Mercruiser Diesels

[Richie]

Hi,

Any views on Mercruiser Diesels (particulalry 4.2L - 95 vintage, 220hp) - reliable, economical, money pit etc?

One boatyard advised me to steer clear of Mercruiser Diesels calling them 'black scrap' but would be good to get a more balanced view. Certainly they don't seem as common - would I be likely to encounter any issues with servicing / parts availability (say in the Poole area)?

Thanks for any advice.

Rich

 

[volvopaul]

I have heard them called worse than black scrap! however if I was buying and had the choice dependant on price of the boat I would steer clear, they dont have the parts back up as volvo, yes some parts are getting scarce, you dont have a dealer at nearly every port, the drives are a nightmare, the engines are underpowered in some applications, the engine base unit is Italian anyway, they have 6 cylinder heads instead of 1, so stripdowns are more complex, you get oil leaks, they do overheat when the coolers are just slightly blocked, I could go on, I would put a search on the forum about mercruiser to give you an idea, thers plenty on here.

I a word, buy a volvo!

 

[PCUK]

Could you be ever so slightly biased!!!!
Volvo aren't exactly clean as the driven snow.
In another word, Buy Yanmar!

 

[DAKA]

Hi,

Any views on Mercruiser Diesels (particulalry 4.2L - 95 vintage, 220hp) - reliable, economical, money pit etc?

Parts are very easily obtainable.
Parts can be ordered from
Cummins
Cumins-mercruiser
or mercruiser dealers

A few years ago in Poole (Cobbs) I wanted an air filter, there were three dealers there alone.

CMD went out there way to appoint an agent in every port, there are no problems.

The air filter wasnt in stock as it happened, because it is washable, thats right, put it in a bucket of warm soapy water and put it back on, bit of saving compared to £20 each from VP.
I ordered a spare filter that arrived before the bridge lift the following morning, cost £5-£6

You will instantly notice how smooth the power is and that it is clean, no sooty stern/tender.
start up is virtually smoke free.

For 1995 the engine was way ahead of VP.

The block as already mentioned is VM, which is part of the GM/Detroit motor group with recent ties to Gaz.
The same engine is used in all sorts of Industrial uses including road sweepers apparently, more commonly seen in Land rovers.
I believe Nanni (marine diesel specialists) are also about to launch a new range based on the same 4.2L engine.

I have been very pleased with my Twin 4.2L D300 hp (2004).

In 5 seasons they have only let me down once (full report to follow as soon as I get chance).

In my opinion the 220 hp 4.2L 1992 were 10 years ahead of VP at that time and the new 350 hp 4.2L have the benefit of 10 years production over the new VP D4 and D6 which are now undergoing teething issues.

Without doubt you will find prejudice against anything other than VP which is wrong but may well effect your residual value.

 

[andrewbarker]

Actually, there were reliability and overheating issues (hotspots) with both LR and Jeep road applications.

 

[DAKA]

The LR with a 4.2 engine that had a reputation for overheating was the V8 petrol (not a VM engine).

Dont know anything about Jeeps, they weren't available in Europe back then were they ?

 

[spannerman]

Sorry but I'm going to have to disagree with Volvopaul on this one.
As a Volvo mechanic for 29 yrs and always owned Mercruisers myself I'd go for the Mercruiser diesel over a Volvo of similar vintage.
First the mechanical issues, I've never done a head gasket yet, (I'd say having separate cylinder heads is an advantage as you don't have bust your back lifting a big cast iron lump as on Volvo) and I have done more than my share on Volvos.
Never had any real overheating problems, but cleaned dozens of coolers on Volvos.
Have rebuilt over a hundred VP drives with water in but only half a dozen Mercruiser drives.
And as others stated its a much cleaner exhaust, starts easily and runs very smoothly.
Also its a bigger displacement block than Volvo (3.6l)so is less stressed.
This is just my humble opinion gleaned from hands on experience BTW.

 

[Richie]

Thanks for the feedback folks, opinion seems a bit split - maybe I also need to give more thought to resale value even if the engines are sound.

