AM WJ 69 mods

[Redfin]

Is there any success in trying to reseat a leaking welch?

 

[jmssaws]

Yup, leaky needle and seat. That is why I always pressure test a carb before installing it.

What psi should it pop at?

 

[srcarr52]

What psi should it pop at?

These are probably above 20 psi. More importantly check that it holds 10 psi, and if you tap the lever it re-seats without leaking.

 

[Terry Syd]

That's a pretty impressive leak on the carb, obviously there is pressure in the tank. So what kind of tank vent does it have? Is it just a duck-bill or maybe it is completely plugged?

I'm not a big fan of EPA approved tank vents. Mine tend to get gutted so the tank is vented to atmospheric pressure. Then I know the fuel delivery to the carb is consistent, instead of pressurized one time and a vacuum the next.

 

[Terry Syd]

More importantly check that it holds 10 psi, and if you tap the lever it re-seats without leaking.

That's the important part, making sure the needle re-seats without leaking. - The "pop off" pressure is irrelevant and is a way overrated concept that has taken on a life of its own. I think it started from some of the Kart forums. For example, you can have two carbs with two different size metering orifices. One of the orifices can be twice the size (area) of the other. The bigger orifice carb will have HALF the 'pop off' pressure of the smaller one as the pressure can work on a larger area. - It is the metering diaphragm that 'lifts' the needle off the seat.

 

[CR888]

What psi should it pop at?

It can vary carb to carb on the same model usually 5-20psi but the exact number or target is not the point, more the fact that it does pop off or not is my understanding. Its quite un natural to put 20-30 psi through the carb and damge can result to diaphrams etc.

 

[Deets066]

That's a pretty impressive leak on the carb, obviously there is pressure in the tank. So what kind of tank vent does it have? Is it just a duck-bill or maybe it is completely plugged?

I'm not a big fan of EPA approved tank vents. Mine tend to get gutted so the tank is vented to atmospheric pressure. Then I know the fuel delivery to the carb is consistent, instead of pressurized one time and a vacuum the next.

How would you gut a tank vent without it leaking?

 

[Terry Syd]

On my 365BB I removed the duck-bill valve and packed the inside with steel wool. The vent does leak when I am putting fuel in the tank, perhaps around 1/2 teaspoon of fuel. It will stop leaking as soon as I get the fuel cap on. The bit of fuel leaking through the vent makes it a 'self-cleaning' vent.

I didn't have to gut the vent on the 029, it was already just a piece of hose with a screw on top.

I don't know how that vent on your saw works. It looks like it is just a hooked piece of pipe with a filter element around it. Is there a valve in there somewhere that can cause the tank to pressurize?

 

[huskihl]

I think that orange rubber is a one way valve, isn't it? My 036 has a one way in it. Go out at 35° to work on the saw. After an hour the shop warms up and I pull the hose off the carb.

 

[Terry Syd]

If so, then you could just put a straight piece of tubing on it with a screw on the end - like the 029 vent.

 

[Chris Zautner]

On my 365BB I removed the duck-bill valve and packed the inside with steel wool. The vent does leak when I am putting fuel in the tank, perhaps around 1/2 teaspoon of fuel. It will stop leaking as soon as I get the fuel cap on. The bit of fuel leaking through the vent makes it a 'self-cleaning' vent.

I didn't have to gut the vent on the 029, it was already just a piece of hose with a screw on top.

I don't know how that vent on your saw works. It looks like it is just a hooked piece of pipe with a filter element around it. Is there a valve in there somewhere that can cause the tank to pressurize?

there no regular screw they are a grub screw

 

[Chris Zautner]

i will get you a picture of the vent tomorrow Keith.

 

[Deets066]

I'm going to try another carb before I re engineer the tank vent.

The vent is a small rubber flap that opens one way but closes the other

 

[drf256]

I've yet to have a carb on mine that wouldn't run out of fuel on a long cut so I'm all ears to deeter.

I've tried drilling every hole i can drill without success.

Your issue may certainly be heat. You like comp and timing advance, I do too. But the saw leans as the head heats up.

Try dialing back your timing for shiz and giggles. See what happens.

If you can mark out where, if any, room exists for larger fins. I'd be glad to extend a few for you J.

Uncork you tank vent too. See if that changes things.

Of course, one at a time so you know what worked.

Ok, only thing I did is lower the metering arm to sit flush. It seems to sound a little better coming out of the cut and doesn't race before returning to an idle.

But after it idles for a bit and you blip the throttle it bogs. It died the last time when I blipped the throttle.

I checked rpm and I was 13,850 let it idle for 5-6 seconds and hit the throttle and it died.

You seem to have found your issue, but as you likely know, I had that problem on an 026 because of the timing advance. The advance made it wanna be super rich to get the idle down. Then it would pool fuel and die when I hit it, but only after a period of time idling.

 

[Deets066]

I never had an issue before so I doubt mine is the timing. I did however take my 046 too far with timing and have the same problem as you did. I dialed it back and it defiantly was the problem

 

[drf256]

There probably a soft spot Deets.

And it also varies from saw to saw. I'm about to change the coil in mine. I have an 024S coil and an 026 flywheel. For all I know, the timing may be well advanced at the stock position.

I've done the same timing advance on at least 5 other 026's with zero problems.

 

[Mastermind]

Is there any success in trying to reseat a leaking welch?

Tap on it with a flat punch, then paint it with nail polish.

 

[jmssaws]

I just got a set of Kool carb punches for that.

 

[Keith Gandy]

I just got a set of Kool carb punches for that.

Pics?

 

[Keith Gandy]

I need to study carbs more. 9/10 of all trimmers and blowers in my shop r carb/fuel related.