New engine or start tinkering?

[Andrew E]

I've got an early 1970s Volvo MD7A which starts first time and runs pretty well apart from alot of white exhaust smoke. She hasn’t missed a beat in the 30 hours put on her this season. Other than that, I have no idea of her history apart from the fact she was rebuilt sometime in the 10-12 years. I do all the servicing myself.

Anyway what do you think I should do? Start tinkering to diagnose the white smoke? Pay an engineer to survey the engine - I don’t particularly trust any of these marine engineers due to being ripped off/misadvised in the past. Or start rebuilding the engine myself.
Or finally, get a few quotes for a new / refurbished engine?

One can only service an 40 year old engine for so long and I would hate to have a season wrecking incident, so I’m convincing myself the new engine option is best. Especially as my current engine is working and probably worth a few quid to someone.

Out of interest, roughy how much are we talking about for a new engine (Bukh DV20) to replace the MD7A, including fitting and any changes to the propshaft. A new Beta would be my preferred choice, but they’re extremely expensive, perhaps 60% to 70% the value of my boat, so probably a no no unless I win the lottery.

Cheers

 

[vyv_cox]

White smoke is usually an indication that there is a fuel problem, perhaps injectors that have carbon deposits that mis-direct the spray pattern. I would have them serviced first, easy enough to get them out and no need to involve 'marine' engineers. If the smoke is only produced in the first couple of minutes it is nothing to be concerned about. My BMC smokes like crazy when it first starts but settles down when warmed up.

Make certain that your white smoke is not steam, which can confuse the issue. Some engines are renowned for this but I don't know if yours is one.

 

[prv]

Would help to say where you are - someone might be able to recommend a trustworthy local mechanic to have a look.

I don't think any new engine will be much cheaper than the Beta, so if that's a no-no then so is any new engine. I'm also not convinced it's really necessary if the current one is still working well apart from the smoke.

I'm not a diesel expert, but could white smoke be due to the injectors? Probably wouldn't be too much to take those to a specialist (think farm and site machinery rather than marine) for a checkup. I could be talking nonsense on this though, sure someone more knowledgeable on engines will be along shortly

Even if something does go wrong, an engine problem doesn't have to be a season-wrecking incident. People used to sail around all the time with chronically unreliable engines. Balky Stuart Turners etc are well before my time, but even so I've had quite a few unexpected engine failures over the years and touch wood no disasters yet. Remember simple things like favouring the windward side of a channel when it's breezy and there's no urgent need to be six feet off the bricks to leeward. Have at least one sail ready to go in a hurry to regain control (in my case the boat is best under jib alone in close quarters anyway, so I ignore the RYA dogma about mainsail covers). If you have complicated anchor lashings, maybe cast them off before entering confined waters just in case (standard procedure for commercial shipping!). Don't roar about with way more speed than you need in marinas, just in case you can't get reverse thrust to brake (I once had the engine lever of a chartered boat come off in my hand at that crucial moment!). If you can turn it from a potential disaster into a potential inconvenience, you might be more relaxed about running an older engine?

Pete

 

[Kukri]

Would help to say where you are - someone might be able to recommend a trustworthy local mechanic to have a look.

I don't think any new engine will be much cheaper than the Beta, so if that's a no-no then so is any new engine. I'm also not convinced it's really necessary if the current one is still working well apart from the smoke.

I'm not a diesel expert, but could white smoke be due to the injectors? Probably wouldn't be too much to take those to a specialist (think farm and site machinery rather than marine) for a checkup. I could be talking nonsense on this though, sure someone more knowledgeable on engines will be along shortly

Even if something does go wrong, an engine problem doesn't have to be a season-wrecking incident. People used to sail around all the time with chronically unreliable engines. Balky Stuart Turners etc are well before my time, but even so I've had quite a few unexpected engine failures over the years and touch wood no disasters yet. Remember simple things like favouring the windward side of a channel when it's breezy and there's no urgent need to be six feet off the bricks to leeward. Have at least one sail ready to go in a hurry to regain control (in my case the boat is best under jib alone in close quarters anyway, so I ignore the RYA dogma about mainsail covers). If you have complicated anchor lashings, maybe cast them off before entering confined waters just in case (standard procedure for commercial shipping!). Don't roar about with way more speed than you need in marinas, just in case you can't get reverse thrust to brake (I once had the engine lever of a chartered boat come off in my hand at that crucial moment!). If you can turn it from a potential disaster into a potential inconvenience, you might be more relaxed about running an older engine?

Pete

Good advice.

I got along for years with a gaff cutter and a 1967 MD2 that would run for 20 minutes before it overheated. The 20 minutes was all I ever needed - enough to get into or out of a marina or out of a tight spot.

 

[pvb]

A new engine is a serious expense, and I can't imagine that a Bukh DV20 is going to be significantly cheaper than a small Beta. The cost of the engine itself is by no means the end of the story, by the time it's been fitted, maybe with a new propshaft, prop, seal, ancillary items, you could be looking at a few thousand pounds more. Unless you plan to keep your boat for a very long time, it's not an economic proposition, as you won't get the cost back when you sell, although it will make it easier to sell.