Yes engines were incredibly smooth on start up, but then I've been used to the rather more agricultural thrum of 30 yr old Ford Mermaids the past few years. In fact reminded me more of a straight 6 petrol than a diesel I was that impressed.

Either way I suspect I'd need a marine engineer with some knowledge of these engines to check them over for me. I expect with VP there'd be no shortage of expertise, be good to know if there are any recommendations for somebody with Merc Diesel expertise in the Southampton area?

 

[nicho]

When we had a new S37 built in 1997, we specified Mercruisers D4.2L, 'cos at the time the alternative KAD 43's were getting bad press for lack of reliability. We had the single prop Bravo 2 outdrives, and they too gave good service. In our experience, the Mercs were very (very!) smooth, quiet, economical and produced little smoke on start up.

In the 200 hours we did with them, they were also reliable - can't talk about spares availability 'cos they never needed any. The boat was eventually sold and went to the Med for a few years, but I happen to know it's back in the UK now, and as far as I know, the good old Mercs are still giving sterling service.

 

[Bandit]

I had a Halmatic 34 with a pair of Mercruiser 3.6l 180hp 6 cylinder engines on shafts that i bought in 1993.

The boat was a semidisplacement.

The engines were about two or three years old when i bought the boat so about 1990.

I had so many problems with the engines following overheating that I replaced them in 1998 as they were uneconomical to repair.

The engines were VM base units with BMW badges and Mercruiser badges on as mecruiser took over BMW marine.

Spares were a problem, and i sold the gearboxes and scrapped the the engines.

I think the 220 is the same base engine.

My advice is dont touch them with a barge pole.

 

[volvopaul]

Sorry but I'm going to have to disagree with Volvopaul on this one.
As a Volvo mechanic for 29 yrs and always owned Mercruisers myself I'd go for the Mercruiser diesel over a Volvo of similar vintage.
First the mechanical issues, I've never done a head gasket yet, (I'd say having separate cylinder heads is an advantage as you don't have bust your back lifting a big cast iron lump as on Volvo) and I have done more than my share on Volvos.
Never had any real overheating problems, but cleaned dozens of coolers on Volvos.
Have rebuilt over a hundred VP drives with water in but only half a dozen Mercruiser drives.
And as others stated its a much cleaner exhaust, starts easily and runs very smoothly.
Also its a bigger displacement block than Volvo (3.6l)so is less stressed.
This is just my humble opinion gleaned from hands on experience BTW.

I do agree with you, but when you look how many volvos there are about compared to the mercs, and im only talking about the uk, there are bound to be more volvo faults than mercs put to press.

I just think the mercs are not as good, when you have removed and stripped some of the 4.2 220s out of broom boats and the way they have blown up its never inspired me to buy one, though the early kads were just as bad! and brooms never fitted them or offered the kad42 in there boats, the yanmars is quite rightly a better option than the volvo in some cases.

 

[davedpc]

Hi,

Any views on Mercruiser Diesels (particulalry 4.2L - 95 vintage, 220hp) - reliable, economical, money pit etc?

One boatyard advised me to steer clear of Mercruiser Diesels calling them 'black scrap' but would be good to get a more balanced view. Certainly they don't seem as common - would I be likely to encounter any issues with servicing / parts availability (say in the Poole area)?

Thanks for any advice.

Rich

Have run 4.2D's for six years without any major problems. Most spares no problem and there is also VM to get major engine spares direct at much less cost than m/c. As spannerman says if you are unfortunate to have a head go its only one not 6. The c/heads are ally and much lighter and one gasket services 2 heads. Also after spending much time on volvosplutters ive never had overheating due to the primary water filter blocking up and subsequently the water pump impellor disintergrating as on the volvo block it is located after the filter. I also think m/c outdrives are much more bullet proof than the green ones.

 

[oldgit]

Which way to go ?

