Hi All,

Our local feed store has a forklift that has never run very well since they purchased it (low power, barely makes it up slight incline). He had a diesel mechanic do a tune up on it (plugs, cap, rotor, points...). He was still having trouble so I offered to rebuild the carb (Zenith). I assumed the other mechanic had at least troubleshooted the motor a little bit, but unfortunately I didn't check the motor out before rebuilding the carb and when I put the carb back on it still ran almost as bad. I did the one spark plug wire off at a time trick and the 3rd cylinder is dead. I pulled the plug and checked the spark and it is fine.

I left a message for the owner to call me because I wanted to tell him he had a dead cylinder. Instead he had another mechanic come to look at it when he couldn't get started one morning (after using it several times since I rebuilt the carb). I happened to come by while he was doing a compression test and the dead cylinder (to my surprise) had the best compression of all 4 cylinders??? I told him about the dead cylinder and he was still trying to blaim the carb, typical.

The fact that it has good compression and spark sorta has me stumped. I didn't do the compression test myself, so maybe that cylinder took longer to come up to pressure, but it seems odd.

Why would a cylinder with good spark and good compression not fire? I've never worked on a flathead and I looked but couldn't find any access to check the valve adjustment, is there one? Could the intake valve not be opening all the way? What could cause this?

He's been using his bobcat to unload the trucks, but it's been bugging me and I'd like to fix it for him if I can. Thanks.

Sven