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191T Engine rebuild, muffler mod, “H” screw mod, oil pump

Post in 'The Gear' started by Boog, Mar 23, 2013.

  1. Boog

    Boog Minister of Fire

    Joined:
    Oct 31, 2012
    Messages:
    592
    Loc:
    NE Ohio
    191.1st.jpg

    I originally bought this saw new around 1992. I did use it to do some work up in a few trees back then, but for most of its life its been a ground dwelling limber. Finally, about 2 years ago, it broke its connecting rod, punched a hole in the upper crankcase cover, and died. With the help and guidance of some good folks here, I rebuilt the engine last October with a used OEM crank and upper cover off ebay, and new OEM rings, wrist pin and bearing. The piston and cylinder still looked great after 20 years!

    I also rebuilt the carb and noted at that time that the high speed screw had a plastic limiter with a raised tab on it restricting the travel of the high speed screw. I reassembled it as was, but I always regretted not cutting that limiter off when I had access to it and vowed that I would do it some time in the future. I continued cutting with it all winter up till now. My opportunity came last week!

    I had recently replaced the 14" .063 picco bar with a 16" .050 picco bar. I got a great deal on a GB bar with "Oregon/Carlton" chain for $29 shipped off ebay (also later snagged 3 Stihl "PM" chains for it). I had only cut with it a little bit (awesome) and became concerned at the minimal amount of oil being slung off the chain. I took the bar off and ran the saw watching the oil outlet closely .................. lots of air bubbles in the oil..................... definite problem, I had a significant air leak somewhere in the oiler system! Based on the design of the 191T, I figured it was either a worn pump, or air leakage around the pump hole where the "oil line boot" fits into it.

    I decided to tear the whole saw down again and addressed the following issues.

    1) I installed a new OEM oil pump.
    2) I cleaned all the surfaces of the oil line boot and the case pump hole, and applied a liberal bead of gasket sealant (flexible, oil resistant type) to the boot before inserting it into the oil pump hole. Once inserted, I applied a little more around the outside of the joint. This dried up to a nice flexible seal instead of just relying on "tight fitting parts" to seal the oil channel.
    3) I cut the plastic limiter tab off of the high speed screw to gain full range of motion and adjustment.
    4) Lastly, since I could now adjust the H screw, I cut 3 additional "slit ports" in the muffler opposite the case opening.................. MUFFLER MOD! These can later be bent open more like the original 3 openings if I desire.

    I finished it all up last night and WOW................ does this baby CUT! The closest thing to a limbing "light saber" I’ve run yet! The "Oregon/Carlton" chain on it actually seems to cut nice, but I can't wait to wear it out so I can open my first box of old style "PM" chain!

    Until "MM" clarified the point recently, I never realized that the 191 has 50% more cc displacement than the 192 (46.5 cc vs 30 cc). And to think I almost got rid of this little "magnum" saw in favor of the "newer/better" MS192T. NEVER!

    191.2nd.jpg


    191.3rd.jpg

    191.4th.jpg

    191.4.jpg 191.3.jpg

    191.b.jpg
    smokinj, basod, DexterDay and 3 others like this.

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  2. DexterDay

    DexterDay Guest

    So Boog.... What do you want for it? lol.

    Nice rebuild. That saw should last another 20 yrs.
    smokinj likes this.
  3. Boog

    Boog Minister of Fire

    Joined:
    Oct 31, 2012
    Messages:
    592
    Loc:
    NE Ohio
    Let me see now ............................ that was a pretty sweet looking ATV you were using in your recent post! :p
    DexterDay likes this.
  4. DexterDay

    DexterDay Guest

    How many saws are in your arsenal?
  5. Boog

    Boog Minister of Fire

    Joined:
    Oct 31, 2012
    Messages:
    592
    Loc:
    NE Ohio
    I'm down to only 15 now..... :( ...... 6 of those being the 031AVs that I'll be painting up as soon as the weather cooperates!
    DexterDay likes this.
  6. MasterMech

    MasterMech Guest

    _g ;lol

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