Small Diesel Generator Smoke On Startup

[Lewis]

Hi all, I've just got a small diesel generator 5-6KW with a 400CC Yanmar L100N air cooled diesel engine inside. When I start it up it will give a puff of black smoke until it is up to speed then it runs clear as you can see in the video. Is this normal or should I be worried about it ?

Video: https://youtu.be/4QJHOLYqeTw

 

[JTK]

That's nothing in terms of cold start smoke for a little diesel like that. Cool generator!

 

[JohnnyJohnson]

I wouldn't worry about it. Lots of diesels do that on start up.

 

[Lyman]

We maintain military diesel generators where I work. Every single one of them does the same. It's normal.

 

[Kamele0N]

That is 105% normal for a diesel without a DPF filter...

 

[Donald]

Only the new diesels with lots of pollution control stuff don't smoke at startup.

Does your have glow plugs?

 

[Lewis]

No glowplugs or intake heater, in fact apart from the starter motor there is nothing electrical on the engine.

 

[Chris142]

Normal. It takes a few revolutions to get up to speed. Things neat! How much fuel does it consume?

 

[Trav]

Cool little generator, the smoke at start is totally normal, no worries.

 

[The_Jeff]

There's something about governing diesel engines that basically overfuels them until they "catch up". Avoiding this is complicated.

This was apparently an issue with the first Alco diesel locomotives, leading to a trademark black cloud until they were up to speed.

 

[JTK]

Originally Posted by eljefino
There's something about governing diesel engines that basically overfuels them until they "catch up". Avoiding this is complicated.

This was apparently an issue with the first Alco diesel locomotives, leading to a trademark black cloud until they were up to speed.



It's the same with even a modern day huge stationary diesel gen set. Occasionally we have to rent them for components at the plant. Like you say, the governors peg wide open until the engine RPMs come up on the cold engine. Sometimes oscillating full/closed/full/closed a few times. Talk about a smoke show!

In terms of the OPs little diesel gen set, The bigger gasoline powered ones, especially if it's a Kohler or Briggs V-twin can smoke more than that on a cold start.

 

[Cujet]

The fuel pump/injection system is is at the max open position at zero RPM. They will modulate only when rated RPM is achieved. Hence the overfueling and black smoke.

 

[tig1]

No problem.

 

[BigShug681]

Nothing to worry about my 6.0 diesel truck looked like a steam engine for a good minute this morning, coldest cold start I've ever done was today as well oil temp registered at 6F.