L3540 losing power

[ddb123]

Was mowing today and noticed that the tractor wouldn't achieve much speed in M low or M high. RPMs would bog way down when peddle was pressed. Giving more throttle didn't help. In fact, tractor seemed slightly starved for fuel. Idle was around 500 RPMs rather than the usual 800 or so. Full throttle was about 2500 vs the usual 3000.

My first thought is the fuel filter, but wanted to check the hivemind and see what others think I should check. Tractor has never given me any problems other than this and only has about 200 hours.

 

[DK35vince]

Start by changing the fuel filter and checking the air filter.

 

[The Fred]

Black smoke under load would indicate the air filter is plugging as indicated by the filter minder device turning red.

No black smoke under load would indicate fuel starvation.

Regards, Fred

 

[ddb123]

No black smoke. Checked the air filters and they looked fine. Heading to the Kubota dealer today to pick up the fuel filter. Will update with progress. Thanks!

 

[Raw Dodge]

Definitely a plugged fuel filter or weak transfer fuel pump

 

[ddb123]

Went ahead and changed the fuel filter, although the old one looked brand new. Didn't help.

The problem appears to be worse than I originally thought. On fairly level ground, in M low, with PTO engaged (finish mower), RPMs at 2700, and not moving, pushing my foot slowly forward, tractor barely moves and a white or blue, almost invisible smoke emerges from the front. I believe it comes from the exhaust, which usually means unburnt fuel (I think) but this is much less blue. HST operation seems very jerky, that's how I initially noticed something wasn't right yesterday.

 

[C4Ranch]

Bad fuel?

How long has the tractor sat before you used last?

 

[ddb123]

Maybe a couple weeks. Full tank, from two different re-fills.

It acts like it's under serious load even when it's just rolling.

 

[ddb123]

Well, there is definitely something wrong with it. I thought maybe it was a transmission problem, so I just now ran it in and out of 4wd, through all the ranges, and at various throttles. The tractor seems to run more or less okay at 2000 RPMs or fewer, but at 2500 sitting still without the PTO, it spits out a lot of that thin, light smoke. Does NOT appear to be coming from the exhaust.

The engine also surges a bit at idle. Not enough to really appear on the tach, but enough to hear, at about one-second intervals. I usually wear earbuds when on the tractor, but the engine doesn't sound right, either.

 

[The Fred]

Still under warranty?

The fuel transfer pump might be on its way out.

Fred