Well, I managed to copy an old thread of mine here, but erased everything I said in a reply to your post. Won't do it over, just check this old thread and decide if you were saying you almost broke the rope trying to pull it through the compression stroke, or if it was snatching back on you before you could finish the pull. You didn't mention if the "dead battery" was weak and couldn't roll on through the compression stroke or not. You pulled on the rope in its place. Read on, let us know about a comparison pull between when the motor's fully warmed up, and an identical pull when it's cooled down.
I've read many posts and seen videos about people nearly getting fingers broken by the violent "snatchback" of pullropes. Experienced some of that myself on hotrodded Predator 212 @ 12 hp., and recently with my current 212 @ 15+ hp.
Many people have automatically thought about there being excessive timing advance when that happens. I myself went to the flywheel, looking for a broken advance key spinning the wheel, or anything else obvious. The 28 degree PVL flywheel got a #6 advance key, which was still okay. I put the OEM key (no advance) back in, so just 28 degrees total when trying again.
Still snatching back, but then I lost my balance yanking on it, stumbled backwards, and saw a bunch more rope come out. Had been pulling far enough to get through a full cycle, about 3'. The snatchback always was right at the end of that.
Measured my pullrope and found there's "51" of rope there to pull on! Purposely stepped back a bit from the motor to make room, yanked a full 4', and it hasn't snatched back on me since! As long as I don't allow the pull to stop at just 3', the motor fires forward instead of backward.
So when you're pulling, step back and force a nonstop longer pull.
