What's on your bench today?

[JAMIE1]

Fuel pipes were replaced at the dealers when the carb was cleaned.

Sometimes, but not always they bog down when tilted with exhaust side of engine facing ground and carb facing up.

The airfilter has been wet, though I haven't noticed it recently.

Metering valve is set level with the top of the body of the carb.

I'm glad it's not just me that can't work it out! Many thanks for the help so far.

 

Could be that the piston is worn. Worn piston skirts cause fuel to come back through the carb.

[WorcsWuss]

Quick question..... 019T.... Have changed the gaskets and diaphragms in the carb, reassembled everything, all went together well....

 

Now it's fuelled up, how long should it take for fuel to come through....?

I've pulled it over till I ran out of patience, took the plug out and can see / smell no evidence of fuel in the cylinder.

 

This is of course assuming I haven't somehow managed to block the carb during the cleaning process.....

 

Will winding out the low screw speed the job up....?

 

019T has a horrid arse about face design, to get to the carb the whole bloody saw needs to come apart, which makes troubleshooting painfully slow....

 

Thanks in advance...!

 

Edit.... Something's not right here.... it's all going to have to come apart again....

Is there a way to bench check the carb to see if fuel will flow through it....?

Edited November 6, 2012 by WorcsWuss

[GardenKit]

Quick question..... 019T.... Have changed the gaskets and diaphragms in the carb, reassembled everything, all went together well....

 

Now it's fuelled up, how long should it take for fuel to come through....?

I've pulled it over till I ran out of patience, took the plug out and can see / smell no evidence of fuel in the cylinder.

 

This is of course assuming I haven't somehow managed to block the carb during the cleaning process.....

 

Will winding out the low screw speed the job up....?

 

019T has a horrid arse about face design, to get to the carb the whole bloody saw needs to come apart, which makes troubleshooting painfully slow....

 

Thanks in advance...!

 

Edit.... Something's not right here.... it's all going to have to come apart again....

Is there a way to bench check the carb to see if fuel will flow through it....?

The fuel should come through within half a dozen pulls.

If it does'nt then something is amiss.

 

The carb has a fuel pump on one side, it is operated from 'pulse' from the crankcase.

So no fuel getting to the carb could be

1 no pulse ( damage pulse tube, leaking crank seals etc)

2 no pumping ( incorrect assy of pump membranes)

3 no suction ( leak in pickup hose or blocked pickup filter)

 

Fuel could be getting to carb, but not to inlet manifold

1 no way through metering valve ( incorrect assy of metering valve/diaphragm

2 no way out of metering chamber ( blocked jet)

3 no inlet suction to draw fuel from carb ventori ( crank seals, compression)

 

Try those for starters, also check for trapped or pinched fuel hoses

 

Good luck

[GardenKit]

Is there a way to bench check the carb to see if fuel will flow through it....?

 

Yes, you can use a pop tester. Its a 'must have' tool for any 2t techie. Its a little pump, you attach it to the pickup pipe, pump it up to the 'pop off, pressure, often around 15psi. This is the pressure that overcomes the spring pressure on the metering valve. Let it pop and repump to just under that pressure. The guage should hold steady. Crank the engine and the manifold vacuum should pull down the metering diaphragm, opening the meetering valve and allowing the pressure to drop.

[WorcsWuss]

Have you got a link to a pop tester....? Struggling to find one to buy!

 

The 019T is reed valve induction, the carb is buried at the front of the saw behind the fuel tank and under the chain brake... I can't see any impulse tubes anywhere, only pipe onto the carb I could see was the fuel line....?

 

I'm going to dismantle it again and whip the carb apart, make sure I haven't put it together in the wrong order... I have a niggly feeling I may have got my metering gasket & diaphragm the wrong way round... which may explain things....!

 

Have managed to find the exploded diagram on the Walbro site so will sit down at the kitchen table with the carb while the wife is at work and set about it!

[GardenKit]

Have you got a link to a pop tester....? Struggling to find one to buy!

 

The 019T is reed valve induction, the carb is buried at the front of the saw behind the fuel tank and under the chain brake... I can't see any impulse tubes anywhere, only pipe onto the carb I could see was the fuel line....?

 

I'm going to dismantle it again and whip the carb apart, make sure I haven't put it together in the wrong order... I have a niggly feeling I may have got my metering gasket & diaphragm the wrong way round... which may explain things....!

 

Have managed to find the exploded diagram on the Walbro site so will sit down at the kitchen table with the carb while the wife is at work and set about it!

My previous post was in general, not specific to your saw as I am not familiar with it. However, it looks like this saw (as with many others) takes its impulse from drillings in the crankcase and through the insulator direct into the carb (no tubes to perish).

You will see the little hole in these items. Make sure they line up and that the gaskets are correctly fitted so as not to block the hole. Also worth checking that the hole is clear into the crankcase.

 

I will check into the pop tester later in the morning and let you know.

[GardenKit]

My previous post was in general, not specific to your saw as I am not familiar with it. However, it looks like this saw (as with many others) takes its impulse from drillings in the crankcase and through the insulator direct into the carb (no tubes to perish).

You will see the little hole in these items. Make sure they line up and that the gaskets are correctly fitted so as not to block the hole. Also worth checking that the hole is clear into the crankcase.

 

I will check into the pop tester later in the morning and let you know.

My carb supplier does not have any pop testers at present, but this is the one you are looking for. I dont know if this is the best place to buy, or the right price, but its the thing you need.

Kart Carb Pop Off Tester Brand New Karting Best on Ebay | eBay

[mikerecike]

First proper post here - looks a great forum - loads of knowledge around - brill.

 

Trying to find a brake band for one of these - anybody know a UK supplier/dealer in brake bands? Can't believe how many houses I've been round.

 

 

 

I think the part no: is 301037. Frustraaaaaaaaaaating.

 

The other saw even lower down the food chain is a B&Q job - exactly same story - brake band - peerformance pro 42cccsa

 

Thanks folks

[Will H]

Here's the complete chain brake assembly for sale:

 

McCulloch MacCat 839 Petrol Chainsaw chainbrake & casing. Free post ! | eBay

 

You could use the whole housing or just rob the brake band...

[mikerecike]

Thanks a lot will - i saw that but don't really want to spend 15 quid for it if i can help it - and i presume that one's had a bit of use too. Reply much appreciated though.