Husky 55 bogs out and stalls when on throttle

[StihlaHuskyFeller]

Hi everyone, new user here. I'm having a problem with my Dad's 55 saw; I believe it is a 2001 m/y. It will start fine just like usual, and it will also idle fine like normal. As soon as I hit the throttle it will bog down and stall. It will start to rev up just a little bit and stall out. No amount of working the throttle or feathering it will get it to rev up. Each time it stalls, it will fire right back up and idle fine, but that's it.

So far I have changed the fuel line thinking it was the problem, no dice. Old fuel line was thin in a few places but not cracked. I have the air filter off, carb off, and the rest of the plastic intake pieces all the way to the cylinder. I read about the little yellow impulse pipe being a problem, but it looks ok from what I can see. It is still in the cylinder, so it wasn't a real inspection of it. I think i will replace it anyway, as I'm this far already. The black intake boot looks good, no visible cracks and still pliable. The plastic tube the impulse pipe connects to also looks good, no cracks in it that I can see. I'm thinking something in the carb (Zama) must be damaged, as it seemed to happen all of a sudden vs a slow problem over time. Looking through the intake the piston has minimal wear, and lots of life left. This saw sat for a while because nobody wanted to deal with it, and part of me was hoping a new fuel line and fresh mix would cure it but not so much lol. This is the first time this saw has had any work done.

Thanks to covid I can't get a new carb from my Husky dealer until the middle of March sometime. I also can't get one online at SawpartsCanada, and some of the stuff I was hoping to order from them is now out of stock for this saw. I'm thinking of dropping the carb off to get rebuilt, and changing the impulse pipe in the mean time. Is there anything I am overlooking on this saw?

 

[RED-85-Z51]

Sounds like the main jet in the carb isnt feeding any fuel. A few times ive had luck backing the H needle out all the way then put it back in and see if it improves.

Sent from my LM-G820 using Tapatalk

 

[Ozhoo]

Did you check the grommet that the impulse nipple plugs into? Often dried out and crumbly on older saws.

If that checks out, check the spark arrestor in the muffler and then overhaul the carb.

 

[KASH]

I have ran thousands of pieces of equipment in my life and have never bought a new carb unless a part was broken off.It sounds like not getting enough gas threw the hi speed circuit take out the needles and make sure the passages are clear.When you were trying the saw what effect did opening the high speed needle have.Check your intake fuel filter and impulse hose and fuel lines.
Kash

 

[Bob Hedgecutter]

Put some earmuffs on, take the muffler off and see if the saw will throttle up.
Because if it is not a fuel delivery problem, it could well be gas escape problems with a blocked spark arrestor screen...... or a worn out coil.

 

[StihlaHuskyFeller]

Thank you guys very much for the suggestions, I completely forgot about the spark arrestor and muffler. Today I ordered a new impulse pipe, it's supposed to be here in a week or so. I'll replace that as I've got the saw taken apart already, and then I will take the muffler off n giver a go. If not, I'll fiddle with the carb and see what happens. Process of elimination. I'll update after I get the pipe changed, hopefully it arrives on time. I don't think my local dealer stocks any parts other than bars and chains, one little impulse pipe doesn't take up that much room on the shelf lol

 

[StihlaHuskyFeller]

Hey guys I'm back with results. Parts were delayed, and when they arrived the parts gal ordered the wrong intake gasket. Took another week for it to come in, but I used the old one in the meantime to try and get some progress made. I replaced the little yellow impulse grommet, he was worn but still sealed. Intake boot looked good, the plastic impulse pipe from the plastic block was clean and free of debris. I lubed it up and had a bit of a fight to get it into the new impulse grommet, but it worked. Now with the two screws that hold the plastic block to the impulse pipe and intake boot, the right one was hard to remove when I pulled it apart a couple weeks ago. Upon reinstalling, it appears the threads in the case are damaged. I got everything tight because I think we're cutting new threads; either way its back together. It only took 14 pulls from a bone dry tank to prime and fire, but is still doing the same thing. I got it to rev up WOT about three times, then it bogs out and stalls. It doesn't want to idle as good as before, and is getting harder to restart. Seems when I did hit WOT it really screams. I'm gonna find out which carb kit I need and order one, and we'll see what happens. I should have ordered one earlier so I don't have to wait a week lol

 

[irhunter]

I agree: time for a carb kit.

Do you know about turning self-taping screws counter-clockwise until they "drop," and, then clockwise? It is an attempt to avoid tapping new threads in plastic.

Roy

 

[J D]

I agree, time for a carb kit.
If you're unsure of the process you should be able to download the manufacturers instructions or find details in the saws service manual. There are a bunch of good videos online too.
If you're not confident I would just start by removing the H & L screws (turn them all the way in till they lightly seat first & note how many turns out each was at). Once removed poke the straw of a can of carb cleaner in em & give each a blast. Put the screws back in & set them back to where they were. They should be around 1 to 1.5 turns out, any major deviation from that means something wasn't set right in the first place so check manual for what their initial setting should be & set them to that. If that improves things see if you can tune the saw.
Another member previously posted they've had several successes just soaking a carb in fresh fuel for a few days, possibly a cheap & simple/ low risk option to try

 

[chuck shelly]

