AM WJ 69 mods

[Deets066]

Erratic idle and changing tune like that is an indication of a small air leak. I had an 064 that was like that and it turned out someone had mix matched case sides and there was a slight step between them which was causing the base gasket not to seal when warm.

I've also seen where the saw will run fine up top but drown in fuel at idle to the point that the low side needle doesn't do much. It was because the needle in the carb would not seal properly and keeps letting a little fuel in, at WOT it wasn't enough to cause an issue. Have you put pressure into the carb and made sure it could hold at least 10psi with the needle?

I also ran into a 066 that would start, idle, run for 1/2 cut and die and wouldn't restart till you choked it. It had a plugged impulse barb in the case and with the choke set it had enough vacuum from the venturi to pull fuel into the carb, 1/2 cut and it would drain the carb.

This saw ran perfect before this carb was installed.

 

[jmssaws]

This saw ran perfect before this carb was installed.

Put the other carb back on it.

 

[jmssaws]

Mine has ran that way with every carb.

 

[Deets066]

Put the other carb back on it.

Welch plug is leakin

 

[Deets066]

Got an .020 copper shim I'm gunna stick under the spring

 

[srcarr52]

Welch plug is leakin

Sounds like the new carb has the same problem then.

 

[srcarr52]

Mine has ran that way with every carb.

I'd be looking for a vacuum leak or a partially plugged impulse line, fuel line or tank vent.

 

[Deets066]

Sounds like the new carb has the same problem then.

Welch plug was leakin on my Walbro, it ran like above in the vid I just posted, and one day I went to start it and it flooded, bad in just a few pulls. Fuel pouring out the muffler and filled the case completely.

I got it to run after that but it was a crap shoot if it would flood or not

 

[Deets066]

I posted a pic of the sealer coming off around the Welch plug on page 1

 

[srcarr52]

Welch plug was leakin on my Walbro, it ran like above in the vid I just posted, and one day I went to start it and it flooded, bad in just a few pulls. Fuel pouring out the muffler and filled the case completely. View attachment 16234

I got it to run after that but it was a crap shoot if it would flood or not

Leaking welch plugs don't cause massive flooding like that unless they have completely fell out. That kind of behavior is more due to a needle/seat that wont seal or a very weak spring and the pressure in the tank due to changes in temperature pushed fuel into the cylinder while the saw is being stored.

 

[Deets066]

Leaking welch plugs don't cause massive flooding like that unless they have completely fell out. That kind of behavior is more due to a needle/seat that wont seal or a very weak spring and the pressure in the tank due to changes in temperature pushed fuel into the cylinder while the saw is being stored.

So a new needle and spring would most likely fix it then. That's good to know, I would still like to get this AM carb runnin the way it should, just cuz.

 

[srcarr52]

So a new needle and spring would most likely fix it then. That's good to know, I would still like to get this AM carb runnin the way it should, just cuz.

That should fix the old carb.

 

[Deets066]

Shim must be too much in this AM carb, the saw won't fire at all, even tried the arm back at flush with no luck

 

[srcarr52]

Did you check how much the shim effected your pop off pressure?

 

[Deets066]

Did you check how much the shim effected your pop off pressure?

I set the height after the shim was installed

 

[Deets066]

That should fix the old carb.

Welp, I put a new needle in and a .010 shim under the spring, metering arm is just above flush. Sounded ok, little bog on the low end but I figured I could lower the metering arm back down a little to sit flush. Looked into the V Stack and this is what I saw.

 

[srcarr52]

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

 

[Deets066]

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

It's somthin I'm gunna start doin

 

[srcarr52]

It's somthin I'm gunna start doin

It will save you a lot of headaches and extra trips to the test log.

 

[big t double]

the drips...looks like your carb got burnt by gonorrhea. ol dirty bastard style. your welcome for this highly informative and helpful post.