Webasto Air Top Evo 40 - suddenly very smoky

[bozlite]

Had an Air Top Evo 40 installed fairly recently. I gave it a long run to test about a month ago and everything was fine. I tried it again today and it is belching out a lot of grey smoke. The exhaust seems to be clear (I could blow down it without much resistance, if that's any sort of test?) and I detached the combustion air intake hose to see if there was an obstruction there - doesn't seem to be. However, diesel is leaking back through the combustion air intake - what could that mean? Also, the air intake has a cable coming through it - which just doesn't look right to me. Pictures below. The first shows the air intake, with hose detached, showing cable coming through. The second is an attempt at an overview. Anyone got any ideas?

 

[David2452]

Don't worry about the cable exiting the air intake stub, that's the dosing pump lead and that's where many exit, make sure you tuck it back in the little slot before replacing the silencer. As for the grey smoke then a little more info is required, grey / white smoke is incomplete combustion, does it actually start and continue to run or shut down after a minute or so, could be over dosing or you could have excess fuel built up if the tank take off is high and you have no shut off valve in which case a decent hard run should clear it.
I hessitate to suggest coking as it's a new model 4.0 so can't have been used that much yet, mind you it will be under a three year on board warranty so just call out your local Webo agent.

 

[bozlite]

Don't worry about the cable exiting the air intake stub, that's the dosing pump lead and that's where many exit, make sure you tuck it back in the little slot before replacing the silencer. As for the grey smoke then a little more info is required, grey / white smoke is incomplete combustion, does it actually start and continue to run or shut down after a minute or so, could be over dosing or you could have excess fuel built up if the tank take off is high and you have no shut off valve in which case a decent hard run should clear it.
I hessitate to suggest coking as it's a new model 4.0 so can't have been used that much yet, mind you it will be under a three year on board warranty so just call out your local Webo agent.

Thanks for the quick response, David. The heater did cut out when I first started it, but I hadn't the smoke at that point. It restarted OK and it was then that I noticed the smoke. Quite a dark grey smoke, and there was some oily soot in the exhaust (which I could see on the water). Worth giving it a hard run, do you think?

Thanks again.

 

[David2452]

Worth giving it a hard run, do you think?

Absolutely, but even if the smoke clears I would talk to the installing agent.