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28-03-2020, 16:20
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#1
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Registered User
Join Date: Mar 2020
Posts: 3
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Engine problem
I have a Thorneycroft 80D engine on my yacht, basically the same as Westerbeke K4. I had start problems earlier this year so when we hauled I had the injectors serviced, four new nozzles, cleaned the fuel tank, replaced the rubber ‘O’ rings of the injector pump delivery valves. Tested the engine and all seemed ok. When we were launched the engine ran till we were ready to leave the cradle then stopped and refused to restart. We hauled out again and started checking the system.
There was air getting in so all low pressure hose and connections have been remade, filters changed along with their rubber seals. The engine runs for 10-15 minutes and stops, it will not start again immediately unless I bleed the injectors then it runs for a few minutes and stops again. If I leave it till the next morning it starts fine but again stops after 10-15 mins. I eliminated the tank by running from a can of clean diesel same thing happens again. I am now at a loss as to what it can be. I cannot get an engineer in or buy parts or get parts looked at as we are in lockdown due to Coronavirus.
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28-03-2020, 16:49
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#2
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Senior Cruiser
Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 49,085
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Re: Engine problem
Greetings and welcome aboard the CF, Philtadd.
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"
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28-03-2020, 17:27
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#3
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Moderator Emeritus
Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 31,351
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Re: Engine problem
Look up Diesel loss of prime on the Internet, that should give you some trouble shooting steps to take.
But suspect everything before the low pressure pump and even it actually.
If you have access to clear vinyl hose, sometimes putting in a piece will let you see if any air is getting in, then keep moving the piece of vinyl hose towards the tank until the bubbles go away.
Of course clear vinyl is not acceptable for fuel hose, but just for trouble shooting it’s OK in my opinion
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28-03-2020, 17:48
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#4
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Moderator and Certifiable Refitter
Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: C.L.O.D.
Posts: 20,242
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Re: Engine problem
Quote:
Originally Posted by Philtadd
........ I eliminated the tank by running from a can of clean diesel same thing happens again. I am now at a loss as to what it can be............
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Was the can of diesel gravity fed directly to the injector pump i.e. did it bypass the lift pump?
If you did not gravity fed it, try that to help determine where the problem lies. If it runs OK in one spot, keep moving the can back until the problem area is isolated.
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
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28-03-2020, 19:31
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#5
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Senior Cruiser
Join Date: Oct 2007
Location: 29° 49.16’ N 82° 25.82’ W
Boat: Pearson 422
Posts: 16,306
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Re: Engine problem
When you have a persnickety air leak in a diesel system like this you can spend hours and hours trying this and that and, you might get lucky and find the right bit or you might not. Been there done that.
The best way for me to find and diagnose one of these is to start at one end of the system and work my way back. Meaning:
Get a very clean container like a small fuel jug or even a plastic bottle and fill it with clean, fresh diesel. Get a new, clean piece of fuel hose, drop it in the jug and connect the other end to the input side of the secondary filter IE the one on the engine block just before the injector pump. Make sure the hose is full of fuel and is submersed in the fuel in the jug. Crank engine and run for a while. If it runs then the problem is farther upstream, if it doesn't then you have found the area with the problem. There would be a leak in the secondary filter or the lines to the pump or the pump itself.
If the engine runs at step one then move back to the next point in the system, connect the jug and run the engine again. Keep moving upstream in the fuel supply system until you reach a point where the engine sucks air and you have isolated where in the system you have the problem.
__________________
The water is always bluer on the other side of the ocean.
Sometimes it's necessary to state the obvious for the benefit of the oblivious.
Rust is the poor man's Loctite.
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28-03-2020, 20:27
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#6
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Moderator
Join Date: Feb 2010
Location: Australia
Posts: 3,223
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Re: Engine problem
Hey Philtadd, does your fuel return line go back to the tank or only into the top of the engine mounted CAV filter. If the line returns to the tank, read no further but if its at a dead end on the top of the filter housing then the engine has no hope of expelling any air that occurs anywhere in the entire fuel system, even from your newly serviced injectors.