I agree, time for a carb kit.
If you're unsure of the process you should be able to download the manufacturers instructions or find details in the saws service manual. There are a bunch of good videos online too.
If you're not confident I would just start by removing the H & L screws (turn them all the way in till they lightly seat first & note how many turns out each was at). Once removed poke the straw of a can of carb cleaner in em & give each a blast. Put the screws back in & set them back to where they were. They should be around 1 to 1.5 turns out, any major deviation from that means something wasn't set right in the first place so check manual for what their initial setting should be & set them to that. If that improves things see if you can tune the saw.
Another member previously posted they've had several successes just soaking a carb in fresh fuel for a few days, possibly a cheap & simple/ low risk option to try

hi, I also have had the spark arrestor screen pluged up too. the carb is pretty easy to clean and rebuild. check the screen. good luck, chuck

 

[StihlaHuskyFeller]

Thank you guys very much for the replies. The top of the carb looks wet and reeks of fuel, so something must have failed in it. I figured out which kit I need thanks to the photos on Sawparts Canada (RB-45). I will order the kit on Monday, maybe two kits in case I eff up. Thanks JD, I'll look online for a service manual before I try my hand at rebuilding, but I'm going to have to learn sooner or later. Thank you Chuck, I will check the arrestor as well. Irhunter I did exactly that for the two screws that go into the plastic, but the one that has damaged threads is the short screw on the right side that goes down into the case. It was really tight coming out, which makes me think it was like that from the factory. I didn't notice the threads upon removal, I just noticed now upon install. This saw has never been worked on until now, so that screw was never loosened until I did it a few weeks ago when I started this project. Weird, but I got it tightened down so nothing moves so hopefully we should be okay.

 

[SteveSr]

Thank you guys very much for the replies. The top of the carb looks wet and reeks of fuel, so something must have failed in it. I figured out which kit I need thanks to the photos on Sawparts Canada (RB-45). I will order the kit on Monday, maybe two kits in case I eff up. Thanks JD, I'll look online for a service manual before I try my hand at rebuilding, but I'm going to have to learn sooner or later. Thank you Chuck, I will check the arrestor as well. Irhunter I did exactly that for the two screws that go into the plastic, but the one that has damaged threads is the short screw on the right side that goes down into the case. It was really tight coming out, which makes me think it was like that from the factory. I didn't notice the threads upon removal, I just noticed now upon install. This saw has never been worked on until now, so that screw was never loosened until I did it a few weeks ago when I started this project. Weird, but I got it tightened down so nothing moves so hopefully we should be okay.

RB-45? That is a Zama carb? Classic symptom of a failed main nozzle check valve that is intermittent/stuck closed. Unfortunately this part is NOT included in the kit. There are more threads on this forum... Search "main nozzle"

 

[StihlaHuskyFeller]

Yep Zama EL7 carb. From searching around here it seems that might be my problem, a failed main nozzle. I've been phoning around trying to get a replacement carb but it has to come straight from Sweden, nobody has any stock. It would be the middle of May all going well by the time it gets here. It also seems like this carb is an odd ball for some reason, as everybody is calling for a Walbro WT-170-1. Sawparts Canada lists one but its out of stock. If I can't find a Zama, would a Walbro work in it's place? I thought I'd have this project wrapped up like a month ago lol. I'd much sooner have the Zama, but I'll take what I can get providing it works.

 

[chuck shelly]

Yep Zama EL7 carb. From searching around here it seems that might be my problem, a failed main nozzle. I've been phoning around trying to get a replacement carb but it has to come straight from Sweden, nobody has any stock. It would be the middle of May all going well by the time it gets here. It also seems like this carb is an odd ball for some reason, as everybody is calling for a Walbro WT-170-1. Sawparts Canada lists one but its out of stock. If I can't find a Zama, would a Walbro work in it's place? I thought I'd have this project wrapped up like a month ago lol. I'd much sooner have the Zama, but I'll take what I can get providing it works.

hi I have 2 50,51,55 saws. the 51 has the zama el7 carb and the 50 special has the walbro wt 170. I believe they interchange. good luck, chuck

 

[StihlaHuskyFeller]

Thanks Chuck, I don't see why they wouldn't, but Husky used three different carbs on these saws for whatever reason. I guess it's only a problem due to the virus, I should have been on this project earlier. The info says the walbro doesn't fit the 50 model, but fits 51 and 55 rancher; so it should fit my straight 55. I emailed sawparts to see when they would get stock, but probly no response until Monday. I'll update when I make some progress.

 

[chuck shelly]

Thanks Chuck, I don't see why they wouldn't, but Husky used three different carbs on these saws for whatever reason. I guess it's only a problem due to the virus, I should have been on this project earlier. The info says the walbro doesn't fit the 50 model, but fits 51 and 55 rancher; so it should fit my straight 55. I emailed sawparts to see when they would get stock, but probly no response until Monday. I'll update when I make some progress.

hi, yes even the 50 special used a different choke system as you say. so when I rebuilt it I used a later wt 170 with the later choke system. it will fit your 55 just fine. have fun, chuck

 

[KASH]

I used a Zama with regular choke from a 51on my 50 Rancher.
Kash

 

[StihlaHuskyFeller]

Hey guys I'm back with an update. I ended up ordering the aftermarket Walbro from Sawparts Canada and it seems to have solved the issue. It needs to be fine tuned, but I might take it in to my local dealer next time I'm in town. I'm worried I'm going to have something set too lean or rev to high. Being that it's not my saw, I'm hesitant to play with it and guess lol. Thank you guys very much for all your help and information, I'm looking forward to using this saw for awhile before giving it back to Dad