Good friend just gave me a non-running LB 7628. Mower appears to be complete and actually looks pretty good. I have cleaned muffler and ports, carburetor and checked for spark (yes, though it lt looked a little weak to me). Rough compression check yielded 25-30 psi and correlated to puny pull resistance with recoil rope. So, where to check next? Seals? Rings? Reeds? I am a reasonably competent shade tree mechanic with adequate tools, although unfamiliar with 2-stroke. I am up to tearing the engine down. Any thoughts, ideas, parts sources, etc., would be appreciated. I would like to get this green beauty up and running!
With that low of a compression, I doubt it will start. I'm not sure what engine you have, but parts for Lawn-Boy engines older than the Duraforce are getting hard to come by. You're probably looking at a new piston, rings and cylinder to get the compression up to a point it will start.
Yep, Jeff nailed it. The compression is way below the minimum. The engine is an F series. It probably will need a cylinder hone and rings at a minimum. Aftermarket piston and rings should be still available, but not positive on that.
#4
2smoked
There are a lot of Lawn Boys of this style still around, at least where I live. I worked on a 7268 last summer that had a trashed motor and was able to obtain a good donor motor for free. Now I know that this doesn’t happen for everyone, but you may be able to find a cheap donor mower somewhere with a good F motor. I am a believer in the F motor because with decent care, it was durable and long lasting. The one I worked on runs great—in fact, I plan on using it today to cut a very overgrown ditch ditch for an elderly couple. The old F motor is tough as nails.
Piston and rings are available on e-bay if you decide to go that route.You may as well replace seals too..Good luck with the project! Lawn-Boys are fairly easy to work on.
Manual with lots of info: https://lookup3.toro.com/ttcgateway/acrobat/manuals/lball.html
On my newly acquired 7268, I've decided to do a partial rebuild, i.e., new a/m piston, rings and seals. Total cost so far is about $26. All parts are in--now just need to make room on the work bench. With my wife out of town for couple of weeks, now is the time.
