Hello,

Having some trouble with this forklift. It's given us many years of good usage.

Problems:

#1. Cylinders 2 & 3 foul plugs bad. in just an hour black dark dry soot covers the plugs. Cylinders 1 & 4 look perfect.

#2. Will not run on propane. Only on gasoline. Used to run on Propane beautifully for years. Just this year, it refuses. (Dies)

Compression test 150psi+ on all cylinders.
Changed plugs to brand new autolite 66
Cleaned air filter
New coil and wires as well.
Had carb rebuilt 2+ years ago by a local mechanic. Worked well after he did.

Engine runs pretty well, some "pop pop" in the exhaust from time to time. Not as much power as I'd like, but it's a 9K forklite with a small 4 cylinder so that might be normal.

So other than replacing the carb, can anyone offer some advice as to why 2 cyclinders would run so different from the outers? (The intake is a siamese type. so #1 and 2 are feed off the same port and #3 and 4 off the other.)