Kubota v1702 hard start and black smoke

[gladiatore]

Hi guys long time i didnt post here, i have a problem with a kubota engine v1702, for start it takes centuries, and blows a lot A LOT of black smoke, after it starts is ok but first start is a really pain, i already sent 3 times starter to get fixed because becomes so hot parts unweld inside, i changed fuel filter, no air in lines, new spark plugs (i left them 10 secs every try to start) fuel injectors are opening arround 2800 to 3000 psi, what it could be?

 

[Delmer]

Does it run GOOD when it's all warmed up and running? When it starts does it take a minute to run smooth? Is the black smoke when it's trying to start, or when it's running under load? Have you checked the resistance of the glow plugs, and that they're getting power when they should? Any crankcase blowby? And last, but not least, what is this engine in, is there any drag on it?

 

[gladiatore]

ok answering.

when hot runs and starts smooth,
somethimes looks like when start need a bit of time to start run good (not all time only in first start and not always, sometimes it starts good even was hard for start)
black smoke only in the first cold start A LOT
glow plugs working great (was a problem before didnt had electricity i did direct from a battery and even like that took centuries start)
under work is normal black smoke under load
no strange sounds of engine when working
i just mounted in a case uniloader, before was in a bobcat, same problems for start also when was mounted in bobcat

 

[gladiatore]

also i want ask how much time should i put preheaters so i dont burn them

 

[Delmer]

Ten seconds should be enough on the glow plugs.

It still sounds like glow plugs.

Otherwise low compression would do it. Or injection timing, hard to mess up the timing on a Kubota, but anything's possible if somebody has taken it apart.

Somebody else here was having starting problems with an aftermarket cylinder head on a Kubota, I don't think I saw the result of that one.

 

[gladiatore]

btw i just made a service to head, and is not aftermarket, raplaced all valvles and seats, is perfect, in that part about head
1

 

[crewchief888]

is the hard starting something that recently started happening, or has it been that way all the time?

if the 1702 is the engine i think it is, (they were used in bobcat skid steer's back in the 80's), they were notorious hard starting engines, always needed a LOT of glow plug to fire up. even in warm, sunny florida 10-15 seconds was recommended. colder ambient air temps need longer glow plug cycles, i gone as long as a couple minutes,(sometimes even longer) in 10F weather.

since you already had the head off, is this a direct injected or indirect injected engine?


:drinkup

 

[Welder Dave]

A V1702(B) is indirect injection. I have V1902B which is the bigger brother but virtually the same. They need glow plugs for 10 seconds or so on the first start even if it is 80 deg's outside. I have a glow plug indicator and when it's cold sometimes you do need the glow plugs for a couple minutes. There is a video online of a dealer showing how to start a Kubota tractor and says it doesn't hurt to leave the glow plugs on longer. Also put it to full throttle to start when it's cold out and slow it down after it starts. Huge difference between starting and not starting. Even plugged in with a block heater and hyd. heater my machine can be a pain to get going when it's -25/-30C. The later V1903 engines were direct injection and much easier to start. One other thing, NEVER use ether on a Kubota. They are a very good engine and a mechanic told me the tolerances are so close in them that ether will destroy them.