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Generator Question

Discussion in 'Generators' started by Kafue, Nov 5, 2012.

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  1. bohans

    bohans New Member

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    My Northern Lights genset once did the same thing. I could see airbubbles in the secondary filter pinned to the engine. The air leak was coming from the manual priming pump. No matter how hard you screwed it down, it would still find air. So i screwed it down with large pliers and then coated the entire seal in gasket glue. Since then no trouble at all. Not a single leak. I do not need the manual prime as the fule system has a priming pump on the manifold which i use to prime if ever necessary.

    Hope this helps.
  2. Kafue

    Kafue Senior Member

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    Latest

    Long day:
    The genset kept shutting down, even with new fuel line. I did believe it could be an air block but simplest thing was to take the new fuel feed line, at the same distance from the genset, disconnect from the fuel manifold on the port engine, then feed into a fresh 20 litre container of diesel straight from the local supplier.i.e CLEAN FUEL.
    I did this this a few hours ago, and so far the genset is running as smooth as silk. NO PROBLEMS at all. It has run problem free ever since I placed the feed line in the drum of fuel.
    I believe that the problem is bad fuel.
    The engines run because the strength of the 12v71n's fuel pump, sucking the fuel through the racors is sufficient, although many times I have had to use the extra prime pumps to get them rolling at cold start until the flow is sufficient. However, the genset which feeds from the same fuel manifold, does not have that suction power and starves unless I hit the prime pumps as I hear it stutter.
    They say half a problem is solved by finding the cause.
    Well, mine is old fibreglass tanks with a lot of crap in them feeding three motors, one of which is too weak to cope with the issue.
    What do you guys think is the best solution?
    In general I believe a Fuel tank clean and fuel polish.
    Short term: run the genset from a new temporary tank?
  3. captainviv

    captainviv Member

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    kafue , i once had similar problem on my genny. i tried to blow with my mouth on line , but , it was hard. i then used a compressor to blow it out . all was good then . either there was a blockage in the line or the tank pick up. you say you are using the port engine fuel supply line , maybe there is a blockage of some sorts in the "t" fitting you are using .
  4. K1W1

    K1W1 Senior Member

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    Hi,

    Do you have vacuum gauges on your Racors?

    If so what is the difference between clean filters and the time when problems arise.

    If the filters are getting blocked the vacuum between them and the engine will be a lot higher than normal and any leak no matter how small will let air in.

    DD's pump a huge amount of fuel compared to what they burn, the excess is used for cooling and lubrication of the Injectors.

    Cleaning the tanks and the fuel lines is the best way to get rid of most growth in your system.

    If you do not have much fuel in the tanks bite the bullet and dump it, when you refill either with your polished fuel or new dose it with an anti biocide.

    Capt J has one he swears by I haven't had the chance to use it yet but if it works well in So Fl it will also be ok in Queensland.

    If the one Capt J recommends isn't available, BP Australia seems to have one that will do the job http://www.bp.com/retail/liveassets...s/0_999/Fungal_Contamination_ADF_on_Boats.pdf
  5. dennismc

    dennismc Senior Member

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    I ended up installing a 30 gallon day tk to feed my gensets, the new sets just don't have the strong enough fuel pumps to lift when the main tks get low, no problems ever since, took quite a while to trace that as the old gens worked great .
  6. karo1776

    karo1776 Senior Member

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    K1W1
    Is correct... and proper in his answer... the pressure gages after the filters but before the fuel supply pump measure vacuum or pressure below atmosphere. I use the term "pressure" from absolute... .

    Also, ALL injector systems do flow more fuel than the injectors actually squirt in the combustion chambers, as K1W1 says as to DD. So if you are staving the engine for fuel it can lead to overheating of injectors and other components and premature wear. Leakage in the return lines just wastes fuel and creates a fuel leak hazard...

    One point I add is some diesel pumps (Bosch designs) have a manual or priming pump which the pump plunger is screwed into the injection pump when not being used (most of the time). If this becomes loose you have a major air leak into the fuel inlet supply side to the injection pump... as the supply pump supplies this you get a fuel leak. But importantly it allows the injection pump not to receive sufficient supply pressure. Just like any fitting leakage. If your pump has this feature FIRST CHECK THE PLUNGER IS SCREWED IN SNUG. It vibrates loose. AND check the seal on the plunger head where it screws down to seal.

