diesel engine advice

[adhdan]

Hi, new to forum so you can answer my dumbass questions

Looking at a couple used boats, quite fancy a diesel inboard over a petrol outboard to save on fuel

One boat that takes my fancy has a mercury 2.8l qsd 220hp with bravo 3 outdrive,

The other boat has a volvo d4 225hp penta

The boat with the mercury is to use a term very loosely 'cheap' im wondering if its because of the engine

Anyone have experience with the above engines, maintenance, parts availability, what i should look out for
Thanks
Dan

 

[adhdan]

forgot to add, the mercury is 2017 the volvo 2006

 

[simonfraser]

how many hours are you likely to use the boat for ?
petrol is not available as readily as diesel
unless you do monster hours the price difference in diesel vs petrol usage is negated by maintenance

keeping boat in the water or out ?

outboards have better access for maintenance

let us know some boats you are intersted in and we'll make some 'helpful' suggestions

 

[adhdan]

how many hours are you likely to use the boat for ?
petrol is not available as readily as diesel
unless you do monster hours the price difference in diesel vs petrol usage is negated by maintenance

keeping boat in the water or out ?

outboards have better access for maintenance

let us know some boats you are intersted in and we'll make some 'helpful' suggestions

im in an industry that has a large tank of discount diesel bought in bulk so for me its much cheaper

keeping the boat trailered in a shed. Was looking at biggest i can legally tow so 3.5ton inc trailer, 8ish metres long, 3 wide. Me the wife & 3 kids would need to be able to sleep on it at a push although 1 child is much older and probably not likely to want to come with us.

Parker 800 weekend & the finnmaster 7600

i personally really like the look&style of the pilot cabin weekender boats, i also quite like the quicksilver weekender with the side sliding door next to the helm, looks handy for nipping out to tie a rope in locks.

Will be using for canals/rivers & coastal.

 

[Ferris]

Cummins QSD 2.8 220 HP on Stern Drives

 

[ChromeDome]

The link shared by Ferris tells a lot.

If you search for sterndrive issues make sure you sit down before diving into the results.

Trailer boats commonly have outboards and for a lot of good reasons.

 

[adhdan]

The link shared by Ferris tells a lot.

If you search for sterndrive issues make sure you sit down before diving into the results.

Trailer boats commonly have outboards and for a lot of good reasons.

I read through the link but other then questions and the odd speculation i didnt take much away from it. If those engines have problems no one has said what the problems are....but i get the theme, 2.8 qsd bad.
As for sterndrives, i'll do some googling but your welcome to give me the crash course , what makes stern drives so bad on trailered boats? I would of thought being out the water would be a bonus to them & easier to do maintenance and check them over?

 

[simonfraser]

stern drive on trailer, you're still stuck with poor access to the internal engine

outboard has a finer pitch and maneuvers much better than stern drive

 

[scottie]

Where do you intend to use boat if not sea going speed limits often apply therefor less HP requirement ETC

the Volvo Set up is usually recommended but at this vintage case by case applies
being trailed does have advantages but if used in the same location you might get over the experience rather quickly
fuel is a major factor cost wise but repairs can run away very quickly and having a boat parked up is very unpleasant

 

[adhdan]

Where do you intend to use boat if not sea going speed limits often apply therefor less HP requirement ETC

the Volvo Set up is usually recommended but at this vintage case by case applies
being trailed does have advantages but if used in the same location you might get over the experience rather quickly
fuel is a major factor cost wise but repairs can run away very quickly and having a boat parked up is very unpleasant

ive got a small river cruiser, enjoy it but its not big enough, i want something big enough to sleep 2/3 adults & 2 kids. inland for weekends & holidays with the family and be able to go off shore and get some experience/confidence

I have just watched a few videos about stern drives and i see your points. the biggest one for me is the rubber gasket that stops your boat sinking, i had thought the drive shaft came out just above the waterline and the leg pivoted down similar to an outboard but i see its all beneath the waterline and can swing up.

Just erks me somewhat to pay £1.60 a L for petrol when i got £0.85l diesel at home

 

[simonfraser]

'rubber gasket that stops your boat sinking'

may not sink, just rust your bits

 

[ChromeDome]

In short:

Before making financial decisions do get a few quotes for the annual servicing of a sterndrive & engine.

Not inexpensive, which tempts owners to skip or do it partially. Without meticulous care, they become time bombs and when they decide to 'surprise' you, it most often ends up in tears.

You put a cast iron engine into a confined compartment, then cool it with sea water - if not fitted with fresh water cooling (which many trailer boats are not - and you still need the sea water to get in - then to pass a heat exchanger). Sea/salt water will make cast iron corrode, fast..
Next, you fit a plate on the transom to carry the sterndrive, and allow it to turn from side to side and tilt up.
The shaft connecting the engine to the drive is supported by bearings, runs through a universal joint and into the gearbox integrated in the drive upper housing. To protect it from corroding it all runs inside a rubber grommet (and when humidity gets in, it'll corrode before you know).
At the same time, seawater needs to be picked up by the drive and fed through the drive, hoses, grommets to the engine's cooling jacket.
After doing its job the sea water is sent out via the sterndrive, after being mixed with exhaust. Again via mixing devices, inside grommets and the sterndrive.
Since the gearbox lives in the sterndrive you also need to route a shifting cable out via the transom plate.

