Husqvarna 435 won’t stay running

[Ronie]

Yes, turning counter clockwise should slow the idle down. That could be the whole problem.

 

[Ronie]

I just looked at the workshop manual and the initial carb settings are one turn out

 

[Ronie]

I PM you the workshop manual

 

[Deleted member 117362]

Tank vent plugged? Muffler plugged?

 

[scottr]

435 not 345 .

 

[kur1j]

Yes, turning counter clockwise should slow the idle down. That could be the whole problem.

Thanks. I *might* have discovered something....the following picture is the throttle butterfly. Hopefully you can see it in the pictures, but the little white thing on the left side in the hole is the idle screw. There’s no way it is doing anything. Or at least I don’t see how. If it’s supposed to mechanically move the butterfly it’s not going to since it’s not even touching it. If it’s supposed to operate by only letting in a touch more air for every turn, I don’t see how that will do anything since i’m running it with the air filter off and it’s just one big hole.

The butter fly should be closed correct when it’s idling, when you give it throttle it should open up and let more air in correct?

https://imgur.com/a/5wAMvbb

 

[Ronie]

435 not 345 .

Sorry, wrong saw. I'll see if I have one for the 435

 

[Ronie]

Disregard my post about the carb screws one turn out it's like you set them, I was looking at the wrong saw. I sent you the correct manual in case you need it.

 

[Ronie]

I'll take a look at mine in a few minutes and see how it works.

 

[Ronie]

That screw pushes on a lever that opens the butterfly. It looks like you have yours screwed in way to far. heres a pic of mine from the inside of the carb. You can't even see the white thing or the threads.

 

[Ronie]

Found an old 435 carb. Here's how it works.

 

[kur1j]

Found an old 435 carb. Here's how it works.

Thanks!

It’s fixed! Here is what was going on. No vacuum leak, it just all had to do with what seems to be multiple issues going on with the throttle and not knowing how much to adjust the idle screw.



Running demo.



Is it reasonable to expect it to bog some while it’s still not really hot? The bog seemed to go away after it was nice and warm. But if it sat for 10-15 min in 40 degree weather it would bog.

 

[Ronie]

Glad it's up running! If you do a search on the site you can find a bunch of how to threads on carb adjustments and you can get that carb dialed in just right.

 

[pioneerguy600]

OMG, you mean it wasn`t an air leak around the seals or base gasket, who would have thunk.....LOL

 

[pioneerguy600]

Your throttle rod appears to not have full movement, is it connected correctly to the trigger in the rear handle?

OMG, not an air leak!

 

[kur1j]

OMG, not an air leak!

You were right . Thanks for recommending to revisit it...granted buying a new carb for 15$ would have fixed it too and i wouldn’t have wasted 6 hours dickering with it.

 

[pioneerguy600]

You were right . Thanks for recommending to revisit it...granted buying a new carb for 15$ would have fixed it too and i wouldn’t have wasted 6 hours dickering with it.

Easy enough to overlook, been at this for a very long time, hundreds of saws repaired and still find new things. I seen your throttle was not acting right in your first vid, it was not returning to the idle position. While not knowing your model of saw intimately , not having it in my hands, your short vid not showing the various levers on the side of the carb and going off the short stroke the throttle lever/linkage was making I could discern it was not retreating far enough to come back to idle position. Many saws I have worked over has had a problem with the throttle rod not installed correctly in the trigger of the rear handle, the linkage would allow the carb to open fully but not return to the idle position, Good on you for following through on getting it right and weeding through all the posts in your thread.

 

[m2theb]

Thanks!

It’s fixed! Here is what was going on. No vacuum leak, it just all had to do with what seems to be multiple issues going on with the throttle and not knowing how much to adjust the idle screw.



Running demo.



Is it reasonable to expect it to bog some while it’s still not really hot? The bog seemed to go away after it was nice and warm. But if it sat for 10-15 min in 40 degree weather it would bog.

Easy enough to overlook, been at this for a very long time, hundreds of saws repaired and still find new things. I seen your throttle was not acting right in your first vid, it was not returning to the idle position. While not knowing your model of saw intimately , not having it in my hands, your short vid not showing the various levers on the side of the carb and going off the short stroke the throttle lever/linkage was making I could discern it was not retreating far enough to come back to idle position. Many saws I have worked over has had a problem with the throttle rod not installed correctly in the trigger of the rear handle, the linkage would allow the carb to open fully but not return to the idle position, Good on you for following through on getting it right and weeding through all the posts in your thread.

Thanks for the post.
I’m struggling with similar symptoms as your saw was.
i did a detail strip, fully exploded and rebuilt it. Looking for obvious visual sign or loose screws on the clam shell. Built it back up with the same results. No new parts.
After reading your post I went out to check what was happening.
I think it was similar; the choke plate wasn’t returning 100% when I hit the throttle on start. 90%, but not the whole way.
i hit all the moving parts with lube and it worked better, but not 100%. I wasn’t getting the open “click” all the time.
But if I use the fast idle, pull the red knob out and down, and then put it in choke, the choke plate will go back to 100% on throttle blip.
Haven’t tried to run it yet. Tomorrow
I hope that does it, probably with some tuning since everything is out just trying to get it to run.
if not I’ll pressure and vac check it and chase that.