White smoke could be unburnt fuel, or it could be steam. Does it produce white smoke immediately on start-up with a cold engine? If so, it could be poor combustion and there are some simple things you can try yourself. Check the valve clearances. Check that the engine is reaching its correct temperature, if not, replace the thermostat. Possibly add a cetane improver to the fuel.

Reconditioned engines are available, but you need to be extremely careful (see current thread about MD2020 reconditioned engine). And, of course, the extra costs involved in installing a new engine can be similarly high with a reconditioned engine.

If you're close to convincing yourself to buy a new engine, get some installed quotes first, and then you might want to re-consider.

One final point. On my last boat, the Volvo 2003T chucked out smoke for years. I had the injectors serviced, had the compression checked, but it still smoked. But it kept running well.

 

[Andrew E]

White smoke is usually an indication that there is a fuel problem, perhaps injectors that have carbon deposits that mis-direct the spray pattern. I would have them serviced first, easy enough to get them out and no need to involve 'marine' engineers. If the smoke is only produced in the first couple of minutes it is nothing to be concerned about. My BMC smokes like crazy when it first starts but settles down when warmed up.

Make certain that your white smoke is not steam, which can confuse the issue. Some engines are renowned for this but I don't know if yours is one.

The smoke is pretty consistent, obviously smokes like crazy at the start and then settles down to a more steady smoking. I'll have a nosey at the fuel injectors. Thanks.

To be honest I'm pretty certain it's smoke due to the smell. I was going to have a nosey at the thermostat aswell incase there's a bit of steam in there aswell.

 

[vyv_cox]

The smoke is pretty consistent, obviously smokes like crazy at the start and then settles down to a more steady smoking. I'll have a nosey at the fuel injectors. Thanks.

To be honest I'm pretty certain it's smoke due to the smell. I was going to have a nosey at the thermostat aswell incase there's a bit of steam in there aswell.

I am fairly certain that the reason Bukh engines steam is due to the design of the exhaust manifold. I doubt very much that you would find steam in the thermostat housing.

 

[Andrew E]

Would help to say where you are - someone might be able to recommend a trustworthy local mechanic to have a look.

I'm in the Southampton area and have been let down by a three separate marine engineers so lack alot of faith.

Even if something does go wrong, an engine problem doesn't have to be a season-wrecking incident. People used to sail around all the time with chronically unreliable engines. Balky Stuart Turners etc are well before my time, but even so I've had quite a few unexpected engine failures over the years and touch wood no disasters yet. Remember simple things like favouring the windward side of a channel when it's breezy and there's no urgent need to be six feet off the bricks to leeward. Have at least one sail ready to go in a hurry to regain control (in my case the boat is best under jib alone in close quarters anyway, so I ignore the RYA dogma about mainsail covers). If you have complicated anchor lashings, maybe cast them off before entering confined waters just in case (standard procedure for commercial shipping!). Don't roar about with way more speed than you need in marinas, just in case you can't get reverse thrust to brake (I once had the engine lever of a chartered boat come off in my hand at that crucial moment!). If you can turn it from a potential disaster into a potential inconvenience, you might be more relaxed about running an older engine?

Pete

I always motor with the main up and have the jib ready to go. It's on those days were there's little wind that worry me the most.

A new engine is a serious expense, and I can't imagine that a Bukh DV20 is going to be significantly cheaper than a small Beta. The cost of the engine itself is by no means the end of the story, by the time it's been fitted, maybe with a new propshaft, prop, seal, ancillary items, you could be looking at a few thousand pounds more. Unless you plan to keep your boat for a very long time, it's not an economic proposition, as you won't get the cost back when you sell, although it will make it easier to sell.

I saw advertised a reconditioned Bukh DV20 with less than 250 hours for 1.5k but I'm extremely wary of swapping the devil you know for the devil you don't.

Does it produce white smoke immediately on start-up with a cold engine? If so, it could be poor combustion and there are some simple things you can try yourself. Check the valve clearances. Check that the engine is reaching its correct temperature, if not, replace the thermostat. Possibly add a cetane improver to the fuel.

Immediately on start-up every time, cold or not cold.

 

[pvb]

I saw advertised a reconditioned Bukh DV20 with less than 250 hours for 1.5k but I'm extremely wary of swapping the devil you know for the devil you don't.

You didn't say "reconditioned Bukh DV20" originally. I too would be hugely cautious about any reconditioned engine, perhaps unless it came from an engine maker's dealership.

 

[prv]

I'm in the Southampton area and have been let down by a three separate marine engineers so lack alot of faith.

Ok. I haven't needed a mechanic so have no first-hand recommendations, but I know lots of people sing the praises of VolvoPaul on these forums. He seems to be mostly a motorboat guy, but I think he's mentioned work on yachts as well and either way it can't hurt to ask.

I've also heard nothing but good about Tom Parker, aka Tompa Marine based at Kemp's Quay on the Itchen (but mobile in a van). He did some good work on my mate's ancient knackered petrol speedboat that everyone else turned their nose up at.

I always motor with the main up and have the jib ready to go. It's on those days were there's little wind that worry me the most.

