Kubota RTV 900 Won't Start After Piston Replacement - Just puffs Smoke

[CollinDe]

Hey Guys, hope all is well. So after replacing piston number 2 after the engine over heated and I got everything back together. All I seem to get is a little white smoke out of the exhaust when I crank it over but no fire. I have bled the fuel lines twice at the injector till they all had fuel coming out of them and still nothing. The second time I did this it seemed to rumble a few times like it almost wanted to start but didn't. Just a bit more white smoke is all I got.

When the engine was apart there was no scoring on the cylinder walls which were honed, just stuck rings on the centre piston. I replaced both sets of rings on the outer pistons and put a new piston in the middle. The head looked fine as well so no work was done to that. It did run 5 months ago before I did the work which I just finished yesterday. Engine was only open three weeks and I did not have to pull the engine out either. So there was very little to disconnect. So I am a bit confused as to why it won't start now.

Any idea's, please.

 

[pmsmechanic]

Try bleeding the fuel lines again. Sometimes you don't get all the air out the first time. Also the rings aren't seated yet so there might not be enough compression to ignite the diesel fuel. Is there any way you can warm the engine up as that would probably help? If it has a block heater plug that in. Blow with a hair dryer down the intake manifold on the engine to warm that up.

 

[kuboman]

Are the glow plugs operating?

 

[truckdiagnostics]

Don't panic they are hard to get bleed. the kubota in our loader has a thumb screw on the pump where the return lines come together, now i have a bleeder ball on the suction line that we pump, squeezing the bulb and with that screw open you can see fuel at the return line. Don't forget the simple stuff, shut off opening ect., if you can replace a piston you should have that down. don't mean to insult your intelligence.

 

[kuboman]

If you are getting white smoke you are getting fuel. White smoke indicates low compression which is understandable with all new rings. If your glow plugs are working then you need to preheat the engine to get it to fire up. You must be sure the glow plugs are working otherwise it will take a while to get it to fire.

 

[valkyrie9901]

Did you stagger the rings on assembly?

 

[CollinDe]

Did you stagger the rings on assembly?

Hi and Thanks guys. It did fire up last night, lots of white smoke at the start and it slowly got better. Hardly anything comes out. Yes rings are stagerd, The engine got very hot though after 15 min, rad was cold but engine hot. I think the thermostat is stuck and am going to change that. Might of found why it over heated in the first place, am I right?

 

[valkyrie9901]

Would replace it any ways on a re-build.....JB.

 

[sunnyside360]

Hi and Thanks guys. It did fire up last night, lots of white smoke at the start and it slowly got better. Hardly anything comes out. Yes rings are stagerd, The engine got very hot though after 15 min, rad was cold but engine hot. I think the thermostat is stuck and am going to change that. Might of found why it over heated in the first place, am I right?

Most likely the thermostat is not working. Sometimes they get stuck open in which case the engine doesn't come up to temperature and sometimes they get stuck closed in which case the engine over heats. Have seen many of both cases. Depending on how old the coolant is you may want to change it while you are into the coolant system (see Operators Manual).

 

[pmsmechanic]

Infrared thermometers aren't that expensive any more and if you hold the beam on the thermostat housing it's very easy to see when the thermostat opens and closes. Saves taking the thermostat out if there is nothing wrong with it.