Penta md2020

[patryk221]

Hi I'm new to these engines and jeanneau boats, have bought a jeanneau 29.2 with a volvo penta md2020 engine sounds right revs and motors well until I need to give it more power all of a sudden then I notice diesel being spat out through the exhaust is that normal? ,injectors were serviced and cleaned all filters changed, engine runs well, has enough power in high and low revs, it's only when you suddenly apply more throttle for instance into reverse when approaching a mooring etc, 

[sitara]

Hi Patryk,
Welcome to the forum.
The 29.2 is a great boat - I had one for a few years and then went to something bigger. Mine was equipped with a 3YM20 Yanmar and I never had the problem you describe.

It sounds as though you are getting a momentary overload. When you say diesel being spat out is this as black smoke or a white mist or solid fuel? Also, what sort of prop do you have on the boat? Do you get any exhaust smoke when motoring normally and if so what colour?

Cheers
Rob

[patryk221]

Hi thank for the reply, no it's solid fuel in the water, black smelly smoke but only when you overload it all of a sudden, otherwise no smoke when motoring or idling, one thing I have not changed is the air filter, I have only washed it, might try and see what happens if I take it off

[patryk221]

Re prop its a three blade fixed prop

[sitara]

Hi Patryk,
I don't like the sound of solid fuel in the water. The black smoke suggests the engine is overloaded which is strange for a relatively powerful motor in a light boat.

The fixed prop suggests to me that it is the original and should be appropriate for the boat, so it should not be overloading the system. This can be checked by seeing if the engine will rev out to maximum revs (or close to it) when under load. The 20 hp engine is more than powerful enough for a boat of that size (some of the 29.2s were fitted with 10 hp Yanmars). Good idea to check the air intake filter, also check the exhaust/seawater mixing elbow where the exhaust comes out of the engine and seawater is added. These can block up with salt and gunge.

Solid fuel in the exhaust water can only be coming from the engine via the exhaust system which suggests there is excess fuel in the cylinders which will do them no good. It may be a good idea and cheap insurance to get a good diesel mechanic to give the engine a thorough check. The Volvo engine is a very good piece of kit and will give many years of service if well looked after.

Hope this helps, Rob

[patryk221]

Thnx for the advice, any idea what the revs should be when under load 2700rpm I'm getting

[sitara]

Hi Patryk,
Check the Volvo Penta website for manuals etc. at www.volvopenta.com/volvopenta/global/en-gb/marine_leisure_engines/parts_service/publication_search/pages/publication_search.aspx. You can download the owners manual here and the troubleshooting section should be of some help.

It looks like maximun rpm for your motor is 3600. You should get max rpm with no load. Under load max rpm should be close to 3600 rpm. Just one word of warning - if you cannot get 3600 rpm under NO load check the rev meter for accuracy before spending time and money on the engine.

On my current boat (with a Yanmar 3YM30) max rpm is 3600 and I was only getting 3200 rpm with the factory fitted prop. My mechanic was unhappy with this and wanted the engine to rev out to 3600 rpm under load - as he said, if you don't get max revs under load then you don't get maximum power out of the engine. I have since fitted a feathering prop (Autostream) which has made a huge difference to sailing performance. Speed under motor has reduced but there are still some tweaks to be made to the pitch setting.

[patryk221]

Iv noticed anything over 2700 rps and you can feel the vibrations on the hull so I prefer not to open it up fully, these boats are so thin that you can fell the engine vibrate, will double check it on  the load this weekend and update....

[rene460]

Hi Patryk,

Generally being able to feel the vibration like that is an indication of something wrong, I would not be too quick to dismiss it as a thin hull.  First thing to check is alignment, then check for propellor damage or even a bent shaft.  It all sounds worse than it is, but means lifting out.  Propellor damage or bent shaft will show up quite quickly in cutlass bearing wear.

As Rob says, the motor should give its 3600 rpm or even 5-10% more at full throttle if all is right with the propellor.  My experience is that even a single barnacle on a blade well out from the hub has a dramatic effect in overloading the engine so it will not reach full revs.  Remove the barnacle and normal performance is restored.  Worth a dive, or hire a diver to check it before you lift out.  I believe a bunch of barnacles or minor propellor damage would cause plenty of vibration as well as loss of performance.

You will enjoy your sailing when you have it sorted, so keep at it.

rene460

[patryk221]

Rene

Vibration is not major but one does feel it a bit, I guess at the end one is standing ontop of the shaft and engine in reality   boat has been out of the water Prop and shaft are fine, have noticed in the allignment that its slightly missaligned, Im talking like 0.5mm but its nearly impossible to get it 100% all around the shaft... Iv never owned a Jeanneau have only sailed old 1980s boats which are heavy if you compare it to the Jeanneau I own now, so I have nothing to compare it to, to see if that is normal or not...

[sitara]

Couple of more points - is the cutlass bearing OK? - too much play can cause vibration. Also have you tried revving the motor out under no load? - if you increase revs slowly you may find points where the motor itself has an inbuilt vibration.