Most engines now are self bleeding from a fitting in the supply pressure line between the lift pump and the injector pump, often with a check valve to stop drainback and to maintain case pressure.
A64pilots wise suggestion of a length of clear plastic hose is the best easily available diagnostic device for suction leaks.
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28-03-2020, 20:37
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#7
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Registered User
Join Date: Jan 2012
Location: Long Island, New York
Boat: Beneteau 423 43 feet
Posts: 850
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Re: Engine problem
And don’t forget to check the fuel pump..... remember there is a filter screen inside that can get blocked....
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29-03-2020, 16:54
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#8
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Registered User
Join Date: Jan 2008
Location: SF Bay Area (Boat Sold)
Boat: Former owner of a Valiant V40
Posts: 1,141
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Re: Engine problem
Had a similar issue. Turned out my emergency fuel shutoff had inadvertently gotten nearly completely closed. Engine would run on the fuel in the filters, then starve. Fuel would slowly refill the filter and it would run again for a bit.
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29-03-2020, 23:02
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#9
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Registered User
Join Date: Nov 2013
Location: Slidell, La.
Boat: Morgan Classic 33
Posts: 2,845
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Re: Engine problem
Sounds just like a blocked tank vent, but since you've run it from a jar, that's out.
Did you use the tank return when test running from the container, or return to the to the container?
Is it possible there's a blocked fuel return line?
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30-03-2020, 01:43
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#10
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Registered User
Join Date: Dec 2019
Posts: 169
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Re: Engine problem
Engines cuttig out is normally caused a smalll hole that lets air in and diesel out. Put kitchen on the fuel lift pump, all of the connections iand filters. Run the engine and you you will find where the leak/leaks is/are.
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30-03-2020, 01:54
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#11
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Registered User
Join Date: Jul 2019
Posts: 30
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Re: Engine problem
check the parts that you replaced for air leaks ie miss seated orings etc
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30-03-2020, 17:25
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#12
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Registered User
Join Date: Mar 2020
Posts: 3
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Re: Engine problem
Thanks everyone. It does not appear to be an air leak, more like a fuel cutoff. Taking the fuel cap off ensures that is not the tank breather, running from a clean can of fuel shows that it is not a tank blockage. The Angliech mechanism on the fuel pump which allows over fuelling for startup is working fine. The electric fuel pump has no filter and ran fine yesterday for half hour of circulating fuel through the filters and back to the tank. Looks like a blockage after 10-15 minutes at the injector pump but when I restart the engine it runs for another 5 mins. Maybe something is moving in a hose even though they are new. The search goes on!
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30-03-2020, 17:33
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#13
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Registered User
Join Date: Jan 2008
Location: SF Bay Area (Boat Sold)
Boat: Former owner of a Valiant V40
Posts: 1,141
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Re: Engine problem
A fuel-line vacuum gauge such as available on Racor filters can help with diagnosis, especially if you have rubber hoses which might collapse.
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30-03-2020, 23:21
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#14
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Registered User
Join Date: Nov 2013
Location: Slidell, La.
Boat: Morgan Classic 33
Posts: 2,845
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Re: Engine problem
Did you use the tank return when test running from the container, or return to the to the container?
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31-03-2020, 01:05
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#15
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Registered User
Join Date: Mar 2020
Posts: 3
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Re: Engine problem
I would have run the spill pipe back to the container, the electric lift pump can shift a pint in 20secs. There is a good flow through the spill pipe. The pipe normally goes to the tank and yesterday I checked the flow rate at the pump when the engine was cold and after it had stopped, no change. I also ran the pump for 30 minutes just going straight from and to the tank with only the pre pump filter in use. Good flow all the time so not the pump faltering. I put grips on the hose to constrict it and give the pump some pressure to work against.
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