High Quality Chainsaw Bars Husqvarna Toys

Low speed screw keeps backing out on Walbro carb

GBertolet

Well-Known OPE Member
Local time
9:28 AM
User ID
10142
Joined
Aug 6, 2019
Messages
123
Reaction score
80
Location
PA
Country flag
The low speed screw keeps backing out on my Poulan 3700 chainsaw. I have to keep a small screwdriver in my back pocket while cutting, to periodicaly turn it back in. Just backing out a 1/4 turn, will make the saw want to stall out at idle. Other than this issue, the saw runs fine. Are there any tricks to keep the adjustment screw to stay put?
 

smokey7

Pinnacle OPE Member
Local time
9:28 AM
User ID
761
Joined
Feb 3, 2016
Messages
1,532
Reaction score
3,549
Location
Detroit
Country flag
I've used loctite vibratite or regular blue.
 

67L36Driver

Here For The Long Haul!
Local time
8:28 AM
User ID
596
Joined
Jan 18, 2016
Messages
9,389
Reaction score
39,267
Location
Missouri
Country flag
Iffin you don’t find a spring, use the wife’s hot glue gun. [emoji108]
 

GBertolet

Well-Known OPE Member
Local time
9:28 AM
User ID
10142
Joined
Aug 6, 2019
Messages
123
Reaction score
80
Location
PA
Country flag
The screw does have a spring on it.
 

Al Smith

Here For The Long Haul!
Local time
9:28 AM
User ID
537
Joined
Jan 14, 2016
Messages
6,095
Reaction score
13,457
Location
North western Ohio
Country flag
It's kind of radical but you can use a sharp prick punch or an awl to dimple a few places around the screw .Don't be beating on it with a 4 pound ball peen though .Lightly .
 

legdelimber

Pinnacle OPE Member
Local time
9:28 AM
User ID
8391
Joined
Jan 14, 2019
Messages
562
Reaction score
1,321
Location
N.C.
Country flag
First thing, Make sure the threads on both the screw and inside the carb body are in good condition, not wallowed or partially stripped.

Then make sure that the spring is in good shape and not bent or mashed.
Then make sure that little washer is nice and flat. Not rough or anything that would damage the O-ring or spring end.

Make sure the O-ring and washer are matched in size and then that they fit the screw and carb body.

Then make sure the washer is between the end of the spring and the O-ring.
Then of course the O-ring is under the washer, against the carb body.
Easy to mix it up when we're in a hurry to get back to the wood.
If the O-ring is mashed out or ragged, it won't help much either.
 

Al Smith

Here For The Long Haul!
Local time
9:28 AM
User ID
537
Joined
Jan 14, 2016
Messages
6,095
Reaction score
13,457
Location
North western Ohio
Country flag
Another old trick .Take a small ball bearing ,place it in the hole and tap it to deform the first threads .Now don't thump it like you are forging a horse shoe ,tap .Small hammer .
 
Top