Jonsered 672 conversion. Could use some help

[huskihl]

Which carb gasket did you use? Did it come in a kit or did you make it, do the impulse holes line up correctly?

I bought one off ebay. 23hs sticks in my head. The p/c kit I bought had gaskets with it. Impulse hole although small, did line up. I had to trim the center large hole a bit to get it flush with the carb bore

 

[pioneerguy600]

I bought one off ebay. 23hs sticks in my head. The p/c kit I bought had gaskets with it. Impulse hole although small, did line up. I had to trim the center large hole a bit to get it flush with the carb bore

That gasket was always a problem with these Jonsered to Husqvarna swaps, just thought I would ask.

 

[Cantdog]

Ran lean until a month ago. Replaced crank seals and orings (making sure the pto side didn't turn inside out) and rebuilt the carb. Fired it up, retuned, and ran like new with no lean symptoms. It was a bit low on compression at 100 psi, but still ran well. Upon disassembly yesterday I noticed about .100" ring end gap. So it just needed a ring. My goal wasn't to get it back to stock. I like tinkering on this stuff like you guys. Figured it'd be cool to try it AND get a 72cc saw out of it.

OK.....now is this the 52MM Simonian Kit with the Meteor P&C, carb bolts and manifold. Hope you don't mind all these questions.....just trying to see/understand what has been done so far..

 

[huskihl]

That gasket was always a problem with these Jonsered to Husqvarna swaps, just thought I would ask.

Yep. I've read that here. That's why I checked every gasket as it went on

 

[pioneerguy600]

OK.....now is this the 52MM Simonian Kit with the Meteor P&C, carb bolts and manifold. Hope you don't mind all these questions.....just trying to see/understand what has been done so far..

Just went looking for you, see you found it on your own, turned over to you.

 

[huskihl]

OK.....now is this the 52MM Simonian Kit with the Meteor P&C, carb bolts and manifold. Hope you don't mind all these questions.....just trying to see/understand what has been done so far..

I don't mind at all. That's why I posted the thread here. I knew we'd figure it out. It's not from simonians. It's a no name 272xp p/c, 272xp intake block, and new 272xp carb bolts with sleeves

 

[SawTroll]

I believe the black tag makes it a '98, not sure though, that could be just a Husqvarna thing.
The changeover from silver to black was right around there somewhere.
I think the really early ones also had the two piece ignition.

A 1998 number plate would have said "1998" on it, as well as the serial number - to distinguish them from the 1988 ones.

 

[Cantdog]

I don't mind at all. That's why I posted the thread here. I knew we'd figure it out. It's not from simonians. It's a no name 272xp p/c, 272xp intake block, and new 272xp carb bolts with sleeves

The first thing I would make sure of is that the sleeved bolts are not to long. I've had this happen before...you put it all together correctly and tighten the carb bolts until good resistance is felt....nice and tight....but if the bolts are any to long and or/ the gaskets any to thin the bolts bottom out in the holes before taking up properly so you're leaking air and losing impulse. Not sure this is your problem but it is something to check and rule out if it isn't....and with no name AM stuff you gotta look at all the angles , 'cause you never know what shortcuts have been taken...

 

[Cantdog]

Just went looking for you, see you found it on your own, turned over to you.

LOL!! Hey Jerry!!

 

[huskihl]

I'll head out to the garage after the Lions beat the Packers and take some pics. It's a really clean mod that looks stock. Only problems are 1) the left carb bolt is lower than the saw casing and hard to get at. And 2) the choke lever was 1\4" short so I heated it and lengthened it so it matched the full open choke position

The first thing I would make sure of is that the sleeved bolts are not to long. I've had this happen before...you put it all together correctly and tighten the carb bolts until good resistance is felt....nice and tight....but if the bolts are any to long and or/ the gaskets any to thin the bolts bottom out in the holes before taking up properly so you're leaking air and losing impulse. Not sure this is your problem but it is something to check and rule out if it isn't....and with no name AM stuff you gotta look at all the angles , 'cause you never know what shortcuts have been taken...

Yep. Understood. The bolts protrude a half inch into the cylinder, which is tapped about 3/4" deep.

 

[Cantdog]

I'll head out to the garage after the Lions beat the Packers and take some pics. It's a really clean mod that looks stock. Only problems are 1

Yep. Understood. The bolts protrude a half inch into the cylinder, which is tapped about 3/4" deep.

OK so you've got room to tighten up properly.....so that's not he issue......a 272 carb is not going to do it either.....though it will bolt up fine, Jonsered has the high idle operated by and built into the choke linkage...the husky does not...the high idle is in the trigger handle on the throttle linkage so the best carb for this setup would be from a 670...

On the lower bolt...if you don't have a ball end allen wrench,, cut 3/8-1/2" off the short leg of a regular allen wrench and you'll be able to reach right in there.

However your carb should run it fine though perhaps not with optimum power output....so.....the carb has been rebuilt with a new kit and the 625 ran fine on it...yes?.....you've replaced the crank seals and oil pump housing o-ring...yes?...cyl base gasket new ..yes?... did you put the cyl base gasket in dry or use a sealent?

Why was the choke lever to short????

