Sputtering and losing power after 20-30 minutes

gerytb · Feb 18, 2015

I have a diesel mahindra 4035. Every time I use the tractor, after 20 or 30 minutes it starts to sputter adn lose power. it blows a puff of black smoke followed by continuous, but not like a fog of blue smoke. I can take it back to idle and it idles fine, but if I try to take the RPMs up again it sputters around 1500 to 1800. In the summer months when it started to sputter, it did so, but cleared up after 15 seconds. Now in colder weather it does not recover. In October, the dealer told me it was an SBJ unit??? some kind of device that changed the timing of the injector pump. They adjusted it, and it quit the sputtering. Now in cold weather it is worse. The dealer, based on a conversation with the factory, said that it may be the fuel cap not venting or some kind of internal leak in a diaphram? I assume they mean the fuel pump. They want to put old fuel lines on with clear tubing to check for bubbles. Anyway, does anyone have any experience with this? As far as i ever knew, black smoke was too much fuel, and blue smoke always meant engine oil being burned. Help! Anyone.

Tx Jim · Feb 19, 2015

Have you checked for "good fuel flow" from tank to inj pump????????????

danfromsyr · Feb 20, 2015

in my kubota it's the water in the fuel filter expanding and restricting fuel flow.
I'm not familiar with your tractor or fuel filter but in mine it has a felt membrane that allows fuel (oily) to pass thru but stops water (won't pass thru oily felt) till the temps make slush and it chokes off fuel.
it doesn't look like a special fuel filter, but it is.. also there were (2) so make sure you don't have a hidden one someplace.
fuel for thought that's all.

oldpilgrim · Feb 20, 2015

take off the fuel cap and try running it that way to try and duplicate the problem. Start with the easy, cheap stuff first.

PILOON · Feb 20, 2015

Sounds like your fuel is gelling up.
Do you use an additive for gelling?
Air intake blocked?
Like said 20-30 mins could suggest cap vent blocked. Run it without the cap on to prove that option.

BXman98 · Mar 18, 2015

It sounds like it could be fuel gelling as well, i have the same problem with my Kubota BX2370 during the winter months.

RalphVa · Mar 19, 2015

I'd check for wax globs partly plugging off fuel flow at the outlet of your fuel tank. Wax globs can form, especially if you've used fuel with a little bit of bio, during cold nights in the winter. Could have happened last winter. It would have to get pretty warm to melt them during the summer.

You'll have to siphon the tank and shine a light and hopefully see where the outlet line is out of the tank from inside. Then you need to either fish the wax globs out or melt them with very hot (around 150 F) kerosene.

This happened to me on my JD 4010 4 or 5 winters ago.

Ralph

woodchipper · Mar 19, 2015

Again, simple thing to check, already mentioned. Your air filter could be dirty/cloged. Your air passage way could be cloged as well. Black smoke is an indicator of that. As well your fuel filters could be full of water and sediments. Remove and clean thoroughly. Ensure the bottom of the fuel tank is clean, and free from heavy deposits, and ice. If all those suggestions are done and you have no improvement, then I would check for a dirt/debris corrupted injection pump.

jjlite · Mar 19, 2015

look through the Mahindra Owning and Operating Archives and you will find a lot on this subject. My 4035 did this exact things you describe. I had a loose wire on injection pump fuel solenoid, also out of time had the injection pump turned a little also had trash in the tank drill shavings and a piece of plastic bag. I found the trash in the tank by taking off the fuel line going to the filter and saw black shavings in the top of the filter housing and down in the line I cleaned them out with a pick and blew some air back into the tank it cured the problems for a while but I ended up draining the tank and using a shop vac ran through a five gallon bucket to catch anything coming from the tank. The piece of plastic bag was also up in the top of the filter housing. All thanks to members on TBN my tractors been fine ever since Oh and my dealer helped some to. I would really check out the connections on your injection pump mine had same smoke Black to grey. Good Luck!