time of running doesnt seem to matter. just restarting after first cold start. does not seem to matter if it is 5 minutes or 30 minutes. glow plug light comes on and goes off quickly cold or hot - but as i understand these plugs were some type of fast cycle units. i have not replaced them yet, but it seems to be more of being fuel starved than anything. how would i check fuel shutoff lever's operation? and i forgot to mention in initial post, the timing chain does not have play - it all seemed to be in very good condition. thanks