Jonsered 2065 Lean

[Guydreads]

So, I recently converted my 2065 over to 52mm bore. As you may know, the 2065 had a Zama carb on it... I've heard of these carbs not doing great with 52mm kits. It runs well on the high end, cuts and everything... But it won't idle. Very lean on the low jet. Any suggestions? New carb? Thanks

[DHansen]

If your positive it's too lean at idle, my first step would be to disassemble and clean the carburetor.  Paying attention to the idle fuel flow circuit in the carburator.  I have very small drill set (numbered) and just use my fingers with the bits to make sure the brass jet is clear.  Compressed air is a big plus for cleaning.  And those spray cans with little tubes help push fluid through so you can follow the circuit trough the disassembled carburetor.   If needed, and still too lean after cleaning, and you use care as to not ruin the carb you can go up one drill size in the jet.  And if you enlarge the jet you can't make it smaller, so go a little at a time.  And a smooth hole in the jet is important.  A drill mark left in the brass can cause a swirl affect and cause the new large hole to be leaner.  I have done this on lean emissions style carbs on dirt bikes, outboards and mowers.  Only when there is a reason and need.  The days of buying a new jet one size up seems to be disappearing.  

[Guydreads]

Ok thanks. 

[DHansen]

Is there any information of what others have done after the larger piston and cylinder were installed.  Is there a carb available for that p/c combination?  I know I'd try to fix the carb I already have, but that is just me.  Can be time consuming, but successful if you go slow and not go too large right away.  Can't go backwards after going too large with the drill bit.

[Guydreads]

The Walbro carbs do just fine with the 52mm kits, it's just the Zama that I've heard problems with. That's more what I'm asking. I've disassembled the carb before to find it clean as a whistle. I was wondering if you actually have to modify/replace carbs when doing it. @Spike60, do you have anything to say to this thread? Thanks

[DHansen]

 

  This is a photo of one of the carburetor drill sets I have and use.  I have had this set since 1980 and the biggest issue is not to drop one.  There hard to find on the shop floor.  But they do the job when it's necessary.  When you are modifying you need to be able to compensate for the changes.

[Guydreads]

Yes, I have a set of micro drill-bits similar to that. I'll look into it soon

[barbender]

I've had several consumer grade pieces of OPE that are too lean from the factory, and are apparently jetted that way. Like someone mentioned, emissions compliance. So they will jet stuff too lean to even run correctly, but then people will turn around and say the manufacturers would NEVER run the oil mixture too lean at 50:1 to make emission standards because it would decrease engine longevity. I say bull puckey. 

[Spike60]

Those carbs aren't all that good even on the stock saws. Never liked 'em. Going to the 52mm might starve it on the hi end, but I wouldn't think it should affect the lo speed circuit. If anything, I'd think it would be an acceleration problem, not an idle issue.  Think your problem may be a dirty or shot lo speed circuit in the carb. Was the 48 mm kit you removed the early open port jug, or the later, (and way better), 2165/365 special closed port top end? Check for cracks in the throttle cable holder right where the 2 little nuts are too.

DHansen's diagnostic advice is spot on, so try that and see what results you get.

BTW, we're talking about a stock top end, right? Too much enthusiasm with the dremel and you can't get the idle and acceleration to get along with one another.

[Guydreads]

The original 48mm was the open port unfortunately. The p&c are stock, I took a dremel to some rough edges on one tiny section (due to being AM). When I bought the saw for 50 bucks (great deal imo) it was scored up. Another thing I'm going to try is to stick one of my Walbro carbs on it (I have a couple 2071's that I could borrow a carb from) and see how it runs. 

[Spike60]

Yeah, that's the way to go and that will tell you right away if the carb is good or bad. With some of these projects it's nice to be able to grab a carb or coil from another saw that you know is good when chasing some nagging issue like this.

[Guydreads]

Well, I'm happy, because I got it working. I took the carb off, got my compressed air out, and blew er out. Put it on, ran great. Thanks guys! It seems to run well, despite needing a high flow muffler lol... Typical OEM Jonsered sluggish muffler. Thanks again. When I get a piece of wood to cut I'll upload a vid maybe. I'll see if I can get a vid of it running. I have it on my phone, just need to get the vid up here via YouTube channel

[Spike60]

That's good news!

As far as the muffler goes, that entire chassis used, and still uses, the same muffler. Here in the US, mostly just an empty can with the top exit. It's a decent muffler, but opening them up does help.

There have been other mufflers on the IPL's such as the "jungle" muffler with the tube exit on the right side. And I've also run across a couple of top exit mufflers with baffles in them. It's an OEM item, but not sure if they came on the saw, or were something you could order at some time. Didn't think it sounded all that different.

[Guydreads]

That's interesting... after re reading what you said mine actually has the jungle muffler on it. I wonder if it's a part off a 2071? I know both of my 2071's have the jungle muffler

[Real1shepherd]

Well, I'm happy, because I got it working. I took the carb off, got my compressed air out, and blew er out. Put it on, ran great. Thanks guys! It seems to run well, despite needing a high flow muffler lol... Typical OEM Jonsered sluggish muffler. Thanks again. When I get a piece of wood to cut I'll upload a vid maybe. I'll see if I can get a vid of it running. I have it on my phone, just need to get the vid up here via YouTube channel

Carbs need to be soaked in some kinda sauce to get them really clean(USC's are great) and they need kits if you want the best outa them.....you got lucky.

There are other services usually available to 'host' pics and videos that are easier to use than YouTube. Here you can enter them into a gallery from your PC or phone.

Kevin

[Guydreads]

I had already put a carb kit in it. I was foolish enough to think it was clean

[Real1shepherd]

I had already put a carb kit in it. I was foolish enough to think it was clean

Well, lots of folks make the same mistake on cleaning carbs. Tilly's for example have a couple of places(under Welsh plugs and in screens) that can collect crud.

Kevin