jonsered 80

[Dader]

saw has good compression but will not start.in fact it just about pulls my arm out of socket when i try which leads me to believe that the breaker points and/or the ignition setting need to be set correctly. i have not in the past had any problems setting points but adjusting the ignition setting is all new to me.the procedure uses a dial indicator( which i don't have).The correct setting is 7/64 inches before TDC if using the dial indicator.anyone out there have any experience they can share wrt my problem?

 

[farmguywithasaw]

Do you have callipers? They would work too in a pinch you would have to find tdc zero it then go down the specked amount.
Typically it’s the points gap that is out of wack. I haven’t done a 80 so I’m not sure if you can alter the timing any other way. You should be able to see on the points cam about where it should be when you set it

 

[Cantdog]

If you haven't moved the points plate you shouldn't have to fuss with the timing. Pull the flywheel and remove the points. Check the condition of the contacts and carefully file away any pitting or other imperfections taking no more than absolutely needed, keeping the contact faces flat as possible then match the contacts to each.. other......you may have to bend the movable arm to achieve this. Then set the gap to 0.016" If everything else is in good order you should have fire. Any 80 is a hard pull.....on one in good condition it's not uncommon to get readings of 220-240 lbs of compression. You have to pull with great conviction.....not at all unlike starting an old 1200cc kick start Harley.....

 

[Dader]

Thanks Farmguy and cantdog for the info,I'm a little under the weather so it will probably be a few days before i get around to working on the saw.

 

[Dader]

Tried all of the suggestions mentioned previously with no results,even tried the electric drill trick so that eliminates the starter cord binding.I have a large number of saws but i haven't run into this problem with any of them.Any other suggestions would be appreciated.

 

[Cantdog]

Are you certain it's an ign issue and not a carb or fuel line issue? Do you have spark now?

 

[Dader]

Cantdog I do have a healthy looking spark.my problem now is when i pull the starter i get one crank revolution and everything seems to locks up( cant pull cord any further).There's plenty of cord on the starter so that should not be a problem.I'm going to replace the cord with a larger size and see if that helps.You are right about the high compression.Maybe that's the problem as i am getting up there age wise.I haven't had the saw running yet so i can't comment on the fuel lines or carb.

 

[pioneerguy600]

Are you certain it's an ign issue and not a carb or fuel line issue? Do you have spark now?

It is likely a weeping needle/seat issue creating wet cylinder condition leading to hydro lock. Three of my own saws have shown up this year with these symptoms, a quick check with the Mighty Vac showed the needle was not holding either vac or pressure so a carb rebuild along with some seat conditioning fixed the issue on them.

 

[Cantdog]

Cantdog I do have a healthy looking spark.my problem now is when i pull the starter i get one crank revolution and everything seems to locks up( cant pull cord any further).There's plenty of cord on the starter so that should not be a problem.I'm going to replace the cord with a larger size and see if that helps.You are right about the high compression.Maybe that's the problem as i am getting up there age wise.I haven't had the saw running yet so i can't comment on the fuel lines or carb.

Are you trying to start it without a the B&C installed? Funny as it may sound this can be a real issue if you don't as there is no counter weight on the saw and nothing to work against your pull. A 20-24" bar works good for this.
It may well be a hydro lock situation as Jerry described. Especially if you don't know what's going on with the carb. I know all my 80's are hard to pull so when starting I always cold start them on the ground with my foot on the trigger handle stirrup and my left hand pushing down on the top handle. It doesn't take much powerhead movement to overcome and stop the engine roll over.

 

[Cantdog]

Jerry what do you use to recondition an inlet needle seat? I've never had to but have pondered it.

 

[fossil]

My 801 hydro locked with the low needle out 1/8 turn too much.

Came close to rupturing a tendon. I thought it was ignition at first.

It's likely the best starting saw I have.

 

[steele_109]

I have a jonsered 80 as well.It's been a battle but i have the same problem that you have. Pull the cord it will pull a little ways and stop like it locked up.In my case it's not a leaky carb,it's a stubborn old man who won't admit when he is whipped.Good luck.

