Mahe 36: Engines

[Jef & Marin, Netherlands]

Lonnie
First idea would be air in the fuel line. However, could it be that you had switched off the engine electrically while it was still running? That happened to me on a previous ship. Don't kno whether the same could happen on the Mahe.
Regards,
Jef

[Jef & Marin, Netherlands]

Lonnie, I tried to read your email carefully to find out whether both engines had the same problem. Thing is that (on our Mahe 88, Volvo Penta D1-20 engines) the two engines have nothing in common, the fuel filter, diesel pipes, etc are all separate. The only shared things are the plastic fuel tank, the diesel filling pipe and the diesel fuel inside, and the breather of the fuel tank. The breather is at the front of the tank. So is the problem in one or both engines?
Regarding an injector: if one injector fails, why would RPM drop so low as 1000? You lose 1/3 of the power.
Good luck,
Jef

[Scott730]

Jef
I sent Lonnie an email regarding the problem and he is having it with only the port engine. He is out of email range for the next day or so, so he can't respond. Air in the line could be the cause, but the problem started before he changed or cleaned any of the filters so how could the air get in the supply line unless a connection came loose, possible. You make a good point on RPM's dropping to 1000 if one injector is clogged. Can't think of anything else except bad fuel, but that would cause both engines to act up. I hope he finds the problem.
Thanks for the info on the water lines, I'm trying to install a watermaker and have to tee off one of the lines for backflushing, I purchased some 15mm line made by Whale, they use push on fitting, I hope they are compatable.

Scott

[jean1146]

Iriecat. Another thought worth looking at. On our boat I had noticed that after several hours of motoring,everytime I would open my fuel tank,as I started to undo the fuel cap I would here a suction noise,which meant that my tank was running out of air.If you check under the bridge deck the Tank vent is right there,mine was completely plugged up with salt,I do believe eventualy it would have starve the injection pumps.Worth checking.We will be heading for the Bahamas in early April,for 2 Months so I want to hear your stories.
JC. .

[IrieCat]

Thanks for filling in for me Scott. We just got back to internet land. JC, I removed the screen fitler you are talking about just before I left Green Turtle headed for Nunjack. The trip is about an hour or so but I had no problem on the way up. Then I ran the engine a while at anchor and it was fine. Then today we motor sailed back to Green Turtle, again no problem. I can't understand why it only affected the port engine. Then maybe Scott was correct and it was the injector and cleared itself. Jef, thanks for your help also. It does not make alot of sense. Who knows? Anyway, we head for Great Guana tomorrow AM via Don't Rock. I can't remember if there is a wireless signal there or not. If there is I will update you.
Thanks,
Lonnie

[Jef & Marin, Netherlands]

Lonnie, what happened on a previous boat was that we had switched off the electrical switch to the engine by accident (using the engine key). The electrical fuel pump then does not work, and the diesel fuel pressure to the high pressure pump is then decreased. The engine will keep running since the high pressure pump is able to suck the fuel up, however now and then the fuel pressure drops, leading to engine RPM's dropping and coming back, just as you had. I panicked (this was a monohull having one engine only, a serious design drawback, no spare engine) and started ringing up the owner of the boat, a friend of mine. After the phone call I noticed the engine switch was off, switching on solved the problem, and I had to phone him again. Feeling silly. He then told me he had done exactly the same....
Don't know whether the same thing happens on the Mahe having this version of the Volvo control panel.

[IrieCat]

Thanks Jef, I researched that possibility and I think that the pump is not electric. It turns out that the port engine will run all day at 2000 RPM's with no problem, but if I push it to 23 or 2400 it will start acting up. The starboard engine is still fine. Scott, do you still think it could be the injector? I am in Marsh Harbour now and will soon have to get a PRO. We plan to head for Eleuthera as soon as this is fixed. Thanks for the help.
Lonnie

[Scott730]

Lonnie
It sounds like your starving the engine for fuel somehow, Since it's running fine at 2000 RPM and below you have enough fuel for that load so it has to be a component in the fuel delivery system that can't handle a load greater than 2000 RPM's, it could be a dirty injector (sometimes they clear themselves). I put a call into my Volvo Tech that has serviced my boat, when he calls me back I'll ask his oppinon. Hang in there.

Scott

[kev&jo]

Lonnie,
I agree with Scott sounds like fuel is being starved under load, try bleeding the fuel lines by, cracking the nut which joins the high pressure fuel line to the injector, get someone to turn over the engine and after you have seen fuel spill out of the joint, re-tighten. This procedure has to be done three times, each injector, do not try to do them all at once!

Hope this helps and cures the problem!

[IrieCat]

thanks, i will try that. i lleave for eleuthera in a day or two, thanks!
lonnie

[Scott730]

Lonnie
My Volvo tech is on vacation, I'm still trying to get his advice. Let me know if bleeding the injectors helps. We're should be leaving for the Bahamas by the 15th.

Scott

[Scott730]

Lonnie
Spoke with my Volvo guy and he doesn't think it is an injector. He suggests you check all your connections on the fuel delivery system including the bleed screw (don't over tighten this or it will break off) at the priming pump. Also, from the fuel filter to the fuel lift pump make sure the line is in good shape (not collapsed). If everything is in good order, then he thinks you have a faulty lift pump. It is hard to say without checking the pressure on the fuel line. Not good news if it is the pump, you'll have to comeback to have it fixed, no suppliers out in the Bahamas.
Scott

[pguillemin]

Lonnie
Sorry for late answer.
First there is a Volvo dealer in Nassau .They are OK and carry some parts
I would start by checking as recommanded by Scott the fuel lines ( as well as the return .Look like you have some blockage between the tank and the lift pump( could be a particule moving back and forth in the fuel line like a piece of gasket or rubber)
Also look if there is not something pinching your fuel line by the filter in the cockpit lazarette.
Last make sure that there is air coming to the fuel tank
Happy New Year to you all on the forum

[Wayward Wind]

Guys, I also have the Volvo Penta D1-20 engines. For a while, I could not get the engines to go past 2000RPM on port and 2200 RPM on stbd. Recently, I dived and cleaned the props which had all sorts of growth on them, including very stubborn barnacles. Since then, I can get the port engine to reach 2500 RPM, and 2600RPM on stbd. However, the Mahe manual says the 2500RPM is cruising speed, and they should be able to reach 3000RPM. What is the highest you guys can get on your DI-20s?

JohnC

[jean1146]

Johnc.
I cruise@2300 usually,but I have had them running @3000 for short period of time. I have a diver who comes once a month to make sure that my props stay clear,here in Florida during summer month the growth can be a real problem.
JC.