Echo 590 Timberwolf "H" setting

[Red97]

Thanks for your help. I will go with the HDA-191 jet but I have another idea, assuming the goal is to block or close this hole in the jet. Since the current HDA-268 jet has a .58 mm opening which equates to .022835 inches, I could use a 0-80 2A screw with a maximum minor diameter of .0442 inches and effectively plug the hole. This would eliminate having to swap out jets and I've found JB weld doesn't hold up in constant gasoline contact. Since the jet is made from brass, a short 0-80 screw should easily thread into the hole.

The goal is to block the hole in the bottom of the jet. The stock jet has to be in the correct position to line up with the feed hole in the carb body.

The 19X jet has a band machined and 2 feed holes to allow fuel flow regardless of the index. Just has to seat at the right depth, which has a bit of play as well.
Feel trying to insert a screw could allow debris to block the feed passage/damage the check valve.

Swapping the jet
Literally a 5-10 min job on the 590.

Remote AF cover/filter
Undo fuel/impulse
2 bolts (t27) to remove the carb
4 screws to remove bottom cover (metering/wet side).
Pin punch with flat face the jet into carb bore
Open throttle plate remove old jet
Tap in new jet
Reinstall.

Enjoy fully adjustable 590 carb

 

[sawfixer]

Thanks for the clarification. I was thinking of a main jet instead of the nozzle/check valve assembly. Please ignore the part Nos. I provided in my previous posting, as they were for a main jet which isn't applicable to this series of carb. The correct PN for the nozzle/check valve from Walbro is 86-578-1 or 1120-121-5404W.

 

[Team FAST]

This is a good thread. I think this explains why my saw was running so rich after the muffler mod/flow bench tests.

Thanks for the info. Red, can you re-post your pic of the carb mod?

 

[dpilot83]

Thanks for the info. Red, can you re-post your pic of the carb mod?

+1. Unfortunately Photobuckets new policies have really caused a lot of good pictures on forums to be lost

 

[Dave51]

I don't have a part number for the nozzle, but it was a direct fit from the hda 191. I'm sure most hda 19x carbs use the same nozzle.



You can see the hole in the brass nozzle. That is what needs to be closed off. The 191 nozzle dosent have that hole. Or you could use a dab of jb weld.

I fought with these carbs for weeks on my ported 590, pig rich with the H needle closed all the way. I finally swapped a hda 203 (off of a echo 670) that allowed me to tune where the saw wanted. Wanted to avoid having to buy a old carb for every 590.

With the modified 590 carb I am roughly 7/8 out @14,200

Started looking at the difference between the stock 590 carb and the 670 carb. Only major difference was the hole in the bottom of the main nozzle.

I would not recommend trying to remove and re install the 268 nozzle. I had one feed hole that has to line up exactly with the H feed in the carb body. Where the 191 nozzle has 2 feed holes in the side, and a machined band allowing flow, regardless of how it is installed.

If I put a 203 on my 590 mild mm what you suggest for starting point?and what's your at after tuneing?

 

[Red97]

If I put a 203 on my 590 mild mm what you suggest for starting point?and what's your at after tuneing?

1,1 on the screws should be a good start. And probably under 13.5k no load rpm.

 

[Dave51]

1,1 on the screws should be a good start. And probably under 13.5k no load rpm.

If I go with the 191 nozzle ,i pucnch out the brass with the hole in it or is nozzle underneath that?

 

[Red97]

If I go with the 191 nozzle ,i pucnch out the brass with the hole in it or is nozzle underneath that?

That is the nozzle. Get the part in your hand first. Knock one out of a junk carb first to get a feel for it. If you gall the bore, it will junk the carb.

 

[Dave51]

That is the nozzle. Get the part in your hand first. Knock one out of a junk carb first to get a feel for it. If you gall the bore, it will junk the carb.

Thanks your help is appreciated.

 

[lostone]

Red97 I am assuming you are talking about Walbro 86-578-1 check valve/Nozzle?

