Chainsaw cuts out under load

[Apprentice_GM]

G'day All,

I have a Husky 455 Rancher about 4 year old but not used that much (maybe 25 cords of felling & bucking?) in pretty good condition. Yesterday I did about 45 minutes of cutting, saw warned me it was low on fuel as per normal (it kind of drops from high revs and sounds like it is struggling for fuel when the tank is empty - no kidding hey!) and then went to do a second tank after a rest. It took a few more pulls than normal to start, but started and idled fine, then cut out when revving up. This continued - whenever I rev'ed up for cutting it would initially start to rev then drop back down and either sound like it was going to cut out, or actually cut out - exactly as it does at the end of a tank.

So, I thought bad fuel? But the 2nd tank came from the same jerry can as the first tank, albeit the last "dregs". The jerry can is "clean" ie no visible contaminant. I pulled out the fuel filter and it looks pretty clean / good, no blockage. The air filter also looks fine, it's original, but pretty clean. I figure spark is fine as it starts OK and can idle for ages no problem and can even rev up for a very short time (a few seconds). A friend suggested I ensure the air entry to the fuel tank isn't blocked - he thought there would be a pin-hole intake with a flap - but the fuel tank cap doesn't appear to have anything like that, it appears fully sealed (which begs the question, how does air get into the fuel tank?) so I don't know where to go to clean the fuel tank air intake.

Another friend suggested it could be water in the water carbie and clean that - but I don't know how to do that (I'll check out youtube now and see if the manual tells me how) - would that give the symptoms I have do you think?

I think it could still be a fuel line blockage as that fits the symptoms in my limited experience and knowledge, but I don't know how to check and clear the fuel line.

Any thoughts or suggestions of what I should do? There are a couple of shops that could help, but one is run by total morons, and the other is so busy they can't look at it for a while and charge pretty hefty prices for service anyway (this would be a $200 job). Any advice gratefully appreciated.

Hope you are all enjoying a warm Christmas, whether you are a Southern Hemispherer like me getting it from Nature or a Northerner surrounded by snow but with a warm fire heating you through

 

[dougand3]

The inside of carb will have a fine mesh screen, through which fuel flows. Screen could have debris and varnish on it. Getting to it requires carb dis-assembly and then adjustment of Hi, Lo and Idle screws. The fuel line: is it real hard feeling? - could have a crack. You follow it from the fuel filter in the tank, out the hole to the carb. Could be partial clog of fuel filter, too. Good to replace fuel line if they are old and hard. In the states, Oreilly's Auto is a good deal for tygon fuel line - $2.29 for 2 feet. Youtube has good "how to" videos. Check out donyboy73 - he does good ones.

 

[UncleJoe]

Good to replace fuel line if they are old and hard..

...or old and SOFT. Some years back I had a problem with a saw cutting out under load. Checked all the usual problem areas. Filters were clean, no leaks in lines etc. Turns out the line from the tank to the carb was so soft it was collapsing when there was a higher demand for fuel. Put in a new line - problem solved.

 

[Adios Pantalones]

Fuel filter, and air inlet filter for the tank are good places to start. If the air inlet gets clogged, it can cause a vacuum that keeps fuel from flowing- this gets worse when it needs to suck fuel faster.

 

[MDFisherman]

I'm gonna take a shot in the dark and say the high speed jet is clogged? You can try twisting the screw in and out and see if that helps. Just count how many turns you moved it so you can turn it back to the stock setting.

 

[kenskip1]

How about the diaphragm or fuel pump is week.It does not have enough flex to draw the gas into the carburetor.Possibly an impulse leak..Check for cracks in the gas lines, Ken

 

[Apprentice_GM]

Update - I replaced the spark plug, fuel filter and drained all fuel, replacing with newly petrol freshly mixed with synthetic oil @ 50:1. I noticed the priming pump / bubble had a hole in it, so I replaced it as well.

Took a few minutes of idling before I could rev it high and not have it cut out. I could then do some cutting. I have had a couple of cutouts since, but not as bad as before all this happened. Thanks for all your advice - it sounds like I should rebuild the carbie / replace diaphragms / adjust the idle & high speed jets / screws if the problem persists. I have a mate who can help me with that. Given that I can now do 30 minutes of cutting without cutout (most of the time) it sounds like the fuel line is OK, but I understand how that could be a culprit in similar situations.

On another note, ever since I got this Husky it has leaked chain lube oil. It doesn't appear as though the opening is too big / setting too wide / flow too high, as when cutting it does less than half a tank of lube oil per tank of fuel. However in a week or 2 sitting in my garden shed it can leak the whole lube oil reservoir everywhere. I noticed in a youtube video of another Husky model that a guy fixed a similar leak, basically sealing the tube or line coming from the lube oil reservoir to the little applicator. It was a fair bit of effort to get to and seal, but if that's the cause of my leak, worth having a go or paying someone. Can anyone advise on whether all saws, or at least most Huskies, operate in a similar way and therefore this fix might work for me? I used to have a Husky 353 and it was an awesome saw, never leaked, lighter, more powerful and less vibration than the Rancher 455, but the 353 was a long term loaner since returned to owner.

Thanks again all for any advice.

 

[NH_Wood]

Glad it's getting better! As for the oil leak, does it do the same in all conditions - different temperatures, etc.? Empty the oil from the saw, remove the clutch, oil pump cover, and clean the entire area from the oiler through the pick up line. Once you reassemble the oiler mechanism, fill the oil tank and try to see if you can tell where the oil is coming from - better on a hot day when the oil is thinner. You can place some cardboard under the saw to also have some idea where the leak is coming from, but you'll have to check it often before a big pool forms). Here's a vid on fixing a similar problem on a 350/346xp, but your oiler mechanism is different - might give you an idea though. I think he's even from Australia! Cheers!

