Why is my Branson running rough?

Felix · Sep 2, 2010

I have a 3510 that I bought in 2003. It was running well until this past June when I had some kinda mishap that ended up with a hole in one of my rear tires leaking windshield wiper fluid all over. I got the tire fixed but had trouble getting the tractor started again. My local dealer came out and got it to start for me while I was at work (those guys are awesome), but now it runs REALLY rough. It will start up immediately and seems quite normal for about 20 seconds but then the revolutions drop substantially and seems like the tractor is going to cut off...but it never does. After about 30 seconds the revolutions will speed up and seems normal but then drops down again. The engine repeats this for as long as I leave the tractor running. If I try to move the tractor, it has no power and acts like it is going to stall. Again though, the tractor does NOT cut off.

Not sure to suspect the diesel fuel or something else. Any ideas?

MicroPilot · Sep 2, 2010

See this thread: http://www.tractorbynet.com/forums/zetor-century-branson/175007-2535-issue.html

Basically its probably an issue with the fuel cut off valve/fuel filter.

DavesTractor · Sep 3, 2010

Felix said:
I have a 3510 that I bought in 2003. It was running well until this past June when I had some kinda mishap that ended up with a hole in one of my rear tires leaking windshield wiper fluid all over. I got the tire fixed but had trouble getting the tractor started again. My local dealer came out and got it to start for me while I was at work (those guys are awesome), but now it runs REALLY rough. It will start up immediately and seems quite normal for about 20 seconds but then the revolutions drop substantially and seems like the tractor is going to cut off...but it never does. After about 30 seconds the revolutions will speed up and seems normal but then drops down again. The engine repeats this for as long as I leave the tractor running. If I try to move the tractor, it has no power and acts like it is going to stall. Again though, the tractor does NOT cut off.

Not sure to suspect the diesel fuel or something else. Any ideas?

Could be bad fuel, but more likely a clogged filter, clogged line, or the lift pump on the firewall stopped working. The lift pump is before the filter, so we have seen them get clogged with junk and they quit pumping.

Felix · Sep 4, 2010

Thanks Micropilot and Dave's Tractor. I start with your suggestions this weekend!

jgreen · Sep 8, 2010

Check for fuel in the fuel filter bowl. If none is present check fuel pump pressure of the electric pump (sometimes called the lift pump). I am not sure the exact spec. but I think it is 2-4 psi from the electric pump mounted on the firewall. You can check the pressure with a old style fuel pump pressure gauge like we used in the old carburetor/mechancial type fuel pumps. Most automotive vacuum test gauges have the ability to test low pressure fuel pumps. The electric pumps operate on a plunger action with a check valve. If no fuel pressure, you can take the electric pump apart by removing the three small screws holding the pump together (kind of a pain). Inside there is a o-ring, plastic plunger, spring and check valve. I had a piece of plastic from my tank lodge in the plunger and it would not pickup fuel from the tank. Do not remove the two screws on the black connector on top of the pump there is nothing serviceable in that area. Clean any debris and reassemble.

I posted this back on 4/7/09 but I thought it might be worth revisiting if it will help!

Thanks,

J. Green