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Jonny 2152c

Discussion in 'Chainsaw' started by holeycow, Jun 13, 2019.

  1. holeycow

    holeycow Addicted to ArboristSite

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    hello folks,

    I bought this saw many months ago and only ran it long enough then to confirm that it ran good (warmed it up, made a few little cuts and a couple of 10” bucks and shut it down) and that I really liked how it felt! It was cooler weather then too.

    Over the winter I got a Chinese muffler to replace the original cat muffler and finally started running the saw for real a few days ago. What a fantastic saw!!! It’s fairly light, has decent power and handles remarkably. The handling is the best part of this saw, imo.

    Anyway, here’s the problem: after initial warmup the saw runs perfectly. When it gets up to full operating temperature (maybe 5-10 minutes of limbing, bucking and throwing - clearing trail of mostly deadfall) it starts to feel lean, it bogs badly coming into the upper revs, and the idle races and hangs a bit (somewhat intermittently).

    I’m pretty sure it gets to running lean when it is fully warm, and runs perfectly when not quite hot.

    I trimmed the high speed tab with the saw all together when I changed mufflers. It’s a little harder to get the tabs off of the low screw without pulling the carb, so that isn’t done yet.

    Today, I popped the gas cap a few times when it started to bog. It didn’t really make a difference. If I let it idle or run at low revs for a short time it will run normally for a cut or maybe two (6” wood or so) and then it bogs hard again. I tried pulling the choke once to see if I could increase fuel to air a little and the saw died instantly. I didn’t fart with that much, I couldn’t easily get a part choke, so it went to full choke and instantly cut off the air. So no surprise really,

    This saw has the steel intake clamp and has no purge bulb. I can’t even find a serial # on it??, so I don’t know what year it is, just that it is a “green cap” saw and most likely a Canadian model.

    I’ve read about some common issues with intakes and carbs and possibly even coils??

    I haven’t investigated this hardly at all yet, but someone may have some knowledge to make my troubleshooting quicker.

    Much appreciated!

    I think I might just have a blockage in the carb somewhere. I have only gone so far as to pull the cap and the diaphragm. It doesn’t look dirty or cruddy at all under the diaphragm. The meter lever “looked” reasonable but I never measured any thing yet. It could be way off, but I believe the saw to be totally unmolested as it appears new inside (p&c from exhaust side) and the fasteners didn’t appear to be touched. Several of those were loose-ish, including the muffler bolts, just like a saw that had been run a bit and never touched. I think the bar and chain are original and barely used.

    Why would it run perfectly when cold and act up when hot?

    Thanks
     
  2. Ronaldo

    Ronaldo Addicted to ArboristSite

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    First thing to try is a new spark plug or a known good one.

    Sent from my SM-S320VL using Tapatalk
     
  3. Terrence Jefferson

    Terrence Jefferson ArboristSite Operative

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    I would do a pressure and vacuum test on it. You may have a crank seal leaking. That is a nice saw and they like the transfer covers cleaned out and the base gasket removed. Hope this helps
     
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  4. holeycow

    holeycow Addicted to ArboristSite

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    Unfortunately I haven’t the tools to do a pressure/vac test at this time. Rolling the saw around while it’s running seems to have no effect on it. A rough check I suppose.

    Spark plug? Hmmmm. Maybe?

    It’s a busy time on the farm and I’m not sure if I’ll be pulling things apart anytime soon. But it is bugging me that my new favourite saw has an issue, so you never know. I need a saw almost every day and I have others. But I like this one a lot! Whaaa.

    Anyway, I was hoping that my saw is suffering from a common issue of this model/series..and someone knows what that probably is.
     
  5. brad ruch

    brad ruch ArboristSite Guru

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    If you don't have a pressure vac tester.you can spray some brake cleaner around the intake, cylinder base,carb,threw the pull start ect anywhere a air leak could be.if the saw dies you found your where your leak is.

    Sent from my Pixel 2 XL using Tapatalk
     
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  6. holeycow

    holeycow Addicted to ArboristSite

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    Carb cleaner? Contact cleaner? WD40? I’ll use those before brake cleaner.

    Yup that’s what I’ll do.

    I guess I’ll have to go thru the steps.

    Something I noticed that seems weird is that the whole body of the saw moves just a little at the end of the throttle pull. The crankcase is pushed slightly away from the gas tank/rear handle. Is that normal for these?
     
  7. holeycow

    holeycow Addicted to ArboristSite

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    Spraying solvent around showed no change.

    So I cleaned the carb. Not a complete disassembly type clean, but a spray carb cleaner and air thru every available hole kind of clean. It wasn’t very dirty, but there was a tiny bit of obvious sludgy brown stuff in there. I’ve seen worse that still ran fine.

    Anyway, I “think” it’s fixed. :chainsaw:

    I’ll have to go cut some wood to know for sure.

    And now I know how to take the saw down at least that far. It’s a little finigly, but not bad.

    It’s weird that the crankcase moves at the end of the throttle rod travel. I guess that’s what some rubber mounted carb set-ups do?
     
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  8. eat a peach

    eat a peach ArboristSite Operative

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