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[Apprentice_GM]

Haha, that's the video I saw! I was wondering if that model 346 & my Rancher 455 had the same or a similar enough oiling system, so that repair would work for me?

Sounds like it's worth proceeding as if it does.

He's actually from England, not Oz, but all good, I can understand him clearly lol!

Thanks for the advice!

 

[pen]

My 350 leaked oil from day 1. After one time of puking oil all over a shelf in my garage, I didn't need the saw for a week or so,,, in to the shop it went under warranty. I came back a week later and the shop owner asked if he wrote the repair ticket up wrong??? I told him it was leaking oil like a sieve just sitting, he pointed to where the saw sat for a week in his shop on the floor and said look at the cardboard underneath, anything there? (Answer was no )

Took the saw home, set it back on the shelf, came back 2 days later, puked oil all over,,,,,,,, used the saw, sat for a few more days, went back to the shop, same thing again..... Long story short, this went on for about 6 months (puked whatever oil it had in it all over my shelf but was fine in the repair shop) until a buddy of mine bought a brand new 357xp and it puked it's guts worth of oil all over the inside of his utility box in the back of his truck. After he told me that, I told him my story and I asked him where he had his truck parked? It dawned on me that his saw puked after a cold night, then he parked the truck in the sun....

At the shop, my saw was sitting on a concrete floor which helped maintain the temp / no quick temp changes and it didn't puke oil. When I brought it home, I was putting it on a metal shelf in an uninsulated garage that may have dropped to 40 at night, then 85 or 90 when the sun beat down on it in the afternoon, hence why it puked the oil out.

I have since moved the saw (and it's new brother) to a home on the concrete floor in the garage where the temp doesn't swing as much and I almost never find oil under the saw, and certainly not a whole tank getting pushed out like I did previously.

Not saying this is your problem, but it's what I have found with 3 now. I haven't checked that video out for the fix that NH_Wood posted, but that might solve my problem for leaking with big temp changes.

As to the cutting out under load, I had this with a weed wacker last year and it turned out being a fuel line that was apparently warming up and sucking some air in at a nipple. It was tight when cold, but must have loosened just enough when warm that it was giving me intermittent issues. In that case, I found it by simply trimming a bit from each end of the fuel hoses where it slipped over (if there were still going to be long enough to fit) and found that it solved my problem.

 

[NH_Wood]

Haha, that's the video I saw! I was wondering if that model 346 & my Rancher 455 had the same or a similar enough oiling system, so that repair would work for me?

Sounds like it's worth proceeding as if it does.

He's actually from England, not Oz, but all good, I can understand him clearly lol!

Thanks for the advice!

No worries and I guess I need to work on my accents more! Your oiler mechanism is different, but perhaps there is some way to use the technique with your saw - I'd have to look at a 455 oiler again, but it's not the same. Cheers!

 

[Smoke Stack]

G'day All,

I have a Husky 455 Rancher about 4 year old but not used that much (maybe 25 cords of felling & bucking?) in pretty good condition. Yesterday I did about 45 minutes of cutting, saw warned me it was low on fuel as per normal (it kind of drops from high revs and sounds like it is struggling for fuel when the tank is empty - no kidding hey!) and then went to do a second tank after a rest. It took a few more pulls than normal to start, but started and idled fine, then cut out when revving up. This continued - whenever I rev'ed up for cutting it would initially start to rev then drop back down and either sound like it was going to cut out, or actually cut out - exactly as it does at the end of a tank.

So, I thought bad fuel? But the 2nd tank came from the same jerry can as the first tank, albeit the last "dregs". The jerry can is "clean" ie no visible contaminant. I pulled out the fuel filter and it looks pretty clean / good, no blockage. The air filter also looks fine, it's original, but pretty clean. I figure spark is fine as it starts OK and can idle for ages no problem and can even rev up for a very short time (a few seconds). A friend suggested I ensure the air entry to the fuel tank isn't blocked - he thought there would be a pin-hole intake with a flap - but the fuel tank cap doesn't appear to have anything like that, it appears fully sealed (which begs the question, how does air get into the fuel tank?) so I don't know where to go to clean the fuel tank air intake.

Another friend suggested it could be water in the water carbie and clean that - but I don't know how to do that (I'll check out youtube now and see if the manual tells me how) - would that give the symptoms I have do you think?

I think it could still be a fuel line blockage as that fits the symptoms in my limited experience and knowledge, but I don't know how to check and clear the fuel line.

Any thoughts or suggestions of what I should do? There are a couple of shops that could help, but one is run by total morons, and the other is so busy they can't look at it for a while and charge pretty hefty prices for service anyway (this would be a $200 job). Any advice gratefully appreciated.

Hope you are all enjoying a warm Christmas, whether you are a Southern Hemispherer like me getting it from Nature or a Northerner surrounded by snow but with a warm fire heating you through

Apprentice_GM, try cracking the fuel cap open when it starts to bog down. If it clears it up it most likely the fuel tank breather tube or element. It seems that you don't have one in the fuel cap, like you said. Look for a hose that goes from the fuel tank to the threads of a screw or something. Like Adios said above, if this tube is blocked it will not allow the fuel to flow. Worth a shot before you begin breaking it all down.

Good luck!