Stihl TS410 primer bulb not working

[Welderpaul]

Saw works perfectly, or rather did a fortnight ago when I last used it.
Can pump away on the primer bulb and it doesn't pull petrol into it. No obvious leaks and the bulb itself looks fine, quite new infact.

Took the filler cap off to check no airlock.

Any ideas?

 

[angellonewolf]

cheak the fuel hose if theres a crack in the pipe all it will do is pull in air

 

[angellonewolf]

calling @JOEPRO

 

[roofman]

Saw works perfectly, or rather did a fortnight ago when I last used it.
Can pump away on the primer bulb and it doesn't pull petrol into it. No obvious leaks and the bulb itself looks fine, quite new infact.

Took the filler cap off to check no airlock.

Any ideas?

check the fuel pipe has not inverted inside tank...best way to check 1st is fill to the brim with fuel to see if it draws.

 

[angellonewolf]

vid if needed

 

[JOEPRO]

calling @JOEPRO

First thing to check is all the fuel lines to make sure they are 100% crack free and in good condition. Then replace the primer bulb too if suspect, the parts are inexpensive.

 

[Kram]

Same problem on my Mcculloch cs340. Hoses and bulb are perfect. With a brimmed tank it squirts into the tank but no fuel. It appears these have a one way valve and the problem can be in the carb. Mine is in bits and consuming my shed floor space while I await motivation. In the meantime. I have a cs2511, 020T and g372xp to use. However the cs340 was a useful saw to abuse for hedge trimming etc..

Odd as this happened before, and after a lot of swearing, it eventually just worked and I had a few days use out of it before it happened again after storage.

 

[Welderpaul]

Fair to say i stripped it down. Why Stihl design a saw that you can't take the carb off the back, you have to take everything off the front end - Everything attaches to the plastic chasis and the carb is trapped between ths and the engine

Non of the fuel pipes leak, nothing obviously untoward. Set up as the below pic, new primer bulb (The right way round) Fuel tank full, it doesnt pump anything......even if I close off the open ends of the fuel pipes. Surely it should be doing something?

I've not looked at the carb yet.

 

[JOEPRO]

Fair to say i stripped it down. Why Stihl design a saw that you can't take the carb off the back, you have to take everything off the front end - Everything attaches to the plastic chasis and the carb is trapped between ths and the engine

Non of the fuel pipes leak, nothing obviously untoward. Set up as the below pic, new primer bulb (The right way round) Fuel tank full, it doesnt pump anything......even if I close off the open ends of the fuel pipes. Surely it should be doing something?

I've not looked at the carb yet.
View attachment 452824View attachment 452825

Have you popped out the plastic bung where the fuel lines connect to and check the hose and filter inside the tank itself? One of then must be cracked and therefore not taking up fuel.

 

[roofman]

Make sure the in-tank filter which is also a weight is fulling to bottom of tank and not trapped inverted.

 

[Welderpaul]

Have you popped out the plastic bung where the fuel lines connect to and check the hose and filter inside the tank itself? One of then must be cracked and therefore not taking up fuel.

Yes, took the bung out, the bung, pipe and filter all look fine.

 

[Welderpaul]

Make sure the in-tank filter which is also a weight is fulling to bottom of tank and not trapped inverted.

Yep

 

[8ob]

The primers have a non return valve, they dont really work unless they are wet, I would suggest squirting a few drops of fuel into the inlet of the primer with a syringe.

Bob

 

[Welderpaul]

The primers have a non return valve, they dont really work unless they are wet, I would suggest squirting a few drops of fuel into the inlet of the primer with a syringe.

Bob

I rebuilt the carb tonight, gave the bulb a squirt as suggested and it started first pull. I think you might just have been right Mr Bob.