Stihl 028 excessive flooding issue

[AdirondackStihl2.0]

Just got this 028 back to running condition and then this happens.

The saw excessively floods on the 1st or 2nd pull and sprays out of the exhaust.

I just did an entire carb rebuild

Carb is a WT16B

Does anyone have any idea as to what’s going on?

 

[EFSM]

I would suspect that the carburetor is leaking through. Do you have the tools to pressure test the carburetor? If you changed the needle, sometimes a new needle seals worse than an old one if the seat is worn. I just had a MS260 that had a pitted/corroded seat (despite being chrome or stainless, whatever the shiny ones are made out of). I would guess that 028 has a brass seat, which can wear and corrode much worse than the newer shiny ones.
Or a defective pump diaphragm could be causing the same issue.

 

[EFSM]

As far as I know, the seats are not available as a separate repair item. When I need one, I punch one out of an old carburetor and install it at the same depth.

 

[hacskaroly]

In the second pic, looks like you have a bur on your rocker arm, if so, need to file it flat, the diaphragm could be holding the rocker arm (needle) open just a little, enough to flood.

When starting, are you using full choke or not? If you are and you are in a flooded situation, put it in run mode (no choke) and give it about 20-30 pulls, see if it clears the flood and starts. I would file that bur first or you may just be going back and forth with it.

 

[el33t]

Is the lever about 1.65 mm below the carb body casting?

 

[Adirondackstihl]

In the second pic, looks like you have a bur on your rocker arm, if so, need to file it flat, the diaphragm could be holding the rocker arm (needle) open just a little, enough to flood.

When starting, are you using full choke or not? If you are and you are in a flooded situation, put it in run mode (no choke) and give it about 20-30 pulls, see if it clears the flood and starts. I would file that bur first or you may just be going back and forth with it.

View attachment 463023

I picked up on that and he has removed the burr.

Is the lever about 1.65 mm below the carb body casting?

View attachment 463033

the metering lever is flush with the body of the carb as depicted in the diagram

 

[Adirondackstihl]

I would suspect that the carburetor is leaking through. Do you have the tools to pressure test the carburetor? If you changed the needle, sometimes a new needle seals worse than an old one if the seat is worn. I just had a MS260 that had a pitted/corroded seat (despite being chrome or stainless, whatever the shiny ones are made out of). I would guess that 028 has a brass seat, which can wear and corrode much worse than the newer shiny ones.
Or a defective pump diaphragm could be causing the same issue.

The carb is definitely leaking.
It’s not the welsh plug as I sealed that as a precautionary measure.

Being a STENs kit, it is possible that the metering diaphragm is out of spec, I assume that’s what you meant, not the pump diaphragm.

I no longer have a MityVac to check for leaks or pop-off

 

[el33t]

the metering lever is flush with the body of the carb as depicted in the diagram

I'm not sure I understood you correctly. Is the lever flush with the body or 1.65mm below?

 

[EFSM]

The carb is definitely leaking.
It’s not the welsh plug as I sealed that as a precautionary measure.

Being a STENs kit, it is possible that the metering diaphragm is out of spec, I assume that’s what you meant, not the pump diaphragm.

I no longer have a MityVac to check for leaks or pop-off

No, I meant the pump diaphragm. If there is a perforation in the pulse chamber area, it will leak into the crankcase. That's not very likely except with the thin plastic style diaphragm.

 

[EFSM]

I'm not sure I understood you correctly. Is the lever flush with the body or 1.65mm below?

You could say "level with the floor of the metering chamber"

 

[gorilla]

Hi, I am a fingerprint expert, and judging by your second picture, you are Lee Harvey Oswald, could you pop into your local sherrif's
office at your own convenience, as we are a bit busy at the moment. thanks for your co-operation. FBI

 

[Adirondackstihl]

Problem solved
Stens kits are junk

 

[Adirondackstihl]

 

[EFSM]

That pump diaphragm is incorrect. It should be solid instead of having the large cut-out on top. Usually there are more than one kind that come in the kits so the kits work on more models.

 

[Sloughfoot]

That pump diaphragm is incorrect. It should be solid instead of having the large cut-out on top. Usually there are more than one kind that come in the kits so the kits work on more models.

Like #12 in the ipl above?

 

[el33t]

Like #12 in the ipl above?

Yes. D10-WAT kit:

 

[el33t]

Problem solved
Stens kits are junk

Is this a 615-443 kit?

Shopping

www.stens.com

 

[topher]

Tank vent blocked ???? this would pressurise the fuel system

 

[EFSM]

Like #12 in the ipl above?

Yes.