Diesel outboards

There is a considerable weight penalty, I believe the diesel outboards weigh around 400 Kg. On the bigger vessels they diesel OB’s are targeting the motor weight is a smaller % of the total vessel weight so it isn’t much of an issue. Same thing with the XTO when it came out and everyone said it will never work because it weighs 460 Kg. That’s clearly been debunked and hasn’t proven to be an issue.

Not sure about the noise, but they’re using the same common rail diesel technolgy being used in automotive and those engines are hardly detectable as being diesel to the common ear.

As for fuel economy, if you run a commercial tourism or charter business and rack up 1,500 - 2,000 hrs/yr while commonly running under load, is it better to run a petrol outboard vs diesel? The 300 Hp diesel are estimating up to 40% better fuel economy at WOT, but will drop down and say the diesel is running at 3,000 rpm where the petrol would need to run at 5,000 to meet the same speed due to the lower torque. 73 LPH vs 53 LPH is a difference of 30k - 40k liters of fuel annually at these running hours. In that commercial case the diesel would pay for itself in under 1 year. Yamaha Outboard Fuel Consumption | Liters per hour LPH https://www.boat-fuel-economy.com/yamaha-outboard-fuel-consumption-liters

I’ve worked with 2 different commercial businesses in Maldives and South Africa, and both rebuild their Yamaha 250’s and 300’s annually at 1,500 hours. They sell them after the 2nd year because the ongoing service costs become excessive beyond Y2.

 

Sounds like a mix of operator abuse and very poor maintenance. You are dismissing someone who owns 60 of these engines. I am pretty sure he has some knowledge of them.

 

Sounds like you are trying to get me to argue which I’m not looking to. I didn’t mention anything about someone who owns 60 engines. I simply commented to the weight, the substantial fuel savings vs the petrol outboards, and 2 commercial businesses I’ve dealt with.

If you don’t mind me asking, what is your background? It’s nothing personal I’m just curious.

 

You have trolled every post I have submitted on this thread so I don't think it's me chasing an argument. You refuse to accept any opinion but yours. Yes I was a mechanic for many years. I post under my real name.

 

Sorry you feel offended as that wasn’t my intention. I’ve not been ‘trolling’ any posts, just sharing a different view I had on the topic(s) based on my professional experience. I have interest in the diesel outboards based on the different commercial businesses I’m involved with that use only petrol products. Also, not just my opinions, rather the CFR and EPA guidelines the manufacturers are required to design against.

 

Apology accepted. I apologise for my remarks too. Forums are very impersonal and small disputes can get out of hand. .

 

No worries and thanks, I fully agree.

 

Its a specialist product for a limited market, the mass market will still be with petrol engines. I would also say most recreational users would be put off by fumes, especially at low speeds, like trolling.

 

You may be right, I suspect they are aimed at a focused market, however so was the diesel in pickups but now you see them moving aggressively into the 1/2 models which are used less for long haul towing. Have you been onboard a boat with one of these Tier 3 approved outboard models that exhaust below the waterline? Personally, I’ve not so I can’t say on the fumes.

 

it would be like the old 2S, one imagines, trolling downwind could be sickening at times, although oil injection reduced the issue a good deal. At speed, it is not an issue.

 

What are these claims based on?

 

Experience ! Many a "hurl" over the side is stimulated, or abetted, by fumes when trolling. The oil injected 2S burnt a lot less oil at low speeds, than the earlier non-injected motors.

 

modern common rail diesels are almost smokeless, they can't be compared to a 2 stroke outboard.

 

i wonder how they control emissions seems most cars and trucks have those horrible dpf filters.

 

You think it is as inoffensive a smell as that of unleaded petrol fumes ?