 

[huskihl]

OK so you've got room to tighten up properly.....so that's not he issue......a 272 carb is not going to do it either.....though it will bolt up fine, Jonsered has the high idle operated by and built into the choke linkage...the husky does not...the high idle is in the trigger handle on the throttle linkage so the best carb for this setup would be from a 670...

On the lower bolt...if you don't have a ball end allen wrench,, cut 3/8-1/2" off the short leg of a regular allen wrench and you'll be able to reach right in there.

However your carb should run it fine though perhaps not with optimum power output....so.....the carb has been rebuilt with a new kit and the 625 ran fine on it...yes?.....you've replaced the crank seals and oil pump housing o-ring...yes?...cyl base gasket new ..yes?... did you put the cyl base gasket in dry or use a sealent?

Why was the choke lever to short????

Yes to all. Sealant on base of cyl. No idea on the choke lever. My filter elbow has the vertical bolt hole on the right side. But the whole assembly is about 3/16" short of reaching that hole. Either the intake port on the cylinder is milled too short, or the fiber block is too thin, or the 12 yr old Chinese girl that made them had to walk home to do chores and quality control missed it

 

[Cantdog]

Yes to all. Sealant on base of cyl. No idea on the choke lever. My filter elbow has the vertical bolt hole on the right side. But the whole assembly is about 3/16" short of reaching that hole. Either the intake port on the cylinder is milled too short, or the fiber block is too thin, or the 12 yr old Chinese girl that made them had to walk home to do chores and quality control missed it

Hmm that's weird. Does that muff up the holes to adjust the carb?????

Sealant.....what and how much did you use? It only takes a tiny bit of squishout to fill the impulse corridor.....especially something like RTV or other silicone based sealers as they are the hardest to apply very thin. When using a new stock gasket I put them in dry....but that's just me.

 

[huskihl]

Hmm that's weird. Does that muff up the holes to adjust the carb?????

Sealant.....what and how much did you use? It only takes a tiny bit of squishout to fill the impulse corridor.....especially something like RTV or other silicone based sealers as they are the hardest to apply very thin. When using a new stock gasket I put them in dry....but that's just me.

Carb adjust holes line up fine through that boot. Actually straighter than before. Case sealant on the bottom of the jug only. None on intake or carb gaskets

 

[Cantdog]

Carb adjust holes line up fine through that boot. Actually straighter than before. Case sealant on the bottom of the jug only. None on intake or carb gaskets

That's the most likely place for sealant to clogg the line....make certain this passage is clear. Air has to flow freely in both directions. Also how did you plug the impulse hole in the carb top? Wouldn't take much of a leak there to mess thing up too. You can simply use any solid HS top from a husky or any other Jonsereds that impulses through the manifold.

 

[huskihl]

That's the most likely place for sealant to clogg the line....make certain this passage is clear. Air has to flow freely in both directions. Also how did you plug the impulse hole in the carb top? Wouldn't take much of a leak there to mess thing up too. You can simply use any solid HS top from a husky or any other Jonsereds that impulses through the manifold.

I'm working on it now. Gave up on the Lions lol. I think I found my problem. When I drilled the impulse into the carb, without looking at it I only drilled to the first hole, which happens to be the locator for the top cover. I had to drill it 1/4" further to get to the impulse passage. I also had to drill the top cover down on an angle to hit this passage. I think I've got it now. I'm gonna fire it up in a few and find out. I temporarily left the top cover impulse elbow intact and plugged it with a 1" piece of tygon line and a bolt.

 

[Cantdog]

I'm working on it now. Gave up on the Lions lol. I think I found my problem. When I drilled the impulse into the carb, without looking at it I only drilled to the first hole, which happens to be the locator for the top cover. I had to drill it 1/4" further to get to the impulse passage. I also had to drill the top cover down on an angle to hit this passage. I think I've got it now. I'm gonna fire it up in a few and find out. I temporarily left the top cover impulse elbow intact and plugged it with a 1" piece of tygon line and a bolt.View attachment 390173

Sounds good let us know how it goes.....

 

[huskihl]

I guess we all get a little bit smarter every day. Yesterday was my first time drilling an impulse passage into a carburetor. I looked at it today and just shook my head. I also had to drill the top cover (shown above) on a hard angle to connect this passage to the pump cavity. Just goes to show us all how many different carbs they used on these models probably even in the same year models. I only say that because of reading a couple hundred threads on this subject never revealed drilling the cover also.

Anywhooo. Got it back together, pulled it 5 times and it fired up running really rich. That made me smile . Got it back to about 1.5 turns out (about a quarter turn rich until I get a couple tanks through it). Runs like a million bucks. Can't wait to make some chips.
Violá. The Husqered 672.

 

[huskihl]

Sounds good let us know how it goes.....

Kudos to Cantdog, pioneerguy600, wcorey, weimedog, and Saw Troll for helping on this project. Collectively, your wealth of knowledge is noted and appreciated.

 

[weimedog]

Actually did a video on blending 670/272 carbs.... saw ran but had a crappy AM cylinder. AND found out at a later point in time the clutch side bearing was going bad.... moved the "blended" carb to another saw and it worked fine.

I had forgotten about this one...