Engine smoke / mechanic required??

[ab1974 1]

I've got a 17hp Volvo diesel in my yacht. Was rebuilt about 5-6 years ago and done about 200 hours since. Is a MD7B (early 80s model)

 

Engine has been blowing black smoke (especially on start up and high revs under load). A little smoke for this model is apparently quite usual.

 

Today the engine took a little longer to start than usual - say 10 seconds rather than 5. Normally gets started once - twice a week. After a sail I turned it on as we came back into the marina. It stalled after about 30 seconds running. Waited a few minutes then started it again. Was OK but seemed down on power and was slow / reluctant to rev. Was blowing more black smoke than usual. Reversed into the berth and put it into forward to bring to a halt and it took much longer than usual to rev up and was very sluggish.

 

I think I might have a fuel / injector issue.

 

Any thoughts?

 

Any suggestions on a decent diesel mechanic that isn't rough and does a good job for a fair $$$.

[PaulR 3]

Where is your boat may help the suggestions happen

Tied up and locked does knot count

[ab1974 1]

Good point, shouldn't post just before heading to bed.

 

Boat is in Westhaven.

[SloopJohnB 322]

Where is your boat may help the suggestions happen

Tied up and locked does knot count

 

 

Do the engine faults vary to where the boat is, i.e.

a boat on a mooring up at Hobsonville, different to a boat on a marina at Westhaven, to a boat on poles in the Tamaki have different problems for a smoky exhaust.

[Farrari 4]

I had a number of issues with smoke on my previous vessel's motor. I used Ian Meikle (027 4192140) and would thoroughly recommend him. He was reasonably priced and new his stuff. He also teaches the small diesel motor maintenance courses for Coastguard from time to time.

 

I have had blue, black and occasionally white smoke out of my previous motor.

 

Blue was from oil burn (in my case from carbonised bore). In my case the solution was reasonably simple. Change the oil & filter, throw some additive down it and most importantly work the motor hard. Ian was able to put his endoscope down the bore and assess the state where previous crowds I had talked too just priced up an engine rebuild!

 

Black was from unburned fuel. I had the injectors done, a new primary fuel filter installed and the diesel bug cleaned out. You can check for diesel bug and change the filter easily yourself if you want too. I would also check your fuel lines for air leaks. Air bubbles in the primary fuel filter bowl are a sure sign.

 

White turned out to be grey and was the start of black smoke with condensation and all it took was a replacement of the fuel filter to fix. From what I was told pure white smoke can be one of the signs that the motor is overheating.

 

Hope this helps.

[Bimini Babe 0]

Just out of interest, anyone know how much it'll cost to get injectors serviced? Does it differ with engine make/size/etc?

[ab1974 1]

Thanks Ferrari, good summary.

 

Looks like your black smoke issue may have been caused by the problem I think I have with the injectors.

 

Would be interested in feedback to BB's question re getting the injectors done. Mine is a 2 cylinder

[Farrari 4]

My injector clean and repair for the two cylinder Yanmar was $160 + GST and 7 hours labour at $60 / hr (3+ years ago). The 7 hours did include a bunch of other work I got done at the same time (Motor Zinc, Air Filter housing leak).

 

My 27HP (3 cylinder) VolvoPenta that I had done about 9 months ago cost $200 + GST plus labour. This was part of a complete engine rebuild so I'm not sure on the labour component.

 

From what I understand some diesels have an injector pump included with the injector and some have a single servicing all. On this basis I would imagine the cost is going to be motor dependent. The number of injectors is also an obvious factor.

 

Hope this helps.

[wheels 543]

Before you get a mechanic in, check a couple of things yourself first.

Black smoke is often considered unburn't fuel. But actually that is not quite correct. Unburn't fuel would come out in tow ways. It would either be liquid diesel, or if heated enough, it becomes white smoke. Black is poorly burn't fuel, due to the absense of enough oxygen to completely burn and the result is Carbon, which is the black.

First place to check is the Air intake. Ensure it is clear. I know that sounds dumb, but I know of an instance of a spider happily bloking the intake up with a web. Then check the air filter if it has one. Make sure it is clean and most especially dry. If it is a paper cartridge type, they will not pass air if they have been wet or very damp for sometime. Then check the intake hose if there is a flexi hose. I have seen them delaminate and block intakes.

Next is to go to the exhaust end. Air can only get into the engine if it can get out. These engiens have a cast Exhaust elbow and they are really bad at blocking up with rust and crud etc. Then check the entire exhaust and ensure it is clear of delamination or collapsed hose etc.

Failing that, the next step is a mechaninc, because they are the more difficult area's if you are not mechanicaly inclined. It can be Injector issues, but sounds more like a timing problem, which is in the Injector pump side. Injectors themselvs could cause a problem, but you don't normally get black smoke. Not saying it can't happen, its just not normal. Grey/White smoke is normally an injector or compression issue. However, if an injector is pouring fuel in,(due to being sticky and not opening properly) then the fuel does not mix well with the air and thus you get unburn't fuel.

You can also try an injector cleaner at a high dose. Just take a small can of fuel and connect to the fuel line. Then pour a can of injector cleaner in and run the engine.

You can also save money if you remove the injectors yourself and take them in for service. Diesel Services or similar is where they go. Ask for a evaluation before repair, so as you can see if it is the injectors or if you have to delve further with the injector pump. If you don't ask for that, they mnay just go ahead and rebiuld them without actually looking at them first. And then you put them back in and find you still have a problem.

Don't try and remove the pump unless you are very mechanically minded. The tinming can easily be got wrong and just one smalllittle bit out and you can have all sorts of issues.

[ab1974 1]

Thanks very much Wheels.