Modern engineering techniques are allowing designers to build boats that are light and very strong. Strength of hull was certainly not an issue with my SO29.2. Running the engine out to max revs under load will make a lot of noise and vibration, but you only need to be at max revs for a few seconds, and then you will know how well the prop suits the motor.

You have a great boat.
Rob

[patryk221]

Cutlass is brand new Im a fussy bugger... will do some tests this weekend

Sitara:  what do you mean by "but you only need to be at max revs for a few seconds, and then you will know how well the prop suits the motor."

[patryk221]

Re boat no doubt I have a great one   reached 7.4 Knots the other day and thats without the tide pushing me, so cant complain there

[rene460]

Hi patryk,

Question on is, why is it brand new?  It is the condition prior to replacement that tells a story.  It will be interesting to see what the weekend tests show.

rene460

[patryk221]

Rene, yes Rene I bought the boat last year and the previous owner knew nothing about the boat, has run it with the engine misalligned and the Cutless was gone on it, so I have replaced it and alligned the engine (well tried to)

so to sum things up

Run the Engine under power see what  RPM are achieved
Run the engine in neutral see what  RPMs are achieved
See when slight vibrations start

[ianqv]

Hi Patryk

Welcome to the forum. Its v friendly here and a mine of information!

Re the diesel coming out of the exhaust.
Can I ask why were the injectors serviced? was it for this concern? or another?
If you are getting unburnt fuel coming the exhaust... it can only be for a small number of reasons.

Poor compressions - the fuel is not being burnt. However you say the engine runs ok.
The other top suspects are injectors (which have been serviced) or the F.I.P (fuel injection pump).

I'm wondering if one of your compressions may just be borderline, enough to run the engine, but not enough to deal with a sudden demand of power.
They are easy to check, so may be worth doing. Sorry I don't know the spec off the top off my head.... but it should tell you in your manual.

Perhaps another thing to check is to see if you are loosing coolant (even if just slight).
Possible head gasket if you are. But doesn't sound like a likely candidate as you say the engine runs well at all other times.

What would I do....
Check coolant
Check compressions
If the above are good - call an engineer, or
get your fuel pump and injectors checked out (your injectors injectors will be out anyway! at least the injection specialist will be able to couple your injectors up to your pump).

Another question.... what does she start up like from cold? much cranking? or on the button? any smoke? if so, what colour? and does fuel come out of the exhaust?

Best Regards

Ian

[patryk221]

Hi Ian

I got the injectors serviced because of the concern, been told thats the first thing to start with

Another question.... what does she start up like from cold? First time as if the engine was new no cranking at all and no smoke  if so, what colour? and does fuel come out of the exhaust no fuel out of the exhaust, it only happens when I yank her into reverse or suddenly put the engine under load, then grey smoke and obviously diesel...

Have changed all filters at this stage and added a new Truck air filter will be testing her this weekend, the only thing I havnt checked so far was the exhaust elbow...

Will be testing this weekend keep you all updated

Thanx for all the suggestions

[ianqv]

Hi Patryk

Hmmmmm the plot thickens!!
I'm scratching my head here!
The fact that she starts up so well would not indicate low compression/s.
An exhaust elbow could be it, but you may not get max revs if that was clogged up!

I guess number 1 suspect has to be fuel pump!
Really clasping at straws here.... is your pump and cam belt driven?
If it is, I wonder if your pump timing could be out (wild guess I know!)


What ever happens, please please keep us posted!!

Best Regards

Ian

[patryk221]

Ok after testing this weekend here are the results: 
in neutral 3100 rpm under load 2700 seems to me like its probably the governor restriction so would have to take it off and try again, unfortunately she still spits diesel if one forces her into reverse all of a sudden with some grey smoke. new filter didn't fix it...

she does start first time with no issues as if it was new even from cold, does not miss a single beat when under load...next thing to check I guess is the exhaust elbow then if that does not work light a match am slowly running out of solutions...

[sitara]

Hi Patryk,
Revs under no load does not look right to me. Either not enough fuel or air for the motor to rev out, but new filters so that is unlikely or a partial blockage in the exhaust mixing elbow. If not these time to call in the experts.
Good luck
Rob

[patryk221]

Will check the exhaust elbow on Thursday then as u said call it a day by calling a Pro or just living with it

[patryk221]

Taken the restriction off the governor today in neutral 4000rpm under load 2700rpm black smoke diesel in the water,... Maybe I should get the injectors checked again, she runs smoothly starts the first time....

[sitara]

Do you know the diameter and pitch of the prop? My 29.2 had a big two blade but I don't know what the size was.

[patryk221]

need to wait 4 months to get the diameter when she comes out of the water oh well exhaust elbow next then I will wait till shes out...

[patryk221]

Taken exhaust off today, few flakes inside and rust, have around 25mm hole in there , it's rusty bit it seems plenty of space for it to breathe, don't know how a new one would look if anyone knows pls let me know, what I did notice is the top piece where the water comes into the exhaust to cool it was partly blocked 5mm now I have a 10mm hole so hopefully it's that, will put it on next week and test, Then give up