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Discussion Starter · #1 ·
New to this forum, but not to Lawnboy mowers. I've had two over the last 30 years, and I'm trying to determine if my current mower is worth saving! When pulling the start cord, there was absolutely no resistance. I pulled the shroud to see if the teeth were engaging the flywheel, and all seems correct. I removed the blade to clean everything off good before working on the mower. The flywheel can spin in either direction with no resistance. I also noticed that the "prong" on the sparkplug is mashed down and there was no gap left. This was a big red flag to me. Is this all a sign of a broken piston rod? If so, is it the end of the road for my little green friend? I'm truly an amatuer, but have been able to do most basic services over the years. This appears to be over my head, and I would appreciate any advise. Thanks from Kevin.
 

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Hey Kevin.

Sorry to hear about your old trusted friend. It sure sounds like the connecting rod is trashed.

It's amazing to me that you get no clanking, banging or noise of any kind when you spin the crank. The rod may have broken cleanly away near the crank. With the small end sent north towards the head now the crank can smoothly rotate. If the piston was still attached there would be SOME resistance, and the spark plug would not look hammered.

Now to the question of whether this is the "end of the road". I would pull the bottom end of the case and take a look. If you can disassemble the motor then you can determine what needs to be done.

A new rod, rings and maybe a piston could be worth doing. Extensive case and or cylinder damage would likely not be worth fixing. The only way to tell is to take it apart. One good thing is that these are very simple engines.

I hope this helps,
HDNewf.
 

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Discussion Starter · #3 ·
HDN,
Thank you for your reply. It was helpful and appreciated. I picked up a used LB 4 stroke mower, in very good condition for a great price. That will allow me to play with the old one, and maybe get her running as a back up. Plus, I think it will be fun to learn more about small engines. At the very least, it will be fun doing the disassembly! I guess there's a first for everything, especially when I have nothing to lose now that there is a new green lawnmower in my garage. I'll let you know what I find. When you stop learning, you stop living. My personal motto.
 

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That's how I learned. Daughter hit a metal pipe and broke the connecting rod. All in all, a very simple process, as HDNewf says. You'll not be disappointed.

10-12 years ago I had a LB that was so carboned up it scored the piston and cylinder walls. Fellow gave it to me. I tore it all apart, cleaned all the carbon out, steel wooled the piston, honed the rough edges off the gouges in the cylinder, put everything back together. No reason it should have run when I pulled the starter cord, but it did. Ended up giving to my brother. He asked me this spring if I wanted it back, as he was going to get a lawn service to do his yard. Still running great, best mower he ever had.....
 
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