Another smokey engine question.......

[Brightside]

New (to me) boat of 10 years vintage with late'ish Yanmar engines of the the non electronic type. Engine was surveyed before purchase and since fully serviced by Yanmar specialist. Don't believe there are any issues including bore and the "smoke" clour I am told is correct. Boat has fsh and well maintained. However engine is still smokey at slow speeds in and around the marina and until up on the plane. Smoke does not seem to relate to time of running, but speed/revs which I suppose makes sense. I am (almost) resigned to living with this, unpleasant for neighbours on start up but also for the crew for too long! I recall reading of the "smokey non electronic injected engines" of which I definitely have two - but are there any options open to me. Retro-fit electronic injectors??? Fuel additives? Would welcome any ideas (and suggestions of cost). Previous boat had older engines - Perkins - which whilst of less power did not hit us with deisel smoke.

 

[Bbroomlea]

My KAD32's can be smokey on start up and at low revs until warm. When we bought the boat it had been brought back from Spain and was full to the brim of white diesel. The cold running smokieness only started when I topped up with red! It was almost as if someone had fitted two different engines at the same time as filling the fuel.

I now put a dose of Marine 16 Diesel fuel complete in each tank and again back to 'almost' clean running. It also contains diesel bug so get the best of both worlds!

 

[Momac]

How much fuel have you consumed?
Not unknown for a smokey engine to become less so after fresh fuel is added.

A fuel additive may help. I have used Marine 16 diesel fuel complete on my VP engines and feel it does result in cleaner running.

.

 

[Latestarter1]

New (to me) boat of 10 years vintage with late'ish Yanmar engines of the the non electronic type. Engine was surveyed before purchase and since fully serviced by Yanmar specialist. Don't believe there are any issues including bore and the "smoke" clour I am told is correct. Boat has fsh and well maintained. However engine is still smokey at slow speeds in and around the marina and until up on the plane. Smoke does not seem to relate to time of running, but speed/revs which I suppose makes sense. I am (almost) resigned to living with this, unpleasant for neighbours on start up but also for the crew for too long! I recall reading of the "smokey non electronic injected engines" of which I definitely have two - but are there any options open to me. Retro-fit electronic injectors??? Fuel additives? Would welcome any ideas (and suggestions of cost). Previous boat had older engines - Perkins - which whilst of less power did not hit us with deisel smoke.

'late'ish Yanmar' no chance WHATSOEVER of getting a meaningful answer whiteout any clue as to engine model and power rating...........................

 

[n.herring]

New (to me) boat of 10 years vintage with late'ish Yanmar engines of the the non electronic type. Engine was surveyed before purchase and since fully serviced by Yanmar specialist. Don't believe there are any issues including bore and the "smoke" clour I am told is correct. Boat has fsh and well maintained. However engine is still smokey at slow speeds in and around the marina and until up on the plane. Smoke does not seem to relate to time of running, but speed/revs which I suppose makes sense. I am (almost) resigned to living with this, unpleasant for neighbours on start up but also for the crew for too long! I recall reading of the "smokey non electronic injected engines" of which I definitely have two - but are there any options open to me. Retro-fit electronic injectors??? Fuel additives? Would welcome any ideas (and suggestions of cost). Previous boat had older engines - Perkins - which whilst of less power did not hit us with deisel smoke.

We had exactly the same problem, Barrus fitted pre heaters, problem solved. When these engines are sold in Norway and colder climates pre heaters are standard fitment.
Talk to Barrus I am sure they can sort it for you, Neil

 

[Brightside]

Sorry Latestarter1, Engines are Yanmar 6LPA-STP

 

[Brightside]

Hi Neil

Thank you for this suggestion, I will speak to Barrus. Any idea what I should be expecting cost wise? Please PM me if you would prefer not posting such info.

 

[Latestarter1]

Sorry Latestarter1, Engines are Yanmar 6LPA-STP

Many thanks.

Yanmar LP's are very sensitive to seawater ambient temperature. All LP's I came across in the U.S has air inlet grid heaters for smoke free start up, always assumed European spec were the same.

For smoke free part load operation your engines need to stay at thermostat opening temp or above which I believe is 68C (min) to 72C...Fully open 89C

Your problem is quite common with this engine at low seawater ambients and Yanmar should have developed a thermostat system that has a higher opening temp so coolant temps at low power settings stay above 82C, possibly something not totally on the radar when marinising an automotive base engine. I consider a 22C delta from closed to fully open too wide a range for a seawater after-cooled engine particularly one that uses seawater to cool the lube oil. What is probably happening is that that the piston cooling nozzles are shooting over cooled oil to the underside of the pistons cooling them down enough to exaggerate the white/grey smoke issue at low load.

Very good engine, shame Yanmar engineers never got a proper grip of the cooling system.

 

[Brightside]

Just a note to thank you for your replies. Appreciated. I will be trying the various options (costs permitting) in order of price and will let you know if there is a solution.

Again, thanks for the advice. Have a great Chritsmas and good boating in 2016.