Jonsered 2065 turbo backfired a few times???

[MAF143]

Another friend of a friend brought me his Jonsered 2065 with a broken chain tensioner and he wanted muffler mod also. I was busy when he dropped it off and I never started it while he was here. My mistake...

A couple days later when I got to it, I started it but it would barely idle and backfired a couple times when I tried to give it throttle. I didn't think much about it and ordered a carb kit for it and did the MM.

I started it after cleaning the carb and putting in the kit and checking the lever level. It all looked OK, but when I started it it backfired once. Then it would idle, but not take throttle. I played with the tuning some but it just doesn't respond like normal. It flooded a couple times and I had to change plugs to get it to start again.
I took the carb off and checked the metering needle valve to make sure it is seating and opening properly. It holds pressure like it should when closed.

Being a rookie at carburetor diagnosing, I'm just assuming the carb is bad and needs replaced.

Has anyone run into similar symptoms? I hate to order a carb if it could be the ignition coil or something else.

I did check the flywheel to coil gap and it was a little big so I re-set it to .012 but that made no difference.

Thanks for any suggestions.

 

[Ronaldo]

Possible the flywheel has slipped/ spun on the crank?

 

[MAF143]

I had it off and back on. I had given it a 5* advance while doing the MM. It actually backfired less after the advance. Hmmm, maybe coil?

 

[Woodslasher]

Long story short, my brother's 372 ran erratically, smoked, sputtered etc one time and ran fine the next for months. I tore it down to put new seals in figuring an air leak and 2 years later when I reassembled it the coil was dead. I swapped over the blue coil off my XPW and it's run fine for 3-4 years now. I always thought coil problems were either "die when warm" or "die", but running issues can be caused by a dying coil. A buddy's friend's car's coil would be dead when cold and start working when it was warm, go figure.

 

[MAF143]

I did vac / pressure test on it and all is good, except on the pressure side it would bubble a little between the carb and the intake rubber but only on pressure. Wacuum was OK. I put a thin film of Moto Seal on that side of the carb on re-assembly. That fixed the pressure leak, but NO change on the running issue.

I ordered a carb and have a coil in my in-basket if the carb doesn't fix it.

I've run across a few kooky situations over the years that complicate trouble shooting and diagnosing problems with engines of all sorts. I've always been OK with changing a cam or pistons to bump up powa, but troubleshooting a no start or stumble / miss condition has never been my strong suite... I hate just swapping parts, but I've had to do that a few times.

I'm learning to work on chainsaws because I heat with wood and enjoy tinkering, but I'm a weekend warrior and rookie at it. Sometimes the issue is very easy to fix and other times my brain is pushed to its limits but that's when I'm learning more. Most of the saws I end up working on have been rode hard and put away wet and the folks bringing them to me have to heat with wood to get by and have no money to buy a new saw. I try to help out with low cost repairs for them because most of the time they've already taken the saw to a shop and was told to toss it and buy a new one.


Thanks for the help and support with all your knowledge and experience.

 

[hacskaroly]

. I hate just swapping parts, but I've had to do that a few times.

Swaptronics is a valid way to troubleshoot, though not always cost effective. You can quickly identify a problem component or assembly. Once identified as an issue, then you can tuck away that knowledge for later when you come across a similar issue again.

 

[Woodslasher]

Take the coil off the 357 in your sig and try it to see if it makes a difference, it's the same coil that the 2065 has.

 

[MAF143]

Thanks, that's awesome!

 

[MAF143]

Tried my 357 coil on the Jred 2065 and it didn't make any difference as far as running and tuning, but no backfires, but the Jred coil on my 357 didn't want to run and it backfired once... so I'm figuring both the coil and carb need replaced on the 2065. In looking for parts it is a different cylinder (open transfers and wide oval / rectangle intake) than any of the parts lists or AM stuff I've seen. I'm not overly familiar with the Jred product lines but it was a little confusing. A similar thing happened to me when I was searching for a replacement jug for a MS391. I was only able to find a couple jugs that had the same intake configuration and the owners all thought they were gold plated or something...

I'll get a carb and a coil on order for this thing...

I had forgotten that the 357 coil I had was a little beat up... apparently the previous owner had a bearing go out and the flywheel kicked the laminations of the coils butts... I cleaned it up so it didn't score his flywheel the same way my 357 is scored... That saw is beat up and looks rough, but it runs great after I rebuilt it a few years ago.

 

[Chainmale]

Take the coil off the 357 in your sig and try it to see if it makes a difference, it's the same coil that the 2065 has.

Some good info there!

 

[Chainmale]

In looking for parts it is a different cylinder (open transfers and wide oval / rectangle intake) than any of the parts lists or AM stuff I've seen.

My 2065 is the same. Open transfers. Intake block instead of boot. And front chain tensioner. Definitely not as common.
Unfortunately no info on the carbs for you though.

 

[Kiwioilboiler]

My 2065 is the same. Open transfers. Intake block instead of boot. And front chain tensioner. Definitely not as common.
Unfortunately no info on the carbs for you though.

Not Special.

 

[Chainmale]

Not Special.

No 2165 is 365 special?
Think it was the early 2065 were open port then went to closed.