    One point that I insist on on main engines and like on gen sets... this really is super overkill on small boats but over 50 feet offshore you should consider.
    Exhaust gas temperature sensors (thermocouples install near as possible to the exhaust valve on each cylinder)... usually these are installed in the exhaust manifold (not thru an area of cooling water jacket) at or near the gasket mounting flange. These temperatures sensors are either to a EGT gauge with a selectable per cylinder function; separate gauge for each sensor, or; a computer data system. WHY, is I can tell instantly any problem with the cylinder function... injector, valve lash, valve, fuel starvation etc. If done with a computer monitor and data history recorder... you (the engineer crew) can tell status and faults developing. In fact, the computer monitoring system should keep track of all the sensors in the propulsion and hotel load systems... and all the miso systems such as water purification, sewage, etc etc. On watch the crew can be trained to check these reports hourly and therefore find problems before you loose it.

    On owner operated boats this is a good idea but you have to learn enough to use this data.

    BUT AT SEA... do you really want to be mystified by some petty problem... and they tend to show up when you least want them... rough conditions... just before coming in to meet the wife for dinner and you are running late... etc etc etc.
    Without power you cannot run bilge pumps, out run storms, maneuver in heavy seas or be safe...
  7. Kafue

    Kafue Senior Member

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    Hi K1W1,
    There are pressure gauges on the racors, there is one gauge per side that runs up the pressure only when I engage the manual prime pumps. They cut out as soon as pressure has been reached. I have 3 racors per side only one in use at the moment so I will swap to a clean one and try the prime pump for the pressure.

    The main engines have until now shown only cold start problems (needing priming) but when up and running they run strong ....touch wood.

    My experiment yesterday with the fuel container went well. The genset ran smoothly until the fuel ran out (20 litres).

    re: dirty fuel. I completely agree with you. I will check today where there is a place to polish the fuel.
    I do not have accurate fuel gauges (not ONE site gauge on the boat!) just the mid tank has a float gauge, the rest use tank tender which is not operating accurately.
    So I keep a fuel log and I estimate I am carrying approximately 1700 litres which is $2,737. Rather not dump it yet.

    As for an anti-biocide, I reckon the one I just used “shook” things up **** good, so I might the same with the other tanks. $80 treats 1000 litres.

    So is that what cleaning out a tank entails? How do you get all the crap back out? Just run it through the lines?
  8. Kafue

    Kafue Senior Member

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    Many thanks for taking so much time to assist, I will get rid of the fuel and clean the tanks. Your advice is appreciated and taken.
  9. Kafue

    Kafue Senior Member

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    Exactly what I will need to do this trip and until I get the new fuel and takns cleaned.
  10. chesapeake46

    chesapeake46 Senior Member

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    Hi,
    were you able to confirm that you have limits like a low oil or high temp or no raw water flow ?
    if so can you jump them temporarily or keep a test light attached to them to confirm it is air in the system or rule out a cantankerous limit ?

    My Onan only has a low oil pressure limit.

    It also has a relay that engages, by way of the start switch, that by passes the low oil pressure switch allowing the genny to start. The low oil limit switch holds this reay in also.
    The relay keeps the fuel shut off solenoid from engaging and cutting fuel to the engine.

    The last time my genny had a stalling problem it was the relay acting up.
  11. Kafue

    Kafue Senior Member

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    Water flow seems good. I have new solenoid and fuel pump.
  12. karo1776

    karo1776 Senior Member

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    Polishing fuel...

    Kafue:
    It appears you have quite a bit of fuel that is contaminated. And, possibly the tanks are contaminated.
    Well this is a problem. You have to pay to have the fuel thrown out and it is expensive to replace.
    It seems the fuel when clean works fine... so it is not to the point other than crud in it of being deteriorated.

    What to do. Well on a bigger boat you likely have several tanks and a fuel transfer system with strainer filters. In that case you simply pump out one of the tanks into another(s) using the fuel transfer system... putting it through the filter system. Then clean the contaminated tank completely... sparkly clean. Dry it out. Re-transfer the fuel from one of the other tanks through the transfer system and filters to the now clean tank... using the cleanest of the tanks to draw from. Then take and make sure that tank is emptied and then clean it out sparkling clean... transfer the fuel through the transfer system and filters from the next cleanest tank into this clean tank... AND SO ON.

