Stihl ts420 fuel flow

[ian march]

As a new member it is gratifying that all you guys and now me are here to help one another. Keep up the good work. PROBLEM:- I am looking for a manual on two machines 1:- ts 420 saw, rebuilt the engine but having carb problem. 2: 020T chainsaw that needs rebuilding. I am hoping for a copy of the service manuals for both if possible. On the ts420 I need to know if the "welsh plug" on the slow mixture side is necessary and how the fuel lines should be connected. Any help would be appreciated.

 

[AVB]

if you're referring to the welch that looks like a lollipop then yes it is necessary otherwise you will flooding problems.

As for the service manuals please post a request in the manual forum and Ray will probably send you the two manuals.

 

[ian march]

many thanks for the reply. Do you by any chance know the fuel pipe routing? Unfortunately the machine was given to me in pieces and the way the carb was plumbed just does not make sense to me. I will also put the manual request in the correct forum. Again many thanks

 

[AVB]

The port on the main cube should be the pickup (fuel in) port. And others should as follows on the air head:

 

[ian march]

Sorry but I do not follow there are two connectors from a unit on the tank, two on the primer and three on the carb(two at the top, one at the pump side of the carb) the fuel return you note was connected to the filter box? You consenator note what is that

 

[AVB]

The consenator is basically like the impulse line but being as secondary. The primer pulls fuel and air through the carb so that would be connect the fuel return post on and sends fuel back to the fuel tank. THe primer is actually meant to remove air from the carburetor fuel system. Fuel inlet should be connected to the fuel line that has the fuel filter on it.

A lot inexperience guys thinks the primer pushes fuel into carburetor when it is just the opposite.

 

[ian march]

This is great and making more sense with one small question. I now have the manual from Ray and just to verify, the manual appears to have the compensator line and the fuel return line(back to the primer bulb) reverse to what your sketch shows. ?? Or is the manual incorrect??

 

[ian march]

Thanks to you AVB I got it done. just got to find a welch plug and glue it in with something. I hope epoxy will work

 

[AVB]

Welch plugs are normally dome until you install them by flattening the dome area. Zama actually have a set punches for doing this as they are size to fit the different welch plugs but they are a little expensive for anyone doing one time repairs so using an appropriate size punch making several punches to flatten the welch is an option.

I know Zama recommend sealing them but most I have installed are tight fitting and no sealant was needed.

PN ZTK101 for tool kit part number reference.

 

[ian march]

Great picture, I am sure I can fabricate one to fit, I do rebuild motorcycle race engines so I have a pretty decently equipped shop.
Again my friend I am in your debt. This has certainly been an experience of "pay forward"