ZD28 sputtering/ power loss

[Pmschmitt]

Ok I bought a ZD28 with a bad hydro about 6 months ago and rebuilt the hydro system on the machine. Machine had 640hrs. When I rebuilt the hydro I did not clean out the fuel tank. ( dumb looking back) It had been sitting for some period of time before my purchase. After getting it all back together the machine ran great several times. The third time it started to sputter and lose power after mowing an hour. I limped it back to garage and checked fuel filters they seemed dirty. I replaced them and checked the fuel flow and it seemed to improve. The machine ran well another couple times but now is doing it again. The filters looked clean but I went to investigate further. I replaced the filters but the pump only seemed to have a trickle coming out. Even with new filters Also when disconnecting tank line to first filter (under motor) there was only a trickle of diesel coming out hose not great flow. The other thing that’s weird is the fuel pump never cuts off.... isn’t it supposed to cut off once pressure is primed? Also the second fuel filter before the pump only seems to be half full and always has air in it. Could the fuel pump be sucking air in? Cracked hose etc?

I replaced the fuel pump and it didn’t change a thing. I also cleaned the fuse block, replaced fuses and checked connections on batters they are all tight. No improvement.

My thoughts are replacing all the fuel lines and cleaning the tank?

Also the electrical safety stuff on this mower has been bypassed it has to be jumped at starter to start but it fires right up. Just loses power under load when “bouncing” around mowing. It never dies just stumbles and stutters. It is super annoying.

All help appreciated.
Paul

 

[D2Cat]

Maybe you have an algae farm in the fuel tank. Sounds like a fuel problem of some sort, and it's probably before the filters. Drain the tank and see what you come up with.... water, filth, slime, leaves?

 

[Dave_eng]

Your comment "just loses power under load when “bouncing” around mowing. It never dies just stumbles and stutters. It is super annoying." makes me wonder if the seat switch is involved with the bouncing intermitently triggering a safety.

Does it do the same thing is the mower is not engaged?

Dave

 

[thepumpguysc]

Your statement about pulling the 1st hose & a trickle tells me u have a fuel tank blockage..
Wait till u get low of fuel & pull the entire fitting out of the bottom of the tank..
You'll def. find your problem..
Good luck & let us know.

 

[whitetiger]

A ZD28 draws fuel from a tube inserted through the top of the tank and they do not have a drain on the bottom. Remove the hose on inlet side of the first fuel filter and remove fuel fill cap. Shoot a blast of compressed air into the hose which will clear the suction tube in the tank. Put the hose back onto the fuel filter and turn on the key to run the electric lift pump. If you now have a good stream of fuel out of the second filter, remove and clean your fuel tank.

I probably clean out 20 or more units a year.

 

[ZD326S]

I disconnected the gas line at the off/right/left tank valve and used a hand siphoning pump and pulled the blockage out! My sputtering was eliminated.

 

[Otto1440]

Ok I bought a ZD28 with a bad hydro about 6 months ago and rebuilt the hydro system on the machine. Machine had 640hrs. When I rebuilt the hydro I did not clean out the fuel tank. ( dumb looking back) It had been sitting for some period of time before my purchase. After getting it all back together the machine ran great several times. The third time it started to sputter and lose power after mowing an hour. I limped it back to garage and checked fuel filters they seemed dirty. I replaced them and checked the fuel flow and it seemed to improve. The machine ran well another couple times but now is doing it again. The filters looked clean but I went to investigate further. I replaced the filters but the pump only seemed to have a trickle coming out. Even with new filters Also when disconnecting tank line to first filter (under motor) there was only a trickle of diesel coming out hose not great flow. The other thing that’s weird is the fuel pump never cuts off.... isn’t it supposed to cut off once pressure is primed? Also the second fuel filter before the pump only seems to be half full and always has air in it. Could the fuel pump be sucking air in? Cracked hose etc?

I replaced the fuel pump and it didn’t change a thing. I also cleaned the fuse block, replaced fuses and checked connections on batters they are all tight. No improvement.

My thoughts are replacing all the fuel lines and cleaning the tank?

Also the electrical safety stuff on this mower has been bypassed it has to be jumped at starter to start but it fires right up. Just loses power under load when “bouncing” around mowing. It never dies just stumbles and stutters. It is super annoying.

All help appreciated.
Paul

We have been dealing with this problem for 5 years on our ZD21 F and after changing filters every time, we finally decided to look for other problems and ran across this post. We removed the ROP, the fender, the hoses, and the tank. We emptied the tank and found a nozzle from a gas can, but did not stop there. We blew out the tank and every orfice, put new filters on even though we had just changed them about a week before, cut and replaced all fuel lines, reassembled mower, put in fresh fuel and started. After a minute, I knew something was different. The mower seemed to have more power and after mowing for forty minutes it was still good to go. Usually after 15-20 minutes it started to sputter out. Thanks to this forum and especially Paul, I have faith again in my almost 20 year old machine. The only problem that we had was the ROP and that was putting the thing back on.
It is heavy.