D902 engine problem?

[Plowman]

Hey guys we sell Toro out front mowers at work that are powered by Kubota D 902 engines and one came in last week with something going on that we can't put our finger on and I don't want to start tearing into something I am not familiar with.
We have never had one act like this.

Starts and runs fine, you start mowing and after about 10 min it starts to bog down and then dumps a hole bunch of smoke out of the exhaust? I mean like a steam train is following you......also it seems to rev up like the governor on a gas engine is failing? And then runs fine for about another 5min and then smoke again.

I know the smoke is due to a ton of fuel getting dumped into the cylinder, but what is the cause? Injector or injector pump?

Who rebuilds pumps if that is where we are going?

Thanks
Matt

 

[85Hokie]

Hey guys we sell Toro out front mowers at work that are powered by Kubota D 902 engines and one came in last week with something going on that we can't put our finger on and I don't want to start tearing into something I am not familiar with.
We have never had one act like this.

Starts and runs fine, you start mowing and after about 10 min it starts to bog down and then dumps a hole bunch of smoke out of the exhaust? I mean like a steam train is following you......also it seems to rev up like the governor on a gas engine is failing? And then runs fine for about another 5min and then smoke again.

I know the smoke is due to a ton of fuel getting dumped into the cylinder, but what is the cause? Injector or injector pump?

Who rebuilds pumps if that is where we are going?

Thanks
Matt

Not a diesel mechanic by no means here,

but - I will look at all the fuel filters, replace all the fuel, run a compression check.

What happens IF you let it idle of 20 minutes? Does it still do it? Is it a work hard at high revs thing? How many hours on the engine? Everything I am mentioning is a reach, you mention the governor, is it possible to "watch" it as you rev it up for an amount of time?

I think I would check all filters,
Check air filter,
Place new fuel in tank,
Start, allow a minute,
rev up - and let it sit for 10 + minutes.....

the fact that it starts messing up , then clears up has me scratching my head......

someone else will pop in here and have a better suggestion......

 

[Daren Todd]

I agree. I got a bunch of light towers with the d905 engines in them. Usually when they start running the way you described it's a fuel or filter issue. I use a water detecting paste to check the fuel tanks for water since the light towers have a 30 gallon tank. Could be a fuel cap not venting properly. Definitely rule out the simple and cheap stuff first.

 

[Plowman]

I agree. I got a bunch of light towers with the d905 engines in them. Usually when they start running the way you described it's a fuel or filter issue. I use a water detecting paste to check the fuel tanks for water since the light towers have a 30 gallon tank. Could be a fuel cap not venting properly. Definitely rule out the simple and cheap stuff first.

Thanks Guys for the all of the sugestions...
I will change the 2 inline fuel filters that kubota uses...the mowers have duel fender tanks and the way that they are shaped you cant get to the front bottom where the fuel fittings are.....with paste. When I ran it today in our test field, 20 passes back and forth about 200 feet each .....it started to bogg down and stall, I looked back behind me and I could not believe the smoke....that it was pushing out the exaust pipe... I let off the drive levers and it cleared up and I continued to cut but 5 min it did it again so I quit before I damaged somthing.

Will up date tomorrow.

 

[ehenry]

I've got a BX22 with the dame engine that has done what you describe a number of different times. Every time it was fuel related typically water in the fuel. I was using fuel from an old farm tank. I drained the tractors fuel tank completely, changed all filters and now only use store bought pump fuel and havent had a problem since.

 

[ShaunRH]

Yes, you could be seeing steam, not smoke, or a combination of the two since water would kill combustion efficiency resulting in unburned fuel.

 

[North Idaho Wolfman]

What color was the smoke?
Does it have a temp gauge?
Have you checked the radiator?