@17:20 The crankshaft is moving but the piston stays still. That means the bearing clearance in the crankpin journal is much too large. I had a Tecumseh LEV120 (195 cc, about 5 HP) that got hard to pull, especially in a few spots like TDC and BDC. The clearance was far above what it should be.
@@woodysgarage469 I can't think of any other reason besides excessive clearance that would explain the piston not moving when the crankshaft is turned. It is most noticeable at the top and bottom when the piston is changing direction. It does not take a lot to be too much. Rule of thumb for plain bearings is 3/4 - 1 thousandth per inch of diameter, and the crankpin journal is about an inch in diameter. A piece of blue Plastigage can tell you quickly and cheaply. It will read 4 - 9 thousandths accurately. Mine was a bit off the scale on the loose end, and I do not recall it feeling obviously excessive.
I think I just gave up on it. When I got it it a new looking piston, and when I pulled it out it was covered in fine metallic particles. So I'm not sure if that messed up the bore or what. I tried to spec it out, but found a lot of different specs out there, I couldn't even figure out what the piston should look like, flat or skirt.
Using that pulley to turn the motor over isn’t doing you any favors. When I lap the flywheel I can tighten the flywheel nut with no key and still spin it over by hand to check for spark
@17:20 The crankshaft is moving but the piston stays still. That means the bearing clearance in the crankpin journal is much too large. I had a Tecumseh LEV120 (195 cc, about 5 HP) that got hard to pull, especially in a few spots like TDC and BDC. The clearance was far above what it should be.
That would be odd. The rod seemed to fit correctly, there was no gap that I remember. Maybe I'll get back to it someday with that in mind. Thanks.
@@woodysgarage469 I can't think of any other reason besides excessive clearance that would explain the piston not moving when the crankshaft is turned. It is most noticeable at the top and bottom when the piston is changing direction. It does not take a lot to be too much. Rule of thumb for plain bearings is 3/4 - 1 thousandth per inch of diameter, and the crankpin journal is about an inch in diameter. A piece of blue Plastigage can tell you quickly and cheaply. It will read 4 - 9 thousandths accurately. Mine was a bit off the scale on the loose end, and I do not recall it feeling obviously excessive.
@@jimmonte9826 Thanks Jim.
Did you ever figure out why it was so hard to pull and breaking flywheel keys ? I have this same engine . Thx
I think I just gave up on it. When I got it it a new looking piston, and when I pulled it out it was covered in fine metallic particles. So I'm not sure if that messed up the bore or what. I tried to spec it out, but found a lot of different specs out there, I couldn't even figure out what the piston should look like, flat or skirt.
@@woodysgarage469 ok, makes sense. It Let's me know what I may get into b4 tearing mine down... Thanks !
@@gebwv84 I wouldn't use this one as an example, yours will most likely be much easier to repair, this was an odd ball.
Using that pulley to turn the motor over isn’t doing you any favors. When I lap the flywheel I can tighten the flywheel nut with no key and still spin it over by hand to check for spark
Thanks for the tip.