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Rebuilt first yanmar diesel – smokes a little at high load/throttle? rings need to seat?

sepulchral ยท 2021-09-03 07:30

Hi, i rebuilt a 4tnv98 in a takeuchi tl130, new pistons, rings, rods, bearings, gaskets - within 5 minutes of first firing up i drove the skidsteer around and at max throttle high load (two speed going uphill) it smokes. was driving it at 3am so i couldnt tell the smoke color - positive note is that it ran great. what is the process for seating the rings? I think i put maybe 1/3 to 1/2 gallon of too much oil in it but i dont think that should cause it. Its non turbo btw. Maybe i need to adjust valves?

Replies6
  1. #1sepulchral2021-09-03 07:32

    by the way, at idle the oil cap will sit and bounce around on the oil fill neck, not enough blowby to push it off onto the ground. so i guess thats good

  2. #2_Weldman_2021-09-03 09:38

    Did you hone the cylinders or put in new liners?

  3. #3sepulchral2021-09-03 11:08

    I honed them. Wel I ran machine hard and it smoked real heavy for 10min then shut it off and smoke was still coming out of muffler. Like burning oil. Started again an hour later and zero smoke at high load. Might have been residual oil

  4. #4Birken Vogt2021-09-03 11:41

    I have always been told rebuilding engines of this class the box of parts costs as much as a new engine from Japan. How did that part work out for you?

  5. #5sepulchral2021-09-04 17:56

    Dude I emailed the Chinese folks on Amazon for pistons and rods and bearings and they sold me what I needed for $480 shipped I measured the weight of pistons new versus old and mic checked all dimensions and they were exact. High quality parts too

  6. #6mekanik2021-09-04 19:26

    The oil from assembling the engine can take a while to burn off. I would run it and see if it clears up. As far as break in don't idle it and just work it as you normally would.