Fuel starvation at idle?

[merc_man]

You have a pressur / vac tester. Id double check for an air leak.

Sent from my SM-J320W8 using Tapatalk

 

[WoodShed]

Hmm,

Ive had 5 or so 590's some of them fought me, but nothing like that.

Can't say for certain. Possible air leak.? Check the impulse hose for nicks/holes.
What did you use to seal the jug?

I Don't touch the idle screw, maybe just set it a bit high until I get the low close. Fix the idle then check the H tune.

Saw didn't do that before your mods?

I used Ducati bond which is Three Bond 1207B. Also cleaned the cases and jug well with brake clean.

I checked the hoses, but could be something I can't see.

 

[WoodShed]

Unfortunately I do not have a vac/pressure tester. Would a shop/dealer be able to check?

Is the impulse line on top of the carb?

I didn't have the problem before.

 

[Red97]

Unfortunately I do not have a vac/pressure tester. Would a shop/dealer be able to check?

Is the impulse line on top of the carb?

I didn't have the problem before.

Dealer may do it for ya, but likely cost the same as buying a mityvac and an innertube/gorilla tape.

Yes impulse is on top the the carb, other side is in the case below the intake boot.

 

[WoodShed]

Ha. Actually I think I do have one of those somewhere! I guess I was thinking about a leakdown tester.

I'll have to do some research on how to mock it up. I guess plug the intake and exhaust is a start.

So is the impulse line a static air source?

 

[tree monkey]

change the pump diaphragm , if that's not it then it's the acc pump

 

[WoodShed]

change the pump diaphragm , if that's not it then it's the acc pump

I'll change the pump diaphragm when the kit comes in on Wednesday.

Can the acc pump be replaced, or is that a carb replacement?

 

[jmssaws]

I had a wj6a on a 064 today that ran perfect but after 10 second idle it would start to lean surge and die regardless of carb setting.

It was the fuel pump.

 

[JimmyD]

I'll change the pump diaphragm when the kit comes in on Wednesday.

Can the acc pump be replaced, or is that a carb replacement?

Hi woodshed, did you ever solve this issue? I have exactly the same problem with my saw. I've replaced the pump diaphragm (albeit aftermarket) and it does not seem to have made a difference. Saw runs fine otherwise, just starts idling high when left for a few seconds after cutting. Cheers

 

[JimmyD]

In case this helps anyone else, I believe I have solved the issue (at least in my case). The saw is an Echo 620sx. The metering lever was set too low, which results in a lean condition which is most obvious at idle. I adjusted it according to the Walbro HDA manual. I've not tuned the saw in wood since adjusting the metering lever, but I left it idling for approx 1 minute and it did so perfectly, whereas previously the idle would have raced after about 5-10 seconds.

I did also notice the high needle needed to be screwed out quite far to get good performance, so hopefully this too will be resolved when I get round to tuning it properly again. I bought the saw used with this issue.