Smoke out of Air Filter [Perkins 4.108]

[BigAl.NZ]

Hi all,

This evening after a routine run of the engine I noticed white smoke coming out of the air filter on the Perkins 4.108.

Here is a two videos and a photo:

https://photos.app.goo.gl/qGjcEh8tTneH8MvJ9

What could this be a sign of?

[skipperpete]

Originally Posted by BigAl.NZ

Hi all,



This evening after a routine run of the engine I noticed white smoke coming out of the air filter on the Perkins 4.108.



Here is a two videos and a photo:



https://photos.app.goo.gl/qGjcEh8tTneH8MvJ9



What could this be a sign of?

Hi BigAl.NZ
It looks like the coldstart is activated, disconnect the large spade terminal on the air intake and see if that stops it.

[BigAl.NZ]

Thanks - will check that when I am next on the boat. BTW - what is cold start exactly? Someone else suggested it was just "vapor" but it seemed to last too long and seemed to have a slight smell to it. Never noticed it before...

[skipperpete]

Originally Posted by BigAl.NZ

Thanks - will check that when I am next on the boat. BTW - what is cold start exactly? Someone else suggested it was just "vapor" but it seemed to last too long and seemed to have a slight smell to it. Never noticed it before...

The cold start consists of a heating element just inside the intake manifold and a fuel line that allows raw diesel to drip onto the element when it's activated. It draws a lot of power and will set the fuel on fire so should only be used while actually cranking the engine. You may have an electrical problem that's causing the heater to be activated uncommanded.

[Lepke]

The air filter isn't stock. Make sure it doesn't restrict incoming air. I don't think it's big enough. Most diesel marine engines, especially big ones only use screens because they're not run in a dusty environment.
The engine doesn't know there is a restriction, so gives the normal amount of fuel and the charge is unbalanced. In the long run air restriction can hurt the engine and it's not fuel efficient.

[BruceS]

Yep, it's the cold start. Either it is electrically activated as said or it's stuck open and allowing diesel to enter the inlet.
When activated on a very cold start, as it heats up it opens similar to a thermostat and allows fuel through. If you never use it then maybe remove it. Many in Australia come without one at all. We don't get freezing conditions at sea level.... much.