Author Topic: White smoke from exhaust (Read 13587 times)

Vinnie45 · « **on:** June 20 2018, 12:28 »

Where I took my 2007 Bav30 on her maiden run this year I am seeing white smoke coming out . I cannot replicate in neutral only when in gear . Can anyone tell me what I should I look for in order to triage the issue . Thanks

Yngmar · « **Reply #1 on:** June 20 2018, 13:24 »

Might be steam from lack of waterflow through the heat exchanger. Cause would be a restricted waterflow, so check strainer, impeller, hoses, intake (saildrive leg can foul up inside from lack of use) and heat exchanger tube stack, in that order.

IslandAlchemy · « **Reply #2 on:** June 20 2018, 13:27 »

What he said

Vinnie45 · « **Reply #3 on:** June 20 2018, 14:41 »

Thanks

sunshine · « **Reply #4 on:** June 21 2018, 12:38 »

As Yngmar says, but also check the exhaust elbow for carbon build up or corrosion restricting the flow. Take the exhaust pipe off and use a phone camera to take pics up the hole to look for blockages, and also stick a finger up to probe around. Its pretty easy to take the elbow off for a more detailed exam, but you'll need a fresh gasket to replace it.

Brian · « **Reply #5 on:** June 21 2018, 14:26 »

If you still cannot find the answer then the next step is to get your injectors checked, the white smoke could be unburnt diesel. This happened to me and I believe was caused by poor cooling causing the engine to run hot, leading to damaged injectors.

Vinnie45 · « **Reply #6 on:** June 21 2018, 23:58 »

I had my mechanic onboard today with no new results . He replaced the seal around the impeller, it seems Volvo change the seal for a new one and did send the old model . He checked the heat exchanger where he said he could put his hands and either end meaning it was not that hot. The coolant was fine and the engine started fine . However when we reved to about 2500 it started to smoke again ? We added new diesel to the tank . The mechanic said he would be back in a couple of weeks to some sort of system where they use chemicals in the engine to breakdown calcium buildup. The mechanic said use the boat at a lower rpm , others have said go out and run the boat hard ? I may call another mechanic more familiar with the Penta ? Any other ideas like where would I look for calcium buildup , can I remove any hoses , when it runs it just sounds like the muffler is loud. Thanks

KiwiBeanie · « **Reply #7 on:** June 22 2018, 00:48 »

How much water discharge do you have from the exhaust? It should be a decent amount every second or so, not necessarily a constant stream, but a good plonk when it does come.

Does the smoke dissipate quickly? If so could indicate that it is steam rather than smoke.

If it is insufficient water flow then try a poking a long piece of stiff wire down the raw water intake to clear any blockage from sail drive intake.

IslandAlchemy · « **Reply #8 on:** June 22 2018, 08:12 »

It'll be the water intake. Take the inlet pipe off at the seacock and see what the flow of water is like. It should be like a fountain.

If it's more of a dribble, then you have a blocked leg (any mechanic worth his salt would have done this FIRST!

Put your dinghy pump hose over the barb fitting and get someone to stamp on the pump half a dozen times to blow any crap back down and out of the leg.

Then see how much water comes out. If you now have a fountain, you have solved the problem.

Salty · « **Reply #9 on:** June 22 2018, 10:07 »

