Yes I will look into this idea
Best I can tell ringing noise comes from some part of the back of engine anywhere from top where valves are down to the rear big end and or gearbox
Ringing seems to take place engine in gear
or in neutral??
The engine came with boat with this 2006 installed engine when I bought it in December 2019
Then covert 19 shut the boat yards in ireland for two months so could not lift
engine fix the small leak the previous owner told me about and under pressure to let new boats in had too launch with engine leak .
I ran engine for about 20 hours and never saw any signs of any oil leak of any sort or any drop in oil so I figured the problem had gone or the previous owner had got it wrong ??
I took out all the 2 year old oil diesel fuel and binned it and serviced engine
New oil filter ,new oil ,new air filter replaced the broken alternator with suitable grey version 80 amp replaced alternator, new anode on prop but not yet the engine anode I ran engine on land connected to cold water
to not create issues using road diesel fuel and all went well.
The oil leak best I can tell using multiple light sources several mirrors comes from a bolt or nut on the back starboard side of the sump
The oil seems to oooze out around the bolt head
or nut head and drops into the bilges.
@ skipperpete and @compass790
Yes 4 litres of oil in the bilges with some water
hurts the pocket and is messy
I can't swear that the oil is not coming from higher up the engine and works its way down the side of engine but all my checks showed this is less likely but the new clean oil is harder to see.
I found out the hard way where I normally dip the dip stick several times to get a good reading with the first oil alarm I only did two checks and both times different reading one said full and the second came up the normal 1/2 full so thought the alarm was something to do with tightening the alternator belt and started the engine for a few seconds to see if alarm went away .
The alarms on this old style Yanmar panel have no writing on them just four lights and the manual for boat showed another type of panel before I twigged it must be oil pressure light.
Yes got to buy the proper oil pressure kit solutions Yanmar oil low system sucks it tell you where you went wrong when its too late
Rechecked dip stick again several times and found no oil on dip stick
Best I can figure the dip sticks tube can keep some oil in it even when the sump is mostly empty because oil is thick sticky stuff in the dip stick tube and it takes several dips to force residual oil out of the dip stick tube mostly becuase it seems to angle horizontally for the last section of the dip stick.
Yanmars 2ym15 dip stick tubes also suck
@ compass790 and others
Zero oil on DIP stick from taking out remaining oil is about
Half a litre in sump .
Then I refilled the oil again to top mid levels more easy to see any drops in oil which showed nothing had been lost
I ran the engine for half hour triple checked the oil no drop in oil level but after one hour running alarm came on with intermittent switching on off like the first time before it goes full on and switched off engine then.
Multible dips of the dip stick showed again no oil.
I have triple checked the oil filter which is above the leak no signs of issues
The new oil filter I pre oiled rubber gasket
for oil filter before screwing on to not cause gasket
to crumple up and was hand tightened carefully and hard never had oil filter leak on many oil changes of cars and boats I owned
were always full from marina electric
and trickle chargers so normally the alternator will do little to no work and show 13 volts unless I gun the engine in which case when I go back to low throttle the alternator will continue to show north of 14 volts for some time exceeding 15 minutes and probably only supplies less than ~5 amps to battery
for engine which is a normal new ~ 80 amp type for diesel cars .
From memory I think I took the alternators belt off ran the engine but still got the ringing noise.
The problem is If I was at sea I would not worry so much I would have my sails
I bought boat in boat yard on tidal river region with 15 miles of fast river water to get to the sea with no real suitable safe anchorages
and the regular small cargo ships using deep channels on the river
The hazards on the river on the way to the sea means I absolutely need the engine and anchors to work
The engine is under proped best I can tell 12 inch by 9 inch three blade probably the first prop the original 8 HP 1968 engine had and not changed when the 13.5 HP Yanmar was put in in 2006.
Hard to get faster than 4 knots best I can tells with 3.5 ton 30 ft narrow beam fibre glass 3/4 keel
For the river I have to with the tidal current
with the lack of useful power from engine
I should have known there was catch when the first owner said it only uses 1 litre an hour it goes three and half knots on 1/3 gas and four knots on 2\3 gas and brick walls after that .
The fuel delivery
can't come until Monday
I will follow the other advise rig up a small can new fuel and try that trick on Sunday
British and Irish diesel fuel both road with ~7% bio fuel non marked type and heating
types marked are normally made to be 55 for Cetane to my knowledge .
However many truck companies complain the new Irish diesel with Bio fuel is wrecking their engines so that was why I preferred to get the marked stuff in case there is some issue with bio fuel lubrication qualities or Cetane level issues of road diesel .
Most diesel engine were built before bio fuel regulations
Bio fuel issues have wrecked many diesel engines not originally made to run on bio fuel including some marine
Bio fuel Cetane levels drop when heated up in inline injector and then can return to tank the heated fuel several times when engine run at low speeds so some diesel fuel experts claim.
More simplex 2006 Yanmar 2ym15 engines can probably run on kero bio fuel and bio fuel mixed with petrol (gasoline Benzene ) but should run best on pure diesel which can still be bought in some parts
of the communist controlled EU who brought in against transport companies advise the 7% bio fuel regulations costing billions in broken diesel engines mostly turbos and high pressure pumps and injectors .
The old style pre 2000 diesel engines are mostly tolerant of bio fuels
Another forum suggested hot carbon deposits can be igniting the fuel too soon and causing knock but I thought that was something that only happened to spark ignition petrol ( gasoline Benzene ) engines ??
Any ideas on that possibility ??
It isn't unknown for some fuel suppliers to cut the diesel fuel with high kero contents at 40 cents a liter for kero and 60 cents a litre for marked diesel on a forty five litredelivery that can make a few extra sponduliks along with the delivery
charge of 30 extra cents per litre .
How ever in this case if the kero content is too high I don't think it was intensionally done to save a few cents on 45 litres but who knows ??
I know one friends 1990 type Toyata Carina non turbo 2 litre diesel that went 200,000 miles using home heating kero no ill effects.
However well old type primitive diesel engine can run with pure Kero its a high temperature fuel burn with low lubrication qualities unknown Cetane and can reputedly diesel experts say can grill
a modern inline injection type diesel engine with a Turbo and its high pressure fuel pumps in no time.
Modern diesel engine can with suitable modifications be made to use Kero and is seen in use mostly in electric power generators
I too am confused why I got belt screech when I tightened the belt and it went away when the belt was loosened up the belt again .
Because the battery
is new and 80 amp alternator and mostly fully charged the alternator won't drag so much and supply very few amps .
I will check why that happened another post another time .
Thanks for all your inputs it gives me more possibilities