What ever you decide to go for,as others have said,make sure there is a proper agent in your area so that can get you ALL bits,preferably from stock and locally.
Parts for my engines which are thirty years old are still available off the shelf and even odd ball hens teeth stuff can be summoned from engine heaven within 48 hours.Stuff for my engines is available anywhere.
Most service parts can also be obtained cheaply from motor factors and a vast industry of pattern parts providers has appeared along with bods to to service the beasts.
The largest stockist of secondhand engines/outdrives and spares in UK is a couple of hours drive from you.
Its got to be Volvo Penta then innit.

 

[DAKA]

I do agree with you, but when you look how many volvos there are about compared to the mercs, and im only talking about the uk, there are bound to be more volvo faults than mercs put to press.

Just a bit of trivia

Volvo penta produce about 10 000 diesel engines a year for world wide use.
VM produce 100 000 diesel engines a year for world wide use, they have specialised in diesel engines in Cento which is world famous as the home of Ferrari, Maserati and Ducati .

 

[RichLangtry]

Mercruiser / BMW diesels

Gentlemen,

This engine was first introduced to the marine market by BMW in the early 1980's as a 3.6 liters 6 cylinder. When you're reputedly the best engine manufacturer in the world, for BMW to outsource engines could be considered a huge compliment to VM Motori.

At the end of 1987, Mercury acquired the BMW plant in Belgium and continued manufacturing the 'BMW' D636 and D530 engines.

In the early 1990's, the 3.6 was bored and stroked to 4.2 liters. These continue to be 'IDI' engines. With the D254 assembly in Belgium ended. VM now produced and badged the engines as Mercruisers. In the lates 90s, VM modified the engine to direct injection (DI).

Around 2004, Mercury and Cummins partnered in CMD with a majority of engine and parts distribution falling on the Cummins' distribution system.

This is why there is confusion in the marketplace.

Our perception is the Cummins sales staff would rather sell their American made engines over a foreign one made in Italy.

As to quality, this engine is a tunnel bore design, that is the crankshaft is housed inside the block (like a camshaft) rather than strapped on to the bottom. Structurally significiantly better.

The earliest BMW models cooling system was marginal. Overheating caused havoc with the top end. A major Italian rebuilder of these engines automatically replaces the cylinder heads with new ones.

Now as to parts availability. The Mercruiser early parts catalogues were mere copies of the better quality BMW parts catalogues. Mercury changed the BMW part numbers to their own system. We find Mercury's part number system for these engines to be very confusing and we are sure that the Cummins / CMD parts staff found the same problems/issues.

But the parts are out there. The problem is ordering and getting the correct part. Patience is defintely required. Parts are more readily available in Europe than other parts of the world.

Service.

Mercruiser did offer training schools on these engines. Finding a mechanic confident in working on these engines is a challenge. In North Birwick, Maine, Phil Thain at PT Engines LLC. is a good bet. In Scotland, Kilmarnock Engines Services. In New Zealand, Performance Imports. In Australia, Empire Bay Marina. In Italy, Ghisellini. In Finland, Telva. These are but a few that come to mind.

We cannot comment on the installations using the Mercruiser Bravo drives.

These are inline 6 cylinder engines, and therefore smoother running than the alternatives, and easier to work on as well.

Rich Langtry
V12 Engineering
www.bmwmarine.com

 

[rafiki_]

Thanks for the feedback folks, opinion seems a bit split - maybe I also need to give more thought to resale value even if the engines are sound.

Yes engines were incredibly smooth on start up, but then I've been used to the rather more agricultural thrum of 30 yr old Ford Mermaids the past few years. In fact reminded me more of a straight 6 petrol than a diesel I was that impressed.

Either way I suspect I'd need a marine engineer with some knowledge of these engines to check them over for me. I expect with VP there'd be no shortage of expertise, be good to know if there are any recommendations for somebody with Merc Diesel expertise in the Southampton area?

Tom, AKA Mercuryman off this forum is the local Southampton expert. He has given me some great advice on my 1.7 Mercs (Isuzu units). The CMD partnership has been dissolved, but I have no idea if this has caused a problem with spares, as I tend to get my engine parts from the local Vauxhall dealer and drive bits mainly from USA where they are much cheaper.

