Been having trouble with it. Took carb off today and cleaned it. I noticed the foam or rubber gasket that sits below the carb was gone. It needs that to run correctly am I right? Something to do with the pulse ?
Jonsered 670 question
- Thread starter eric_271
- Start date
Help Support Arborist Forum:
captain dangers
partner 1633B (skil) chainsaw
the foam pad I think your referring to is to support/steady the carb because of vibration etc? the pulse line if its external is important to the saw starting as the vacuum created by the engine turning over passes through the pulse line to the carb diaphragm which in turn pumps the fuel to the carb. no vacuum = no fuel to the carb. if it's an external pulse line ? the same as a 535 etc then its easily changed using long nose pliers. although I think you will still need to remove the carb to fit it to the nipple on the crankcase. if it has the rubber intake manifold held on with a piece of twisted wire, like a sack of tatties? this could also be your problem as these can split and go porus. if the carb is bolted direct to the cylinder with a solid plastic manifold? then I doubt your trouble would be a vacuum related problem unless they was an obstruction in a port hole on the carb or manifold? warn crank seals wil also cause a vacuum failure resulting in fuel starvation in severe cases. good luck captain dangerous
captain dangers
partner 1633B (skil) chainsaw
I forgot to mention! did you check the fuel line and filter for failure/blockages ? fuel lines don't last forever and filter do block up. regards captain dangerous
All lines are brand new as is the fuel filter. I had the carb kitted at the same time. Ran good for a couple of hours when I brought it home but got progressively worse to the point it will start but but then dies. It can't be adjusted to keep it running.. I noticed the foam doughnut which sits under the Dophragm on the carb missing
captain dangers
partner 1633B (skil) chainsaw
when it dies pull the plug out and check if it has a spark straight away as your coil my be burnt out ?
Brand new coil. I called the saw shop who didthe work on it last year. I specifically asked that he check the crank seals when he worked on it. Today he says it sounds like the crank seals are bad. It only has a couple of hours of run time on It since I got it back from him. Obviously I didn't get what I paid for. It starts running like crap just sa soon as it starts warming up
captain dangers
partner 1633B (skil) chainsaw
the crank seals wont be bad to change, and not expensive. as far as I'm aware, you don't need to split the cases? they can be done by removing the clutch and flywheel like Husqvarna. but I'm sure an expert will clarify? regards cd
He said seals were no longer available. I already found new ones on eBay. Hope you're right about not having to split the case.
captain dangers
partner 1633B (skil) chainsaw
be carful not to score the shafts where the seal lip runs, when removing the old seals and apply a little grease to the inside lip when fitting the new ones some people put a little smear of grease around the friction fit part to secure a good seal on the crank case. cd
Will do thanks.
Do me a favor. Take a flashlight and take a close look inside the fuel tank. I have had one jonsered where the paint inside the tank started to blister and it kept plugging the carb. I'm not saying this is your problem but it should be checked.
Thanks and I will check. The fuel filter and carb rebuild only have few hours run time on them. It's been coming on for a while now. Just as it starts to warm up it starts dying. Hi revs when letting off throttle. Could be a lot of things but ive been thinking crankseals for sometime just by how it was acting. Bought it new over 20 years ago and it's been an absolute workhorse . New seals are on the way.
ncfarmboy
Addicted to ArboristSite
He lied to you about the seals being NLA. I just bought a dozen from Jacks. Seals are the same on 266,268, 272, 61,66 Husky. Actually put 2 of them in my 670 Champ. If you change them be sure to get new O-rings too. You do not have to split the case.
Shep
captain dangers
partner 1633B (skil) chainsaw
shep is right where alloy tanks are used, I had an old jondereds 80 do exactly that. but if an old saw has been standing for years with fuel in it. the fuel eventually evaporate and can leave a skin inside the tank which loosens off and can wrap around a filter. but I think yours will have a plastic tank so wont be painted and I doubt it's been standing anytime long enough to develop a film of old fuel ?
- Joined
- Feb 17, 2009
- Messages
- 16,680
- Reaction score
- 15,902
- Location
- Beautiful Rockbound Coast of Maine
The 6XX series has a plastic fuel tank so there will be no paint issues like the older Jonsereds. There a couple different versions of the 670. All 670's use an intake boot...a prime place for air leaks which high revving is a common symptom. There are two different boots.....one has an impulse corridor in the boot, the later ones take the impulse from a nipple at the bottom right side of the cyl. Both boots can leak around where they attach to the cyl. The external impulse hose can degrade and develop leaks or fit very loosely on either the cyl end or the carb end. The early 670, with the two piece ign has a seal carrier under the flywheel, held in place with three screws....this is o-ringed to the case.....the clutch side has the seal actually mounted in the oil pump housing which is again sealed with the same 0-ring as the flywheel side. It is entirely possible your shop did replace the seals but neglected to replace the O-rings. These are not parts store or hardware store O-rings and must be gotten from a Husky dealer or partstree etc.etc. The later 670 with the one piece ign lost the flywheel side seal carrier but still has the oil pump o-ring......again these are very common places to look for air leaks. One other thing that is pretty simple to check is the final fuel filter.....this is located just under the top cover inside the carb. Remove the top cover, and you will find a 1/4" dia, hole right where the fuel inlet is.....down in that hole is a fine screen that can get plugged up and lean your saw out. Food for thought......
This is the 670 champ. All lines are new. Gas tank is plastic and 1 piece ignition. I know for a fact the seals and o rings were not changed. He did get the hi idle problem fixed. I checked the screen in the carb. It was clean. I better get o rings on the way. I'll be surprised if the seals and o rings aren't the prob. Like I said it's gotten bad enough that just as soon as it starts to warm up it dies and then you can't keep it running. Is that a symptom of seals going bad?
captain dangers
partner 1633B (skil) chainsaw
usually an early sign when seals start leaking is that the saw wont tick over properly, they race, which in turn due to the air leak creating a leaner mixture, the cylinders and piston get damaged. When you bought the saw did it have a scored cylinder and piston or had it been replaced? because if it has and the seals weren't? then there's your likely problem. for what the seals cost and take to fit , for peace of mind, at best they will cure it. at worst you can eliminate the seals as a possible cause. cd
captain dangers
partner 1633B (skil) chainsaw
it is quite hard trying to diagnose something via written text. a video upload of the offending saw going through the process would be nice, so we could observe/listen to form more accurate/informed opinions. regards cd
Bought it new. Saw shop did compression check and said it has some wear but good enough compression to last a while yet
captain dangers
partner 1633B (skil) chainsaw
if you bought it new and its an old saw now and it must have done a fair bit of work by now so I would assume its the seals. as far as the compression side goes it will only need a new piston ring, you will feel a significant difference in the way it pulls over with new seals in, if the old ones are warn. stick the seals in and give her ago, I've just been looking in my pile of unopened stock and there's a jony 630 in there, been there 3 months, haven't even looked at it yet, in fact to be honest, I forgot I had it ;o) cd