The waterway within the saildrive leg is a favourite home for mussels and other marine organisms which once they have taken up residence are a devil to clear. The waterway has a bend or two in it such that it is not simply a matter of poking something down it from inside. Every lift out I make a point of jet washing through each of the water inlet holes, and have a set of long bottle brushes to help persuade all squatters to find alternative accommodation. A problem with mussels is they have two shells which will remain securely attached even though the original occupant has deceased or left home. Sometimes those shells become detached and on my B36 (2002), the cooling water filter is of a particularly bad design such that it is possible to put the filter back after cleaning and get it wrong to the point that these shells can get past. From there they travel through the cooling water pump and end up congregating at the entrance to the heat exchanger. On one occasion some 70 to 80% of the heat exchanger tubes were blocked, and a high temperature alarm sounded and externally, steam was visible in the exhaust. Fortunately for me I’d recently changed (at the time) the Volvo alarm panel, and the new one actually worked and warned me of the problem. On that occasion I connected a mains water hose to the connection on the inlet valve and let it run for ten minutes to try to flush out the incumbents. Since then I’ve fitted an exhaust temperature monitor and alarm system (about £100 from Nasa), and it’s brilliant where any increase in cooling temperature is immediately visible on screen, and an alarm will sound should the temperature exceed your preset limit.
If your boat stays idle for long periods, it’s odds on that the nice cosy waterway within the saildrive will become a new housing estate!!

Vinnie45 · « **Reply #10 on:** June 22 2018, 11:35 »

In US a lot of mechanics are not savvy on saildrives . What you all say sounds totally logical that has been my biggest fear all along. The amount of growth around the intakes every year has been enormous , this year I added formaldehyde to the paint . The smoke is like steam . Now that I have a specific task to ask to be done it may be easier to find someone to do this blow out the saildrive . I will keep you posted thanks for the help

Mirror45184 · « **Reply #11 on:** June 24 2018, 04:22 »

Launched 2007, if the exhaust elbow has nor been replaced I would be starting there. They do get a large build up of carbon which blocks the slot where the cooling water is injected into the exhaust gas. It is not always obvious where this is if you have not seen a new one. The exhaust elbow may have also corroded which wold mean that the water does not mix properly with the exhaust.
Replaced the exhaust elbow on my 2009 B40 in 2016. Similar issues for a while which eventually also became a loss of power! DSCN1129 is the new one looking up the outlet end, you can see the water slot. DSCCN1126 is the old one no comment needed!
There is a supplier in the US who fabricates stainless steel ones as an option.
Cheers

Lyra · « **Reply #12 on:** June 24 2018, 12:00 »

Another place to look for this problem (although less likely since you say it happens only in high RPM) - check the coolant level - if it drops over time you may have a leak of coolant into the cylinders.

Vinnie45 · « **Reply #13 on:** June 24 2018, 17:12 »

I replaced the elbow last year. The mechanic said coolant was fine. When trying to find blockage in the sail drive , do I hire a diver to go below the boat or when I remove the thru cock from above is that sufficient ?

IslandAlchemy · « **Reply #14 on:** June 25 2018, 08:11 »

No, just take the pipe off on the inside, where it connects to the seacock, put the dinghy hose onto the seacock stub and then pump like crazy. This is easy to do yourself. You don't need to pay a mechanic to do it.

Vinnie45 · « **Reply #15 on:** June 25 2018, 12:24 »

Ok I will give it try , I hope I don’t sink the boat

Salty · « **Reply #16 on:** June 25 2018, 15:40 »

Quote from: Vinnie45 on June 25 2018, 12:24

Ok I will give it try , I hope I don’t sink the boat

Not much chance of that, the inlet valve on the sail drive is not very far below sea level, so the water will just run in gently at best and down to a dribble or nothing at worst. If things start to get out of hand you just shut the sea valve.
Very handy though to have a redundant wine bottle cork to hand as a “just in case,” and a good reason to drink a bottle of wine before you start the job 🤪 !!

PEA-JAY · « **Reply #17 on:** June 25 2018, 21:59 »

How about blocking the underwater inlets (fins both sides and hole) suck up or pump out water and filling overnight with white vinegar (neat). It will dissolve all marine growth. If you manage, repeat exercise twice. You will hear a lot of gurgling while the job is in process so it will be opportune to celebrate with some whisky while the vinegar gobbles up the pesky barnacles! I successfully cleaned my sail drive this way while on the hard. It might be a little more difficult while afloat but I’m sure it’s possible. Good luck!

