I have a 4960 that used to start great but now won't start unless it's plugged in or over 50 degrees. The engine blew a head gasket last August after a head bolt snapped. I replaced the gasket and bolts and made sure the liners were good, they had great Cross hatch on them yet and there is no blow by at all. It was starting hard but I thought it was just the blown gasket because after it was replaced it got better for 2 months untill the weather turned. Like all 4k series when it started it would rev up and then settle at idle. It slowly started to loose that and now it won't do that at all it just cranks and cranks and then just idles.
I screwed the aneriod screw all the way in to gain a little more power up top which helped alot. I thought that had something to do with it so I screwed it back out but it didn't help. I'm thinking governor springs next, any ideas?
The shut-off valve is working correctly and the fuel filters were change 6 months ago when it all started. Now it won't reach full rpm either, it stops about 300 below top.