The Land Rover VM's were 4 cyl 2.4 engines. Yes, there were some cyl head and reliability probs, mainly when full chat down long hills where they were not fuelling enough, hence starving the cylinders of lubrication and cooling fuel. Would ot replicate in a boat, as the downhill bits don't last very long!

 

[carlton]

This thread is almost three years old!

...Gentlemen...

...as the downhill bits don't last very long!

 

[Sheppy]

Hi,

Any views on Mercruiser Diesels (particulalry 4.2L - 95 vintage, 220hp) - reliable, economical, money pit etc?

One boatyard advised me to steer clear of Mercruiser Diesels calling them 'black scrap' but would be good to get a more balanced view. Certainly they don't seem as common - would I be likely to encounter any issues with servicing / parts availability (say in the Poole area)?

Thanks for any advice.

Rich

Hi Rich,
I researched Mercruiser diesels as extensively as I could prior to buying my boat with a 1998 2.8l D-Tronic 165. I found mixed reviews across the range but nothing to put me off them. The early ones are little heavy and under powered but then I understand VP's were too. I think they got common rail technology in about 2000 so you're basically looking at electronically injected single fuel pump which I guess is a midway technology. I've not had my boat for too long and have had a couple of annoying issues such as a blown temp sensor and a failed potentiometer (the latter being quite pricey). She is smoother than I expected and mines just a four pot but she’s a little noisy so I'm in the process of soundproofing the engine bay.
But so far she seems to run on air and I’m fairly happy but have considered re-powering mainly to gain more power than anything else.
If they're running well and have a good service record I wouldn't worry too much. You may find that any problems come to light after a few runs on full power, so it might be worth working out any gremlins after the purchase and maybe just put a little money aside for any surprises. And I’ve no evidence to suggest spares are unavailable but I guess it’s inevitable at some point.
Good luck.....

 

[Elessar]

I have heard them called worse than black scrap! however if I was buying and had the choice dependant on price of the boat I would steer clear, they dont have the parts back up as volvo, yes some parts are getting scarce, you dont have a dealer at nearly every port, the drives are a nightmare, the engines are underpowered in some applications, the engine base unit is Italian anyway, they have 6 cylinder heads instead of 1, so stripdowns are more complex, you get oil leaks, they do overheat when the coolers are just slightly blocked, I could go on, I would put a search on the forum about mercruiser to give you an idea, thers plenty on here.

I a word, buy a volvo!

You keep spreading the same bollox Paul, but it remains bollox.

You are however not alone. So the price of merc boats remains lower. So buy right bearing in mind resale value.

Parts prices are better if you buy from the states. You can't buy Volvo (or Yanmar) parts from the states as they operate restrictive practices that would be illegal in the EU.

I've just bought my 4th big boat, the first with volvos. The parts prices are eye watering.

Buy mercs with your eyes open. Get an engineer who understands them like mercuryman of this forum. Buy at the right price and expect to hear "black junk" noise when you sell.

I really don't understand why when volvo market stuff that is unfit for purpose, like steering rams that dont steer for long, and prop that don't propel for long, yet it's never volvo's fault in the eyes of some.

 

[rafiki_]

You keep spreading the same bollox Paul, but it remains bollox.

You are however not alone. So the price of merc boats remains lower. So buy right bearing in mind resale value.

Parts prices are better if you buy from the states. You can't buy Volvo (or Yanmar) parts from the states as they operate restrictive practices that would be illegal in the EU.

I've just bought my 4th big boat, the first with volvos. The parts prices are eye watering.

Buy mercs with your eyes open. Get an engineer who understands them like mercuryman of this forum. Buy at the right price and expect to hear "black junk" noise when you sell.

I really don't understand why when volvo market stuff that is unfit for purpose, like steering rams that dont steer for long, and prop that don't propel for long, yet it's never volvo's fault in the eyes of some.

+1