What's on your bench today?

[Dinosaw]

Hi Steve, Only teasing. I'ts difficult to put them in the wrong way as there's a locating pin on the end plate that goes through all the parts. If I pressurise the inlet it holds it fine but the pressure doesn't fall of fluctuate if I pull the engine over. This would be consistent with it not fuelling. Doing my head in quietly.....

[Darrin Turnbull]

Question for Spudulike,do you have a favorite saw.

[wisecobandit]

Hi Steve, Only teasing. I'ts difficult to put them in the wrong way as there's a locating pin on the end plate that goes through all the parts. If I pressurise the inlet it holds it fine but the pressure doesn't fall of fluctuate if I pull the engine over. This would be consistent with it not fuelling. Doing my head in quietly.....

Zama - C1T-EL41A

No 4 in the pic shows it does have a check valve. To check it I just use a short bit of fuel hose and put it tight against it and blow into it to allow air into the venturi. It should be free flowing. However you shouldn't be able to suck air back and if you can its failed. (normally tho you cant build up a great deal of pressure in the fuel bulb tho which gives the game away but sounds as yours is ok) Normally they are either a brass or silver looking plug that's pressed into the carb and flush fit with a small hole in the centre. There is a wafer thin bit of plastic in it that acts as a valve and carb cleaner can melt it and compressed air can blow it out of place.

[spudulike]

Question for Spudulike,do you have a favorite saw.

 

346XP.....357XP........MS200T.........254XP......066 but remember I mostly fix saws, port others and only cut my firewood.

 

The 346XP has to be the best sounding ported saw, the pickup is like no other:thumbup:

[wyk]

Soccer is spacer, lumped is pumped, bloody predictive text is not very predictive

 

I was trying to spell "impulse line" the other day on the phone and all I got was "GOOOOOOOOOOOOOOOOAAAAAAAAAAAAALLLLLLLLLLL!!!!!!!!!!!!!!!"

 

Terribly annoying.

[spudulike]

Zama - C1T-EL41A

No 4 in the pic shows it does have a check valve. To check it I just use a short bit of fuel hose and put it tight against it and blow into it to allow air into the venturi. It should be free flowing. However you shouldn't be able to suck air back and if you can its failed. (normally tho you cant build up a great deal of pressure in the fuel bulb tho which gives the game away but sounds as yours is ok) Normally they are either a brass or silver looking plug that's pressed into the carb and flush fit with a small hole in the centre. There is a wafer thin bit of plastic in it that acts as a valve and carb cleaner can melt it and compressed air can blow it out of place.

 

Lets get a couple of things clear and not saying you may not know this.........the "CHECK VALVE" is the one way valve that stops air being pulled down the high speed jet in to the diaphragm metering section of the carb - they are generally brass and alow the flow of fuel in to the throat of the carb when the carb throttle valve is opened and stops the reverse flow of air when the throttle is closed - with a straight jet, the idle would be somewhat non existant.

This is the check corectly outlined by Wiscobandit above.

 

The pressure check I was talking about was the "POP OFF" test and that is checking the needle valve is working correctly by putting a pressure gauge on the fuel inlet connector and making sure the needle is holding pressure. if it isn't, the symptoms are lack of starting and possible flooding of the engine.

[spudulike]

Hi Steve, Only teasing. I'ts difficult to put them in the wrong way as there's a locating pin on the end plate that goes through all the parts. If I pressurise the inlet it holds it fine but the pressure doesn't fall of fluctuate if I pull the engine over. This would be consistent with it not fuelling. Doing my head in quietly.....

 

I have seen a few carbs with the pumping diaphragm being placed next to the cover and the gasket being placed on the carb body - it gives a saw that will fire but little else!

 

One thing worth a try is to take all the fuel out of the carb pumping and metering sections - just remove the covers to drain it.

 

Replace the covers and fit it. Put the saw on full choke and pull it over 15 times and then strip the carb to see if there is fuel in both the pumping section AND the metering section - this will give an idea where the carb is failing. DON'T USE THE PRIMING BULB THOUGH!!!

 

worth checking the fuel line, tank breather and fuel filter as well!

[wisecobandit]

I have to say the chances are it may well be a simpler problem as Spud suggest.

As a matter of interest the diaphragm kit you used was it "specifically" for that saw or a generalised kit?

It pays to compare the 2 very carefully when replacing as some gaskets will "direct swap" but missing a hole etc. Also some come with 2 diaphragms one stiffer than the other and replace the more flexible one with a stiffer one sometimes causes issues with not pumping well or not pumping at all.

[wisecobandit]

I was trying to spell "impulse line" the other day on the phone and all I got was "GOOOOOOOOOOOOOOOOAAAAAAAAAAAAALLLLLLLLLLL!!!!!!!!!!!!!!!"

 

Terribly annoying.

 

Lol my phone somehow thinks "thing" should always be replaced with "thong" !!! Doesn't matter how much I delete it it still comes back! Its gonna catch me out 1 day and will be rather embarrassing!

[Dinosaw]

Thanks Guys, I'll dismantle it again in the morning. The service kit is right, not a generic one. Will let you know..