 

[Dave51]

Red97 I am assuming you are talking about Walbro 86-578-1 check valve/Nozzle?
View attachment 642159

Yes I got a couple of them . 268 nozzle was in there pretty tight but I got it out and put in the 191 nozzle . My metering lever is a little high I think I put a ruler across and it hit it but I wanted to play it safe and put back together.i set the idle got it tuned pretty good but it seems to rich for my likening.if the lever is a little to high won't it make it run rich?I pulled it again and going to lower the lever a tad and hope for the best! Any advice ? Thanks for your help I would be in the dark yet if not for all your friendly advice thanks again.

 

[Red97]

Yes I got a couple of them . 268 nozzle was in there pretty tight but I got it out and put in the 191 nozzle . My metering lever is a little high I think I put a ruler across and it hit it but I wanted to play it safe and put back together.i set the idle got it tuned pretty good but it seems to rich for my likening.if the lever is a little to high won't it make it run rich?I pulled it again and going to lower the lever a tad and hope for the best! Any advice ? Thanks for your help I would be in the dark yet if not for all your friendly advice thanks again.

With the nozzle swapped you should be able to lean the high side all the way out.

Play with the tune a bit more. After the swap high, low, and idle will need some adjustments.

 

[Dave51]

With the nozzle swapped you should be able to lean the high side all the way out.

Play with the tune a bit more. After the swap high, low, and idle will need some adjustments.

Got it in a pretty decent spot now took me some time to get tuned where I liked it.im a rookie tuner but it's cutting real good and idles nice I don't have a tach but tuneing h side in logs. I'm trying to keep it a tad rich! Boy lots a room for adjustment now!

 

[lostone]

I fought with these carbs for weeks on my ported 590, pig rich with the H needle closed all the way. I finally swapped a hda 203 (off of a echo 670) that allowed me to tune where the saw wanted. Wanted to avoid having to buy a old carb for every 590.

With the modified 590 carb I am roughly 7/8 out @14,200

Started looking at the difference between the stock 590 carb and the 670 carb. Only major difference was the hole in the bottom of the main nozzle.

So the hda 203 has everything lining up? you can get to the jets to adjust them just like hda 268 with the side cover on? Reason I ask is I can get a 203 for $60 plus $8 shipping new and I don't have to deal with swapping out the nozzle/valve. Or I can get a hda 316 for $71 plus $8 shipping new. Yes swapping out the nozzle will be cheaper.

 

[Dave51]

So the hda 203 has everything lining up? you can get to the jets to adjust them just like hda 268 with the side cover on? Reason I ask is I can get a 203 for $60 plus $8 shipping new and I don't have to deal with swapping out the nozzle/valve. Or I can get a hda 316 for $71 plus $8 shipping new. Yes swapping out the nozzle will be cheaper.

You can put the 203 on and pull caps off a Just as you like. The 268 high side is somewhat limited.i got alot info on here. Just research what you want.or replace the nozzle from a hda191 into the 268 then it's adjustable

 

[lostone]

Dave I'm asking if the adjusting screws are in the same location on the 203 as the 268 so it can be adjusted using the factory holes for adjusting. If not then I will just buy the 316 since I know it is the same as the 268. I can get the 203 cheaper.

Either way it may not matter, I ordered in the nozzle/valve and if it goes in fine then I have nothing to worry about BUT if something doesn't work out then I will be buying a diff carb.

 

[Dave51]

Dave I'm asking if the adjusting screws are in the same location on the 203 as the 268 so it can be adjusted using the factory holes for adjusting. If not then I will just buy the 316 since I know it is the same as the 268. I can get the 203 cheaper.

Either way it may not matter, I ordered in the nozzle/valve and if it goes in fine then I have nothing to worry about BUT if something doesn't work out then I will be buying a diff carb.

Ok sorry I misunderstood you.hope it all works out for you.i never installed the203 to know I went with nozzle replace. You said you might get the 316 I never knew it would work I just heard the 203 would.good luck.

 

[lostone]

316 is off of the cs-620P. My understanding is it never had the bypass that the 590 got on the 268.

 

[Dave51]

Where you order the carbs if I may ask that's a good price on them.

 

[lostone]

Where you order the carbs if I may ask that's a good price on them.

Pat's small engine Plus, I have never dealt with them and came across their site while doing a search for parts.