Husky 55 stops reving

[Anthony Grice]

Have a husky 55 that I just rebuilt w/ am piston and cylinder. Impulse seal and intake boot are new, carb has a kit in it and new fuel lines. The saw starts and idles just fine. Evens revs well for about 2 minutes then begins to lean out and races a bit at idle. Naturally I'm thinking tank vent. So I lay it over and pop the gas cap and it settled right down and reved fine. So I replaced the tank vent on the clutch side, but the problem remains. The tank vent from husky was a black tube with a small asprin sized vent. Is that asprin looking piece one way such that it can only work in one direction? It appeared to be all one material so it didn't appear to be one way when I installed it in the black vent tube but it looks like a brand new part would've solved my problem. The saw is clearly fuel starved after creating a vacuum in the fuel tank?

Any advice on this would be appreciated.

 

[cus_deluxe]

Yep replace that porous stone vent.

 

[Agrarian]

Yes, as cus_deluxe said, it is just a porous material. The tank need to vent pressure when it is heating up and relieve vacuum when it is cooling down or running.

 

[Onan18]

I have put brand new Husqvarna vents in and they either leaked or would not vent. What I have started doing is using a piece of fuel line with an Echo tank vent, works every time. on the 55's when you remove the little cover to access the vent there is a channel molded into the tank. I route the line through that channel, loosen the front handle screws, tuck the vent in behind the handle, and tighten the screws back down. Nice and clean.

Joe

 

[sunfish]

Yes, as cus_deluxe said, it is just a porous material. The tank need to vent pressure when it is heating up and relieve vacuum when it is cooling down or running.

Yep replace that porous stone vent.

He said he replace the vent and still has the problem?

 

[Onan18]

He said he replace the vent and still has the problem?

Yes sir and I have had brand new Husky vents be defective, actually several lately. That is why I started using a piece of fuel line and an Echo vent. I would probably go ahead and replace the manifold though, the pulse pipeswhen they get old can sometimes seal when cold, but not when at operating temperature. Plus they are cheap.

Joe

 

[Anthony Grice]

The intake boot and the small impulse pipe seal have already been replaced..

I will give the echo fuel vent a shot.. it's been a project saw for me to learn on so a few bucks to make it a success is easy money to spend in my book..

Thanks for the help gents.

 

[Anthony Grice]

Yes sir and I have had brand new Husky vents be defective, actually several lately. That is why I started using a piece of fuel line and an Echo vent. I would probably go ahead and replace the manifold though, the pulse pipeswhen they get old can sometimes seal when cold, but not when at operating temperature. Plus they are cheap.

Joe

Also, Joe, if you have a moment to snap a photo of where you ran the vent, just from the outside that would be great, it sound to me like you running out of the factory channel where the vent goes then basically looping back in between the tank/handle and the cases?

Is that accurate?

 

[Onan18]

I will have to dig through the pile and see if I can come up with a 55 chassis to use, this was on customers saws. As I said before for no more than they cost you should probably go ahead and replace the manifold ( the plastic piece that the carb mounts to) also. The holes that the screws that mount the carb thread into can sometimes get partially stripped, especially if the carb has been off several times, and will feel like it has tightened down but not be tight enough to provide a good deal.

Joe

 

[Anthony Grice]

Oh oh oh, I gotcha, was misunderstanding what you meant by manifold. yes I agree I was worried about thay myself recently but when I was working on this saw just the other day it tightened up nicely. I will source another though because I do agree, for what they cost it can't hurt.

 

[PogoInTheWoods]

Double check the impulse 'pipe' for a correct fit between the cylinder and the tube from the intake assembly. Incorrect fitment resulting in a kink or pinch is not uncommon when re-assembling these things. On the other hand, bad tank vents are.., .at least in my experience with 55 rebuilds...and I've done quite a few.

Also double check the intake boot for a small crack or tear. There were some bad ones recently that just flat out split after minimal use according to a warning from my area Husky dealer mechanic when I stopped in to pick up a couple a few weeks ago.

 

[PogoInTheWoods]

Just as a matter of record in this particular thread (and recommended troubleshooting practice) to determine if the tank vent is the actual problem...​

BTW, they either work, or they're clogged. Nothing mechanical about em to actually "go bad". And if there's a "plug" on the handle/tank covering the actual vent access to the atmosphere, that is probably the problem right there. Shouldn't be one



But if ya wanna ditch the stock vent in favor of rollin' yer own, just use a piece o' Tygon and a grub screw.

​

 

[neely]

i'v wrapped that plastic carb maniflold with teflon tape set carb back on tighten good to go starts sucking gas you can ck by spraying wd40 around carb base with machine running will start running better when 40 is sucked in or smokes alittle that shows a leak at carb manifold

 

[PogoInTheWoods]

So would a vac/pressure test..., which would also determine the integrity of the seals, case, impulse tube, the whole nine yards.

 

[neely]

true good point

 

[decableguy2000]

Sounds like time to pressure and vacuum test to me. Why did you need to rebuild in the first place? Did you P&V test before the rebuild?

Jeremy

 

[HusqyStihl]

+1 on the Echo tank vent, i've also had problems with multiple new and used husqy vents on my 51/55 conversion and i'll be taking this route once im through with customers saws

 

[Anthony Grice]

Sorry to resurrect an old thread but I still cant get this things to run exactly right. I tried the echo vent which worked OK sometimes then other times it acted the same. It sat on the shelf for awhile as I dealt with my frustration. I pulled it back out at one point and epoxied two nuts on the back of the intake manifold so that I could get a good tight seal with machine screws. That worked like a champ for those who have these saws. If I run across another one I will be doing this first thing.

I never vac/pressure tested it before rebuilding as I was told it was straight gased. So I took it to a buddy and had him do it now and everything checked out. SOOOOOO I bought another husky tank vent. Now rather than it sometimes working and sometimes not. It never runs right. In one of the photos above it appears that the porous stone material protrudes from the plastic "straw" if you will. Mine is pressed in much further, pretty much flush with the top of the vent tube. Would this cause the failure?

 

[Agrarian]

No, the positioning of the white porous thingy makes no difference to its operation.

Did you replace the fuel filter?
Is it possible the carb kit was not installed correctly? Could you have set the metering lever too low? Which carb do you have?

 

[Anthony Grice]

I suppose that is certainly a possibility. I will take a look when I get home on the carb model. If it where the carb would opening the fuel cap make a difference.. when I lean it over and just Crack it the thing runs like a scalded dog for as long as I am brave enough to hold the trigger..