Vinnie45 · « **Reply #18 on:** July 12 2018, 00:14 »

Ok I have tried everything . Now someone has told me I should adjust the valves . I went to the manual and it left blank every 500 hours to adjust valves . I went online and could find no videos or information of what to do . Can someone tell me what are the valves and what needs to be done .
Thanks ignorant Vinnie

Ricd · « **Reply #19 on:** July 12 2018, 17:12 »

Hi
Does the white smoke roll over the surface of the water? Does it have a smell (light) smell of sulfur? If yes its possibly incomplete combustion of the fuel due to poor injectors. I had a white smoke issue at revs with my MD2020 when its was around 13 years old. The issue was the injectors. I drew all three and took them to City Auto in Plymouth, a local Bosh car center, who tested them and confirmed injector pattern was poor. They ordered new nozzles, cleaned up injector body, re-set new nozzles and returned them to me with new copper washers in 48hours all for £150. I put them back in and problem solved, no more white smoke and engine running smooth.

Salty · « **Reply #20 on:** July 12 2018, 19:29 »

On the other hand, I spoke to an engineer at the yard where my boat is laid up over winter, as my MD2020D is 16 years old and I was concerned that the injectors might need cleaning or adjustment, and his words were “if there’s nothing obviously wrong, then leave them well alone as fixing them often resulted in more trouble than was there before.” So I left well alone, but then I don’t have any white smoke. But they did adjust the valve timing (tappets), and the engine runs very smoothly.

Vinnie45 · « **Reply #21 on:** July 12 2018, 20:34 »

What does it mean to adjust the tappets ? I don’t even know what part it is or instructions how to do it.

Salty · « **Reply #22 on:** July 13 2018, 04:37 »

Quote from: Vinnie45 on July 12 2018, 20:34

What does it mean to adjust the tappets ? I don’t even know what part it is or instructions how to do it.

Vinnie, on the top of your engine there should be a black plastic screw top cap that you take off whenever you want to add some more lubricating oil. This plastic cap fits into a long green cover that runs in a fore and aft line along the length of your engine top. Underneath that cover (rocker box cover) are the valves and valve operating mechanisms that look like the drawing in the first photograph below taken from an engine workshop instruction manual. A rotating shaft within that cover causes metal arms (rockers) to rock up and down. When those arms move down they press on the tops of the valves, (tappets), causing the valves to open for a very short period of time to allow air to be drawn into the cylinders or exhaust gasses to leave. Adjustments can be made as shown in the wording within the photo.
If you have not actually seen an engineer make those adjustments, and from the questions you have asked I’m guessing you have not, then I cannot stress highly enough that you should leave them alone and ask a qualified engine mechanic to check them for you.

Ricd · « **Reply #23 on:** July 13 2018, 10:58 »

Quote from: Salty on July 12 2018, 19:29

On the other hand, I spoke to an engineer at the yard where my boat is laid up over winter, as my MD2020D is 16 years old and I was concerned that the injectors might need cleaning or adjustment, and his words were “if there’s nothing obviously wrong, then leave them well alone as fixing them often resulted in more trouble than was there before.” So I left well alone, but then I don’t have any white smoke. But they did adjust the valve timing (tappets), and the engine runs very smoothly.

I think your engineer is wrong. If the injector spray pattern is not right you get incomplete combustion resulting in white smoke so something is obviously wrong. The engine will not necessarily run rough either, mine sounded fine. Adjusting the tappets will not help. Pulling the injectors is a very simple task (30mins) similarly re-instating them with the correct new nozzles/tips (c£40 each) and fitted onto the reconditioned injector body with a new copper washer seal, is straight forward. How can this result in more trouble?

Vinnie45 · « **Reply #24 on:** July 13 2018, 12:48 »

Thanks for the information . You are right where I would never try to do it as my boat would never be the same again. I will try to find a mechanic who has the knowledge. Thanks again