husqvarna 51

10 years ago

Hi
I bought a husqvarna 51 back in 1994. I have been using it occasionally ever since, maybe a week every year for our own small log burner. Its been a good machine and I hate to throw things away. Over period of time it started being difficult to start, until it stopped all together. I checked the fuel filter, checked the plug and it was fine. A relative of mine with a little experience suggested a new carb might do the trick. Thats when I did a silly thing, I thought that I should put some fuel in the cylinder and see if it will start then!! Whoops I obviously put to much fuel in the cylinder because it went like a bomb and jammed. On removal of the muffler it looked like the ring was no longer in place and there was bad scouring marks on the piston. So I had killed it, but of course the original failure could also have been due to bad compression!! Anyway I decided to fork out 43 quid or so for a new piston and head. I will follow a brilliant you-tube video to help me replace it. I think that it will be a fun challenge and I feel very confident about doing this.

What worries me a bit is that when I have replaced the piston etc and try and fire the machine up again.
1. It may still not start, which may well still point at the carb needing to be cleaned or replaced? Would you replace the card or try and clean it out...I dont feel overly confident about taking the carb apart?
2. If it does start, is it possible that the carb might end up damaging the cylinder again because of a wrong fuel mixture (unfortunately I have probably played around with the settings a little when it first started having problems)? Should I stop it straight away and get the carb adjusted by somebody who knows how to do this...or do you think that I could do this myself (I have not got a tacho-meter to check the speed etc)? I'm not sure how critical the carb settings might be? Can they damage the machine over a short period?

I had to buy a new husky recently to cut a tree down in our back garden. To be quite honest I actually preferred my older one when it was working, so I would love to get it up and running again.

Any comments welcome; Thanks.

Sort by:Oldest

Comments (3)

rcmoser
10 years ago
I dough the pouring to much raw gas in the combustion chamber through the spark plug hole had nothing to do with it other than hydro locking up the piston. If you ran the saw with no mix for more than few seconds or minute then it may of over heated from lack of lubrication in the cylinders and cause the scoring at previous time. Basically you have fuel problem and probably wear problem from years of us. If you have never cleaned the carb since 94, it probably well over due cleaning and rebuild kit,

As for the replacement of the piston if the piston to bore clearance is within spec. the rings gap are within spec. and it easily move up and down with the plug out and builds compression within spec. I say it doing it job of going up and down and building compression. Now all you need it proper amount of fuel mist and correct timing of ignition.

If you want to prime the saw (which is what you attempted by pouring raw gas down the spark plug hole) please us Carb. cleaner in the spray can. The saw will fire off the carb. cleaner, you can control the amount going in the combustion chamber and it evaporates quicker than raw gas , and it does have some lubricating properties. IMO won't hurt as long as you don't run if over few seconds which is all it takes to start sucking mix through the carb. if it's not plugged up and not letting fuel reach the combustion chamber.
philp1863
Original Author
10 years ago
Thank you rcmoser for your kind reply.
The ring is definitely gone, so I have bought a new piston and head which I hope to install next week. I will put it back together and give it a quick go and if that does not work look at getting a rebuild kit for the carb. I wish that I could get hold of a online video for the carb WALBRO WT 170 as good as the piston and head video. However the manual I have got seems quite good.

By the way when I put the fuel in, the chain saw ran for about 5 seconds if that...but it was running very fast and that in my inexperienced opinion broke the ring. Maybe it was on the way out anyway??? I will look into getting a re-build kit for the carb.

Thanks again
Related Discussions
chainsaw
Q
Comments (1)
On a Rancher 55 the end that goes on the carb goes in a slot not in a hole if that helps, kind of a bear to work on. Steve
...See More
Husky 51 Manual Request
Q
Comments (1)
Just go to Husqvarna's website. Fish
...See More
Husqvarna 51 Chainsaw Overheat?
Q
Comments (2)
Jeff; sounds like more of a coil breaking down issue . Have you checked your sparkplug colour . If your fuel filter was plugged same symtoms could appear also . A loose carburator flange nut or leaking fuel line allowing a overlean condition can also cause this condition check out the plug and other carb situations 1st otherwise I would lean towards the coil .
...See More
Is the 'Husqvarna 51 Chainsaw Overheat' the most recent
Q
Comments (0)
Is the "Husqvarna 51 Chainsaw Overheat" the most recent Husqvarna Chainsaw post vs one that was discovered to have a bad cyl through the plug's hole (maybe yesterday)? The saw had given 15 yrs of family service. There were parts and new saw cost info, along with an interest of a STIHL replacement. Was this post pulled for some reason or where is it? Can you see enough through the plug's hole w/o a camera to make a good diagnosis vs removing the 2 cycle's muffler and inspecting through the exhaust port? loger
...See More
loger_gw
10 years ago
rcmoser and other Techs, is it time to check the connector rod to crank bearings at this point? I retired an 80s Poulan S25 for parts since I own 3 (med grade saw). I was feeling/seeing too much wear in the stroke away from TDC (during a PM vs throwing a rod and trashing parts). I actually feel it was an accident to spot the wear since I was not looking for it vs spotting it.

husqvarna 51

Comments (3)

rcmoser

philp1863
Original Author

Related Discussions

loger_gw

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

husqvarna 51

Comments (3)

rcmoser

philp1863Original Author

Related Discussions

loger_gw

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

philp1863
Original Author