 

[Tony Mayhew]

I just acquired a Jonsered 80 with no pullstarter on it! The old man who gave it to me said that they are a real beast of a chainsaw to pull over due to the high compression that they have, but 220-240 sounds outrageous! I would have figured that they would have put a decompression valve on them with compression readings like that? I had a honda 250 fourtrax with a nitrous bottle that was 220 pounds of compression, and my foot slipped off the kick starter and it split my shin wide open clean to the bone! I can't imagine a chainsaw with that kind of compression readings?

 

[pioneerguy600]

Jerry what do you use to recondition an inlet needle seat? I've never had to but have pondered it.

I use a dab of toothpaste on a Q tip to sort of scrub the seat, often it looks like a varnish like coating on the brass seat, looking at it under 20 times magnification, whatever it is the toothpaste will scrub it clean and I find the new needle will seat and hold both vac and pressure. Two weekends back my MS440 Arctic had this wet cylinder problem up at the camp, couldn`t pull it over no way. Removed the carb and brought it home, tested and failed so a quick cleanup and kit it then held vac and pressure, took it back up on Saturday and installed it. The saw starts and runs , used it both Sat and today/Monday on some hardwood for next years firewood pile.

 

[fossil]

I just acquired a Jonsered 80 with no pullstarter on it! The old man who gave it to me said that they are a real beast of a chainsaw to pull over due to the high compression that they have, but 220-240 sounds outrageous! I would have figured that they would have put a decompression valve on them with compression readings like that? I had a honda 250 fourtrax with a nitrous bottle that was 220 pounds of compression, and my foot slipped off the kick starter and it split my shin wide open clean to the bone! I can't imagine a chainsaw with that kind of compression readings?

They sure do! my 801 is at 225 psi at 6 pulls.

 

[Cantdog]

I’m in

I use a dab of toothpaste on a Q tip to sort of scrub the seat, often it looks like a varnish like coating on the brass seat, looking at it under 20 times magnification, whatever it is the toothpaste will scrub it clean and I find the new needle will seat and hold both vac and pressure. Two weekends back my MS440 Arctic had this wet cylinder problem up at the camp, couldn`t pull it over no way. Removed the carb and brought it home, tested and failed so a quick cleanup and kit it then held vac and pressure, took it back up on Saturday and installed it. The saw starts and runs , used it both Sat and today/Monday on some hardwood for next years firewood pile.

That sounds like a good way….. I was thinking a used needle with an inch or so of fuel line to hang onto slipped over the lever end. Then a dab of valve grinding compound on the rubber tip then hand lap it in like a valve but that may be a bit coarse. I think toothpaste would be better on the alum seat in a Tilly. I may be having this problem with my 61/268XP conversion saw….. will have to pres/vac test it when I have a minute. Pulled the cord right out of it last time I used it. That hasn’t ever happened in the 10 years since I built it.

 

[pioneerguy600]

I’m in


That sounds like a good way….. I was thinking a used needle with an inch or so of fuel line to hang onto slipped over the lever end. Then a dab of valve grinding compound on the rubber tip then hand lap it in like a valve but that may be a bit coarse. I think toothpaste would be better on the alum seat in a Tilly. I may be having this problem with my 61/268XP conversion saw….. will have to pres/vac test it when I have a minute. Pulled the cord right out of it last time I used it. That hasn’t ever happened in the 10 years since I built it.

When the piston locks up suddenly on a strong pull of the cord I have ripped the center section on the Stihl Elasto start recoil handles, my bad for pulling them over with full force on a drop start, have also broke 5 mm pull cord doing the same.It does not take much work with tooth paste to clean up the seat, valve compound might be a bit too coarse but I too have thought about it and have plenty of long style needles from previous carb rebuilds I could use if needed.

 

[Cantdog]

When the piston locks up suddenly on a strong pull of the cord I have ripped the center section on the Stihl Elasto start recoil handles, my bad for pulling them over with full force on a drop start, have also broke 5 mm pull cord doing the same.It does not take much work with tooth paste to clean up the seat, valve compound might be a bit too coarse but I too have thought about it and have plenty of long style needles from previous carb rebuilds I could use if needed.

Yeah I was thinking about keeping the seat taper correct by using a needle but using toothpaste never would have occurred to me. It pays to ask questions…… sometimes