Thread: Chainsaw non-start problem

First up, saws don't seize without a reason.
Either no oil was mixed with the fuel, an air leak has developed, leaning the saw out and seizing it, it just wasn't tuned right and lean seized from a lack of fuel/oil, or it was left for a long time unused with stale fuel and this or corrosion in the carby has killed it.

Fuel mix should be dumped after six weeks maximum.
Fuel goes off, (aromatics evaporate) mix can separate out of suspensions and E10 fuels absorb moisture.
All can lead to poor running or worse.

Secondly, one ring pistons are used on lots of pro saws, there isn't an issue there.

Start problems on a Husky ?
They are no worse than any other brand. Hard starting is nearly always an operator issue.

In other words your issues lie not with the brand of saw but another mechanical issue.

If you haven't first determined what killed the saw initially, I'd be loathe to run it with a new P&C.



First up I'd be checking the state of the fuel and impulse lines, that saw is a few years old and E10 fuel can degrade older hoses.
Check for splits or cracks, either are death to the piston and cylinder.

Where do you have the jets set at ?
Look in the manual to see what the initial settings are for the HS and LS screws and then you can tune from there.
Actually, stripping the carby and putting a kit through it would be good insurance.
Corrosion from sitting for a long time can block a fuel passage and lean seize a saw.

Have a good look as the carby boot, make sure there are no tears or perforations and make sure the clamp is OK.

An air leak through the crank seals or from the base gasket (which you would've changed) can also lean seize it, but with those low hours I'd doubt it, and you've changed the base gasket with the new cylinder.

Pressure and vacuum testing the cylinder/crankcase is usually done to eliminate leaks here.

This is an excellent animation to see how the carby works.

http://www.dolmar.com/downloads/144/carburetor.exe

Thanks Rick130

Yes...there's always a reason. I can rule out not adding oil. Air leak could be possible. No corrosion in carby at all. It was tuned by the dealer, not long after I got it, as hot restarts were a problem...and they continued to be a problem...maybe that points to something?

It did get E10 fuel quite a bit, before I learned of the potential issues, but the hoses have remained fine.

Bit of a learning issue initially with the cold start, but hot restarts were the main problem. Obviously I have a problem after the P&C replacement. There's something else I need to do, but don't know what.

It's got new fuel in it now & as I saw fires nicely with a few drops in the chamber...so it's not the fuel. The impulse lines are clear and appear to be fine to me.

Is there any valving involved to direct the fuel flow when the diaphragm is pumping?? Needle valve part of it??

Jets are set as recommended. I'd have to check, but from memory I think it was 1 full turn out each. Carby boot was also good, as expected in a low hr machine.

An air leak through the crank seals? Haven't tested. If so, it may have been a problem since new, looking at the history.

Fact is, it was a problem from the start & looking back it probably had started picking up quite early. I remember a number of times I'd pull the cord and it wouldn't shift on the first attempt. Seizing crossed my mind, but because it was so new, I discounted that idea immediately. In retrospect...it probably was picking up in the first few hours of its life. Hence my belief that it was not built right, poor build quality or whatever.

regards
Brid

Originally Posted by Brid

Thanks Rick130

Yes...there's always a reason. I can rule out not adding oil. What oil are you running and what ratio? Air leak could be possible. Probable - as Rick130 says check for kinked pulse hoses, fuel hoses, split hoses. No corrosion in carby at all. It was tuned by the dealer, not long after I got it, as hot restarts were a problem...and they continued to be a problem...maybe that points to something? Probably wrong fuel mix at some stage very early in it's life, or tuning. Did it run well for the first tank of fuel?

It did get E10 fuel quite a bit, before I learned of the potential issues, but the hoses have remained fine.

Bit of a learning issue initially with the cold start, but hot restarts were the main problem. Obviously I have a problem after the P&C replacement. There's something else I need to do, but don't know what.

It's got new fuel in it now & as I saw fires nicely with a few drops in the chamber...so it's not the fuel. It is definitely a fuel problem. If you can poor fuel in the plug hole and it fires you have a fuel problem. The impulse lines are clear and appear to be fine to me.

Is there any valving involved to direct the fuel flow when the diaphragm is pumping?? Needle valve part of it?? One side of the carby is the fuel pump, small diaphragm area activated by the crankcase pulses and two flap valves to allow flow only one way. The needle is part of the metering system and is controlled by the metering diaphragm. If someone has stretched the needle lever spring this can cause a problem as the metering diaphragm cannot over come the closing pressure of the spring. Not likely, but would suggest whoever has been stuffing with the carby doesn't know what they are doing.

Jets are set as recommended. I'd have to check, but from memory I think it was 1 full turn out each. If one turn on each is factory setting 1/8 either way on each is about maximum tuning range. If you have to go further than this there is usually another problem.[/COLOR] Carby boot was also good, as expected in a low hr machine.

An air leak through the crank seals? Haven't tested. If so, it may have been a problem since new, very, very, very unlikely from new, but possible. looking at the history.

Fact is, it was a problem from the start & looking back it probably had started picking up quite early. I remember a number of times I'd pull the cord and it wouldn't shift on the first attempt. Seizing crossed my mind, but because it was so new, I discounted that idea immediately. In retrospect...it probably was picking up in the first few hours of its life. Hence my belief that it was not built right, poor build quality or whatever. very very very unlikely, as Rick130 says - Hard starting is nearly always an operator issue.

In other words your issues lie not with the brand of saw but another mechanical issue.

Operator issues include, incorrect fuel mixture, blunt chains can cause lean running problems and siezure, running lean/tuning, old fuel, E10 will require different tuning to unleaded, elevation, ambient temp, .

regards
Brid

I spent the first twenty years of my working life - and from about 12 years old - running around the bush with chainsaws or working for businesses, or owning businesses that repaired and sold chainsaws and 99% of problems are operator caused and mostly because of lack of knowledge. May sound a bit harsh, but facts usually are and chainsaws are one of the most misunderstood tools the general public can get their hands on. I doubt there would be one in one hundred out there actually maintained and operated efficiently and correctly.

Another Rick

+1 on everything these guys have said.....something to think about, most major brands have a range of quality, ie: Stihl, Husky,Dolmar etc etc etc and not just saws offer pro range right down to homeowner that are alot less quality. A name is only 1 of many things.

I wish more pro saws had 1 ring

Well, I have a Jonsered, which is (almost) identical to your saw (Jonsered and Husqvarna are the same company) and experienced similar problems. It turned out it had overheated and the piston had seized... I needed a new piston and compression rings, and everything is fine again. Mine is a professional saw and had only covered a few hours as yours, but during last winter we had some storm damage in the forest and trees lying everywhere across the road and tracks. Despite heated grip I just wanted to get the job finished and back home again as it was f*****g freezing and blowing, so I pressed the motor hard, which resulted in said damage. I used it only a couple of times for light work after that until it finally refused to start. Luckily the service staff was great and I got it back after only a couple of days (and they gave me a courtesy saw in the meantime).

The Husqvarna brand is basically high quality, especially the European made models. They have some US-assembled models that are of decent quality as well, just somewhat heavier and less well equipped.
Cheers

Originally Posted by Jojo

Well, I have a Jonsered, which is (almost) identical to your saw (Jonsered and Husqvarna are the same company) and experienced similar problems. .................. Mine is a professional saw.................. Cheers

The Husky 345 is no longer listed, im pretty sure the 435 is its replacement, niether are in their pro grade range. home/land owner yes....but not pro range, there is a difference. Either way I wonder how sharp the chains were when these saws are being burnt up