While cutting the grass the other day my 170 felt a little sluggish on the slight uphill in my backyard and then it finally just quit. I was able to restart it immediately, but I quickly noticed that it would only run if fully choked or with the throttle all the way down at idle. Pushing the throttle just a hair above idle would kill it. My initial thought was that something was wrong with the throttle linkage-all of that is working properly. I pulled the line from the fuel pump to the carb and got a quick squirt of fuel with every crank of the engine. I see that there is a little fuel filter inline before the pump-could it be that the filter is clogged just enough that it will only flow enough fuel for idling? Does it sound like a carb problem? Prior to all of this I've never had a problem-in fact, prior to it become sluggish about 10 seconds before it died it was cutting like a champ as always. It has the Kawasaki 14HP engine-I got it from my FIL who got it new in 1988 or 1989. Any ideas?