Husky idles up, dies when grab throttle

[tdcarter]

Hi,
I just had pulled my 455 apart last week to replace the drive sprocket with a new Oregon unit, but it must be a cursed. I got the saw back together and fired it up on the bench, all was fine, but I only let it start and idle for a second as I was in the basement.

Out in the field, I start the saw, it idles up and sounds stable, then I grab the throttle and it dies. Not sputters, not hesitates, just flat dies like I hit the kill switch. Re-start, same thing, choke in, choke out, no change in behavior. Saw starts and gets up to fast idle, dies when ya grab the throttle.

Gas is good, used the same gas can for the 35, and it finished up the job for the day.

Some surfing and it seems like maybe the jet might be clogged?
Opinions? Thoughts?

 

[Adirondackstihl]

Low speed circuit too lean :msp_confused:
I'd at least try to richen the "L" jet before I made any terrible assumptions

 

[eriklane]

Can't say I'm an expert, but my 372 just did the same, I think...ran fine low, but when I hit the throttle, it'd bog and die. Or, it'd race after starting but as soon as I put gas on it, dead.

This was after a new ring, base gasket, and, I'd even opened the carb, and a new plug. Re-opened the carb, checked it-all clean, put it back together, ran fine.

Check inside the carb-there's a dish shaped filter/screen. I had a blower once full of crud. Also, take out the air filter-if it runs good with no filter, its filthy...I had a Stihl that did that.

 

[fearofpavement]

Does the saw stop abruptly like it's locking up or is it more like the engine is starving for fuel or shutting off like the ignition is switched off? What all did you disassemble when you changed the clutch drum? Could it be a wrong part? spacer or washer left out or in wrong order? Bearing not installed or wrong size?

 

[Termite]

Can't say I'm an expert, but my 372 just did the same, I think...ran fine low, but when I hit the throttle, it'd bog and die. Or, it'd race after starting but as soon as I put gas on it, dead.

This was after a new ring, base gasket, and, I'd even opened the carb, and a new plug. Re-opened the carb, checked it-all clean, put it back together, ran fine.

Check inside the carb-there's a dish shaped filter/screen. I had a blower once full of crud. Also, take out the air filter-if it runs good with no filter, its filthy...I had a Stihl that did that.

I had the same thing with a customers 41 Husky. I will find it sooner next time.

 

[tdcarter]

Does the saw stop abruptly like it's locking up or is it more like the engine is starving for fuel or shutting off like the ignition is switched off? What all did you disassemble when you changed the clutch drum? Could it be a wrong part? spacer or washer left out or in wrong order? Bearing not installed or wrong size?

Saw just dies like I hit the kill switch. When i swapped clutch drum, just swapped that. Direct replacement, pull chain cover, tap on clutch with hammer/brass rod to break it loose, unscrew, remove drum, install new drum after inspecting bearings, screw on clutch, re-install cover (with bar and chain in place naturally).

Saw does not even appear to want to idle at low. The only start I get is if I pull and reset choke. Is this what activates the fast idle?

Once I choke it, it will fire up and run a fast idle, I can then push in reset choke, it keeps running, chain turning as the engine rpm builds.

Then I grab the throttle and no matter if I just blip the throttle, to kick it from fast idle to low idle, or grab it and go full-on WOT, engine instantly dies. No sputtering or attempting to run, just dies like I hit the kill switch or cut off the fuel.

 

[tdcarter]

Can't say I'm an expert, but my 372 just did the same, I think...ran fine low, but when I hit the throttle, it'd bog and die. Or, it'd race after starting but as soon as I put gas on it, dead.

This was after a new ring, base gasket, and, I'd even opened the carb, and a new plug. Re-opened the carb, checked it-all clean, put it back together, ran fine.

Check inside the carb-there's a dish shaped filter/screen. I had a blower once full of crud. Also, take out the air filter-if it runs good with no filter, its filthy...I had a Stihl that did that.

Well I will double check the air filter tonight, but I just checked it not too long ago and it was fine. Seems kind of strange that if it can run fine on fast idle, why not WOT.

I'm hesitant to adjust any carb settings just yet. If I understand correct there is a separate jet for the starting run? I can't get it to idle low, only idle is if I choke it and then unchoke, never touching the throttle.

Previously this was my reliable guaranteed-to-go saw. I kind of miss not having it there.

 

[SawTroll]

Sounds like a fuel system or carb issue to me, but it could also be a very lean "L" setting.

Anyway, there isn't much you need to "pull apart" to change the sprocket (you just need to take the clutch off), so I doubt that has anything to do with the issue....

 

[nmurph]

It sounds like you have an air leak. Was the saw running OK bf you disassembled it? Changing the clutch drum should have zero effect on any of the potential areas that would give you the symptoms your discribe.

