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I bought a used x750 (diesel). When I start it (even when it's hot outside) the muffler blows a dark smoke for about 30 seconds each time I start it. Is it supposed to do this?
 

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It is common for a diesel to emit dark exhaust for a few seconds when started. 30-seconds seems like a long time though.
 

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My x758 doesn't do that. Maybe a quick puff immediately as it starts but that's all.

Rob
 

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Black smoke is too much fuel and or poor combustion.

Check the simple stuff air filter, fuel filters, oil change, good quality clean fuel in the tank, possibly add some fuel additive to help clean up any built up carbon. You may have a slightly fouled injector tip or the like.

Depending on just how used your tractor is and how well it was maintained you may also have low compression which is more noticable when the engine is cold. There could also be a fouled injector tip which could lead to poor combustion with a cold engine.
 

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Could be a couple of things,not enough air check the filter and intake for nest if it sat for awhile. Faulty injector can cause the problem.
 

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Maybe the prior owner like rolling coal so he put a tuner on it...
 

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Just to cover the bases, are you waiting for the glow plug light to go out before cranking the engine?

Sent from my SM-G900R4 using Tapatalk
 

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Should I be starting this at full idle?

I do wait for the glow plug light to shut off.
I always start my x758 at lowest throttle position. Never a need to do otherwise. That's how I start pretty much every engine, except my old JD 345 which required the throttle to be at max in order for the choke to kick in. That always baffled me why they designed it like that. Several years after my 345 model year they separated the controls.

Rob
 

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I thought the instructions in the manual say to start it at mid throttle?
Anyways at least in my case I wait for the glow plug light to go out and start and a tiny puff like the others

My bet is exactly what the guys above said
Poor fuel, dirty filter etc I’d check all that
 

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I thought the instructions in the manual say to start it at mid throttle?
It does. But I see no reason for it. Never been a fan of high RPMs at startup. That's when an engine is most prone to internal wear because oil has drained away and needs to be pumped back around. No perceived value/benefit and a potential for harm means I start engines as low throttle as possible.

Rob
 
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