On the bright side, when there's little wind you're unlikely to blow into anything at any great speed

Pete

 

[Andrew E]

Ok. I haven't needed a mechanic so have no first-hand recommendations, but I know lots of people sing the praises of VolvoPaul on these forums. He seems to be mostly a motorboat guy, but I think he's mentioned work on yachts as well and either way it can't hurt to ask.

I've also heard nothing but good about Tom Parker, aka Tompa Marine based at Kemp's Quay on the Itchen (but mobile in a van). He did some good work on my mate's ancient knackered petrol speedboat that everyone else turned their nose up at.



On the bright side, when there's little wind you're unlikely to blow into anything at any great speed

Pete

Thanks for the recommendations. Will look into that.

More worried about one of those great big cargo ships steaming into me

Broke down once before in another yacht in Southampton Water with an inbound cargo ship just over a mile away. Luckily there was wind and we unfurled the jib and sailed clear of the channel. I've always wondered how quickly the harbour master could tug you out of the way - pretty quickly I assume.

 

[prv]

Broke down once before in another yacht in Southampton Water with an inbound cargo ship just over a mile away. Luckily there was wind and we unfurled the jib and sailed clear of the channel. I've always wondered how quickly the harbour master could tug you out of the way - pretty quickly I assume.

If they were nearby I'm sure they could get a line on you pretty quick, but they aren't always out patrolling and when they are they could be a long way away. Better to motor up the secondary channel (or outside the buoys altogether), then the issue can't arise

Pete

 

[Jcorstorphine]

Is the Bukh 20 @ 20 hp not a bit too big Your MD7a is ony 13 hp. Like others have said be weary of 2nd hand engines. You need to see it working and demand that it is stone cold before he starts it. If the vendor has started it to "just warm it up" walk away and say you will come back another day. I got caught out by going for a test sail/motor in a yacht in which the engine was running as we arrived. Bought the boat only to find it was a pig to start. And that was just the start of two years of problems.
Spares for your engine may not be that available. Any that are will be expensive.
If it aint broke, dont fix it. You may make it worse.

 

[Andrew E]

Is the Bukh 20 @ 20 hp not a bit too big Your MD7a is ony 13 hp. Like others have said be weary of 2nd hand engines. You need to see it working and demand that it is stone cold before he starts it. If the vendor has started it to "just warm it up" walk away and say you will come back another day. I got caught out by going for a test sail/motor in a yacht in which the engine was running as we arrived. Bought the boat only to find it was a pig to start. And that was just the start of two years of problems.
Spares for your engine may not be that available. Any that are will be expensive.
If it aint broke, dont fix it. You may make it worse.

I don't think it is. Infact MD7A is probably a little underpowered for my Griffon Mk I and the Griffon Mk IIs were fitted with 20HP Bukhs.

Re: If it aint broke, don't fix it, you're right but slightly worried my good luck will come to an end.

Definitely going to look at the fuel injector and a friend suggested testing the thermostat. B*gger playing around with exhaust manifolds just yet.

 

[prv]

a friend suggested testing the thermostat.

Good idea. Do you have the specified opening temperatures for it? Pop it in a pan of water on the stove, with a thermometer, and start heating. There should be one temperature specified at which it starts to open, and one at which it's fully open. I did this with my Yanmar and found it had stopped working; the new one wasn't expensive.

Pete

 

[ghostlymoron]

My inclination would be to tinker but it's probably not the right answer. Usually these questions are answered by a new unit. I too would be wary of recon unless you know it's history

 

[cc pete]

I don't think it is. Infact MD7A is probably a little underpowered for my Griffon Mk I and the Griffon Mk IIs were fitted with 20HP Bukhs.

Re: If it aint broke, don't fix it, you're right but slightly worried my good luck will come to an end.

Definitely going to look at the fuel injector and a friend suggested testing the thermostat. B*gger playing around with exhaust manifolds just yet.

Hi I have a surplus new Volvo D1-20 with PRM gearbox , PM me if you are interested , Best Rgds ccpete

 

[pvb]

My inclination would be to tinker but it's probably not the right answer. Usually these questions are answered by a new unit. I too would be wary of recon unless you know it's history

I think it's a question of balance. The OP doesn't want to use "rip off" engineers, which is understandable, but there's lots he can do, simply, himself. If he has money to burn, a new engine would obviously make the boat more reliable. But at what cost? And, if he has money to burn, why not just get a different boat - which might well be the cheapest option? We don't know how badly the OP's engine smokes, whether it's a gentle mist or a full-blown smog alert, but it might not really matter much in the overall scheme of things. My old 2003T smoked when I bought it, and it still smoked when I sold it, 19 years later.

 

[eddystone]

Tom Parker is good but not if you're in a hurry.

 

[PaulRainbow]

The answer here is in post #2. Get the injectors out and take them to a diesel injector/pump specialist. No need to look for a "marine" version of specialist for this job. Have the injectors tested/reconditioned/replaced, as recommended by said specialist.

Do not touch thermostats or anything else until you have done the above.

If it still smokes a bit on startup, live with it and keep your money.