 

I will check the air filter in the morning. Ironically I was looking at an injector cleaner earlier in the week before the problem happened yesterday.

 

I tried to start it today and it took ages to start (probably 10-15 seconds) and then hunted - reving up and down while in neutral with no additional throttle on.

 

I've only a small fuel tank which was new with fresh fuel and brand new primary filters installed as part of the refit. There is about 10L of fuel left in the tank so I might just put the injector cleaner straight into the tank as it will be pretty concentrated.

 

I am wondering if the hunting indicates the one of the cylinders is not firing properly?

[ab1974 1]

Actually the smoke is probably more a dark grey then black. However I am ending up with a black residue on the paint work surrounding the exhaust.

 

The injector cleaner I was looking to use is called FTC. Anyone had any experience. They seem the advertise lot and have lots of testimonials - but it is expensive and wondering if it is 'too good to be true':

 

http://www.neptuneproducts.co.nz/shop/P ... +pack.html

 

Engine exhaust elbow is brand new.

[wheels 543]

I have never heard of FTC. One hell of a claim. 200% money back. I imagine the working additive will pretty much be the same as most of them anyway.

The hunting sounds interesting. If those simple remedies don't help, then it maybe a case of the injector pump itself. I can't think of the injectors causing that kind of problem, nor a cylinder not firing properly.

Sorry, I can only guess from this position.

[Guest]

I have a full workshop manual for this engine (3mb PDF) PM me an email address if you want it. It means you don't have to pay the exhorbitant rate for a Volvo mechanic.

[ab1974 1]

Have bled the engine - that seemed to be the problem with the lack of power and hunting.

 

Still have the grey smoke issue. Took the engine filter off and it is quite oilly, so I will clean it in petrol. New Volvo filter is $250! Ran better without the filter, so hopefully a clean and it will be better.

 

I will stick some additive in the fuel and see if that does anything.

 

Thanks for the offer of the manual Pwederell, have sent you a PM.

[Farrari 4]

AB, my VolvoPenta air filter sounds similar to yours. They are design to be oiled as this provides the particle protection unlike a paper filter. I had mine cleaned and re-oiled as part of the rebuild. I too was scared off the price of a replacement.

 

I would also keep an eye on your fuel system as you normally wouldn't have to re-bleed it unless it has an air leak. I have spent the last 6 months trying to track down the source of an air leak I had. A very frustrating exercise I must say.

[wheels 543]

Have bled the engine - that seemed to be the problem with the lack of power and hunting.

You bet me too it. I ws thinking that very thing today while out and about. Blocked fuel filters, and air being sucked into the fuel line can cause that issue. Make sure you have a good fuel flow.

If you look in the tech "sticky" post, I am pretty sure I posted the manual for that engine in there. I think!

[Noodles 0]

if the fuel system is sucking air in, it needs to be fixed as the problem will just come back. check the fittings are tight and filters on properly. to get the injectors serviced can cost about 3-700$ depending on who you go to. if it is a unit injector (like Detroit) or pump element (like Duetz) can be difficult to find someone who can test and repair them properly.

[ab1974 1]

Thanks Wheels, though not sure where the Sticky post is on the forums.

 

Does anyone know about re-oiling the filer as Ferrari has suggested. The Volvo guys said to clean it in Petrol or Kero, but nothing about re-oiling.

 

Noodles - I had a problem when the motor was first installed with air in the fuel system. Bled it and the engineer re-tightened everything. Hadn't had the issue for probably 15 odd hours running since then. I will check again, but odd that it has happened again.

[Atom Ant 0]

Hey ab1974 - be very careful about cleaning your air filter in petrol. The risk is petrol & or vapours remaining in the filter when you start the engine = revs out of control, and I mean seriously rev until it flys apart type stuff. Surely someone here may say it can't happen but I've seen it happen and it is nasty! If your filter is paper - throw it out and buy another one.

[wheels 543]

Go to page 7 of this Tech Talk forum and you will see one of my posts with a huge list of manual. Scroll down through the list and you will see a the one you want.

 

Atom Ant is correct about petrol causing runaways, but the filter has to be pretty wet. It was a problem in cold climates where the petrol didn't evaporate away fast. I don't think we have an issue with that here.

However, if it is a paper filter, DON'T wash it in any solvent. Use a detergent in warm water. Like say simple green or one of the water based detergents for removing oil and grime. But do not use solvents. And also if it is paper, you do not use oil on them afterward. The filter opils are for use of Foam filters like K&N filters. Which I highly recommend you see if you can find a K&N filter to replace the one you have. Expensive, but you can wash and re oil them. They come with those products. And they willlast you a life time. In fact they would last a life time before they even need to be cleaned in a boat.

Now one thing to check if you have oil all over the filter. Where does the air breather go from manifold back to air intake. If it enters at the filter, that is not good. That is the source of you gunky oil biuld up on the filter. You need to try and introduce it as close to the engine as possible to ensure the oil gets sucked back in to be burn't. It was common for those breather to be introduced back in at the filter, which is a fool of an idea. Must have been thought of by the filter makers.

Re the air in the fuel. You replaced the filters I believe. Where they dirty?? If yes. Then you need to check the fuel lift pump. If it is the long plunger type, then no problem. But if it is the Block mounted round diaphragm type, you need to remove the cover and inside you will find a fine brass gauzze. Carfully remove it and with great skill and care, try and throw it as far away as you can. The real filters will take care of what needs to be taken care of, as long as you replace them yearly. The brass thing is a pain, it blocks and many don;t know it exists and you don't want to be trying to sort that one out again, or worse, while in a ruff sea.

Also check the diaphragm while you are at it, for signs of cracks. Our new Diesel fuel is "dry" to these old materials and they can crack and allow air in, but worse, they can allow fuel into your sump.