More seals that can fail - and then we didn't mention the prop shaft.

An outboard is made of an alloy that is resistant to corrosion and sits on top of the transom. No need for a contraption to allow it to turn or tilt in the middle or pass anything through the transom. And not put into a confined compartment.

Ever thought of repowering? An outboard is bolted onto the transom. By unbolting it and disconnecting the cables, it can be lifted off. Fitting is the same in reverse and you can select any make or model to fit.

Taking the engine, transom plate and sterndrive off a boat is a different project. And given the cutout for the drive, your choice for replacement is limited.

 

[adhdan]

well... thanks for the input, i think youve pretty much turned me off the idea of owning a diesel power. I'll change the search filter to 'petrol' and try again . Interestingly there is another weekender boat the same as the one with the merc qsd engine that is fitted with a 250hp evinrude etec outboard, same price but 4 years older.

 

[jointventureII]

I read through the link but other then questions and the odd speculation i didnt take much away from it. If those engines have problems no one has said what the problems are....but i get the theme, 2.8 qsd bad.
As for sterndrives, i'll do some googling but your welcome to give me the crash course , what makes stern drives so bad on trailered boats? I would of thought being out the water would be a bonus to them & easier to do maintenance and check them over?

As the owner of a diesel sterndrive (a mercruiser 4.2 320hp on a Bravo 2) I'd say, check if the Bravo 3 outdrive is the X version. The Bravo 3 won't be able to handle much torque (this is the major sticking point of diesel engines in sterndrives) and you'll see / hear / read about plenty of cases of the drive not being able to sustain the torque.

The huge plus with diesel is that at 6-7 knots, it consumes 3.5 litres / hour, on a 3 ton 25ft boat.

Even at 21 knots, which is a fast cruise, it burns 30 litres / hour. The petrol equivalent would be at least 30% more, I'd imagine.

 

[Ferris]

well... thanks for the input, i think youve pretty much turned me off the idea of owning a diesel power. I'll change the search filter to 'petrol' and try again . Interestingly there is another weekender boat the same as the one with the merc qsd engine that is fitted with a 250hp evinrude etec outboard, same price but 4 years older.

Jesus, don’t search evinrude or etec !

Short version - Evinrude went bust due to etec.

 

[adhdan]

As the owner of a diesel sterndrive (a mercruiser 4.2 320hp on a Bravo 2) I'd say, check if the Bravo 3 outdrive is the X version. The Bravo 3 won't be able to handle much torque (this is the major sticking point of diesel engines in sterndrives) and you'll see / hear / read about plenty of cases of the drive not being able to sustain the torque.

The huge plus with diesel is that at 6-7 knots, it consumes 3.5 litres / hour, on a 3 ton 25ft boat.

Even at 21 knots, which is a fast cruise, it burns 30 litres / hour. The petrol equivalent would be at least 30% more, I'd imagine.

Would the bravo3 still be a concern with a 220hp? I think that’s towards the lower end of the power it’s rated for

 

[adhdan]

Jesus, don’t search evinrude or etec !

Short version - Evinrude went bust due to etec.

I searched .
Sounds like they are incredibly good engines ….until there not

 

[jointventureII]

Would the bravo3 still be a concern with a 220hp? I think that’s towards the lower end of the power it’s rated for

Someone more knowledgable than me will be able to confirm but I think a diesel 220hp would be on the limit. For petrol engines it's well within the limit. Certainly if / when I ever upgrade mine, it'll be for a 3X or 3XR. Unfortunately that'd require selling a few body parts!

 

[ChromeDome]

I'll change the search filter to 'petrol' and try again.

If you just filter to "outboard" and focus on 4-strokes you'll the relevant results.

 

[volvopaul]

Hi, new to forum so you can answer my dumbass questions

Looking at a couple used boats, quite fancy a diesel inboard over a petrol outboard to save on fuel

One boat that takes my fancy has a mercury 2.8l qsd 220hp with bravo 3 outdrive,

The other boat has a volvo d4 225hp penta

The boat with the mercury is to use a term very loosely 'cheap' im wondering if its because of the engine

Anyone have experience with the above engines, maintenance, parts availability, what i should look out for
Thanks
Dan

If you want good service and part buy the Volvo , the merc is a simpler engine , in actual fact the base automotive unit adapted by Mercury to marine use , you won’t find a dealer on every corner or the knowledge you find with Volvo . It would be cheaper if it failed to rebuild than a Volvo D4 as you need a short or long block when they fail , the Volvo was designed by Deutz under license and is solely used by Volvopenta, the unit cannot be re bored as no oversize pistons are available genuine parts , you do see aftermarket parts available but I wouldn’t trust them based on experience over the years . The choice is yours.