I would eliminate the easy stuff first. If you haven't already done so, I would remove the limiter caps from the H&L needles. Then set both 2.5 turns from lightly seated.

If that doesn't fix it, I would next check the impulse line that feeds from the cylinder to the flange which the carb attaches to just ahead of the cylinder. Make sure it is seated well at both the cylinder and the flange. Also, check it for leaks.

If the problem still exist, I would diassemble the carb and spray it out good with carb cleaner. Do not use compressed air. If the carb hasn't been rebuilt in the last couple of years, I would get a carb kit from the dealer (~$15) and install it.

If you still have the problems, either the crank seals or the base gasket seals are leaking. That requires disassembling the saw. It isn't as hard as it sounds and is a great learning experience.

 

[SawTroll]

Just a (stupid?) thought - are you sure the chain brake isn't in the "on" position? :msp_w00t:

 

[nmurph]

Just a (stupid?) thought - are you sure the chain brake isn't in the "on" position? :msp_w00t:

Brilliant!!

 

[tdcarter]

Sounds like a fuel system or carb issue to me, but it could also be a very lean "L" setting.

Anyway, there isn't much you need to "pull apart" to change the sprocket (you just need to take the clutch off), so I doubt that has anything to do with the issue....

yeah... I don't the new drum/sprocket is hexed, just weird it started then. I wonder if I knocked something loose when I had it on it's side on the bench? I would think that a saw horizontal in the filed on a felling cut or plunging would vibrate the engine / tank and carb just as much as me tapping on the clutch with a hammer and a brass rod.

It sounds like you have an air leak. Was the saw running OK bf you disassembled it? Changing the clutch drum should have zero effect on any of the potential areas that would give you the symptoms your discribe.

I would eliminate the easy stuff first. If you haven't already done so, I would remove the limiter caps from the H&L needles. Then set both 2.5 turns from lightly seated.
....
If you still have the problems, either the crank seals or the base gasket seals are leaking. That requires disassembling the saw. It isn't as hard as it sounds and is a great learning experience.

Hmm.. don't mind learning, just wrong season to do it in. Saw was previously running great, carb adjustment tool has not been used in a long time, 2+ years for sure.

 

[tdcarter]

Just a (stupid?) thought - are you sure the chain brake isn't in the "on" position? :msp_w00t:

Well, chain spins when saw idles up after starting, but then engine and chain both come to a stop when I grab throttle. Maybe I put the drum/clutch on backwards and the chain brake is now grabbing the crankshaft? :msp_tongue:

 

[SawTroll]

yeah... I don't the new drum/sprocket is hexed, just weird it started then. I wonder if I knocked something loose when I had it on it's side on the bench? I would think that a saw horizontal in the filed on a felling cut or plunging would vibrate the engine / tank and carb just as much as me tapping on the clutch with a hammer and a brass rod.
..... .

That shouldn't upset anything by itself. If all is normal in the clutch and brake area, you should be able to easily pull the chain around the bar by gripping the chain with two fingers, when the saw is not running.

 

[tdcarter]

you should be able to easily pull the chain around the bar by gripping the chain with two fingers, when the saw is not running.

Yep, can easily do that.. as I pull on the chain to set the bar adjustment/chain tension after replacing the clutch. So I knwo the brake is not grabbing.

Never tried it with the saw running.. but I did lay fingers across a hot muffler once... only once.:msp_scared:

 

[SawTroll]

Yep, can easily do that.. as I pull on the chain to set the bar adjustment/chain tension after replacing the clutch. So I knwo the brake is not grabbing.

No issue there then!

Never tried it with the saw running.. but I did lay fingers across a hot muffler once... only once.:msp_scared:

Don't, if you want to keep your fingers! :msp_biggrin:

 

[phillipmc]

maybe this is a stupid thought. But when you where tapping on the clutch to remove it to replace the drum, maybe you sheared the flywheel key ?

 

[biggus]

Maybe I'm blind but I didn't see where you addressed the two posters who recommended adjusting the 'L' screw on your carb. I wouldn't even consider doing anything else until you've done that and clean up the carburetor; replacing the consumable items in there as necessary.

 

[SawTroll]

Maybe I'm blind but I didn't see where you addressed the two posters who recommended adjusting the 'L' screw on your carb. I wouldn't even consider doing anything else until you've done that and clean up the carburetor; replacing the consumable items in there as necessary.

I would start with the "L" as well, then fuel filter, fuel lines, impulse, intake and carb.....

 

[tdcarter]

Nope, have not tried the 'L' adjustment, haven't been home yet. I work on an AFB and they get a little weird if I bring a saw in and set it on my desk and try to start it... like it's a WMD or something.

Will try the 'L', just looking for all possibilities before I make things worse then they are. Just strange that it happened so quickly and the fact it absolutely will not even try to run unless I pop the choke on/off.