling or you didnt clear enough fuel out.

[AngrySquirrel]

7 hours ago, TommyT said:

I did try it upside down but no joy. 
What do you mean by hydro locked?

Hydro locked is when more wetness than can compress so what we termed in motor trade as Hydraulicd so piston can't go past it only back down bore which can end up with bent rods/bust pistons same thing happens when roads are flooded and cars suck water into manifold.

Take plug up blow out/up end and is plug wet? is that impulse line blocked/collapsing? as things like that can syphon back if pressure is wrong!