[bob44319_318]

Hi guys,
I have a 91 430 with 1450 hrs on it. I was mowing tonight after work and my 430 started to lose power and was surging very erratic. I turned off the mower deck, and lowered the throttle and no change. Keep messing with the throttle and it finally started running smooth, then back to surging and no power. I shut it off thinking i was out of fuel, but i wasn't out but it was a little low. I put more fuel in it hoping not having to bleed the lines and it ran fine for a little bit until i turned on the pto and started moving forward.It started to lose power and surge. I limped it back to the house. I checked the fuel line in the tank and it was still intact then I bled the fuel system and got some air out. Started it ran smooth, then started surging then smooth again, so i let it run for 15 minutes trying to make sure to get the air out. It sputtered every once in a while but cleared right up. I then drove it a few feet and turned on the mower deck and it started to lose power again and surge. That is where i left off.
Tomorrow i am going to check the fuel pump for enough flow and bleed the fuel system again, check all clamps and fittings in the fuel system and see what happens. If its not the fuel pump and i get all the air out of the lines if any, I will probably look at the fuel injectors and possibly replace fuel lines even though they look good
Seems to me its a fuel issue. The fuel filter was replaced last spring and i would think its still good. There is no water in the fuel. Also i run stanadyne in my fuel.
Anyone else have any other ideas?

 

[coalminer16]

Filter can become plugged with the first tank of fuel depending on what is in the fuel so don't 100% rule that out. The fuel lines if not tight at the connections can suck air in before the pump or have a small pin hole. Or a line could be pinched.

Injectors aren't going to go back and forth like this. They tend to fail at the nozzles where the spray becomes a stream. Sometimes they can become sticky-but rarely will it go back and forther then.

 

[knottyrope]

line inside of tank could have fallen off or cracked

pull line from filter to inj pump and hold it 2 feet above tractor and see what flows in 30 seconds with key on

 

[hankvc]

Bob, have you pulled the fender deck and pulled out the fuel connections on the tank? If you haven't, you need to check that the pickup screen is clean and the hose inside the tank is not broken. Diesel tanks also want a good washout, even if they look clean inside.

Your symptoms are consistent with poor fuel delivery to the injector pump. If the lift pump stops running, the engine will continue to run, but will surge, smoke, and lose power, just as you describe.

Hank

 

[bob44319_318]

Guys,
thanks for the replies.
The checked the fuel connections in the tank and they were good. I replaced those last year. I tested the fuel delivery pump and the flow was in spec according to the manual.
I then checked all of the lines and fittings. then bled the system 2 more times and its running again and mowed for over an hour without any issues.
Thanks for all the help.
Bob