    But on smaller boats you may not have this in place. So you will have to jury rig something or install a transfer system with this kind of filter setup... Strainer > Water Separator filter > Rough filter around 20 microns > Fine filter of less than 5 microns (2 preferred). Use big filters of similar flow rating and a pump sized to flow the needed flow in the mid range of the recommended by the filter manufacturer. You can purchase such filter systems in numerous sizes... I suppose someone has a setup with the pump installed. This system can be separate and kept on shore or in a storage space on the boat... and bought out for occasional use. Or you can instal as a system in the boat. Sizing should be reasonable for the size tanks and quantity of fuel. But a temporary or emergency setup... can be very small and you will just have to put up with it taking hours to pump out a tank. On shore at dock you can leave it run while you do other things or errands. If the boat sets a lot then this operation (without the tank cleaning once you get them clean) can be done about once a month to max of once a quarter. You leave one tank low or empty when you come in to port... and that provides a place to dump the polished fuel.

    Even the smallest boat with multiple tanks can have this rigged up. Yes, on a big boat its built in from the builder... on a small you get to do it or hire someone. On a big boat the crew does it... on a small boat you is the crew!

    Warning if the fuel is fine but has algae in it... I would not use a algae killer... and simply get on tank empty and clean it... then use the process above. You will clean the algae and growth out when you clean the tank... stinking mess that is. That trapped in the strainer and filters of the transfer system... you will deal with as needed... other than the water separator (which you must keep clean and empty to work... does not work well full of water) I should note the dirtier the filters are, to the point of no flow, the cleaner they will filter the fuel... just take more time! A fuel transfer system is important even if very simple and crude... even handy on a 20 foot boat. You can in that case use portable tank for your clean tank!

    NOTE: IF you have installed a small day tank which allows a couple hours to maybe 8 hrs operations then the installed piping for the tanks in the boat can be adapted to the transfer system and simply isolate the engines from it all with the day or small tank. OR you can designate the smallest of the installed tanks into a day tank... and keep it clean and full of filtered full. Tanks empty (with some fuel remaining as dredges) or part full are more susceptible to condensation and growth of crude than full to brim tanks. With such a system the problems are in the transfer system not the supply to the engines... and you have a buffer for problems.
    Last edited: Nov 15, 2012
  13. Kafue

    Kafue Senior Member

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    Thanks Karo1776.
    I have installed a new 24volt fuel transfer pump which I use to transfer between tanks. This transfers via the Racors which are 30 microns. It does take a while to move the fuel between the tanks. So I have always considered this as “polishing” the fuel.
    Question is, beside using the fuel additive, how do I efficiently clean the tanks, I have 5 of them. 2 large, 1 medium, 2 small?
    Thanks again.
  14. Capt J

    Capt J Senior Member

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    You won't......You could put a 2 micron filter in the racor and transfer it between tanks. Polishing fuel is generally done to 10 microns, but you still have algae on the tank sides, and it seems to spread right back within a month or two after polishing.

    I have had really good luck with Power services clear tank diesel.....and spoke to them on the last boat (the 61' Viking SC I took the Milwaukee), they recommended using both the clear tank diesel, and the biokleen additive together, then after that tank just the biokleen. The owner did that and the algae is gone. We went through 12 (80%) tanks of fuel on the way up with no additives and I was changing fuel filters everyday at first to every other day even at the end of the 14 day trip.

    Honestly, it sounds like you're just pissing in the wind. How many Inches of vaccuum is on the fuel filter when the generator is running? Many Hatteras, the generator will only suck fuel out of 1 fuel tank regardless of where the main engine fuel valves are set. Are you sure you're is pulling off of the racor? I had an issue like yours and it turned out to be a bad diode. When it would get warm inside the sound shield after the generator was running for a few hours, then gen would just shut down......The fact that you have to run the priming pumps to start both motor also sounds like you have an air leak in your fuel lines somewhere. I'd put a piece of clear fuel hose, after the racor, and before the generator and see if it's drawing solid fuel. I would also make sure your fuel tank vents are clear. I've had diesels run on fuel that was 3-5 years old and algae ridden, and they never shut down as long as you kept changing the fuel filters when they clogged.......It can also be a bad shutdown sensor......When it shuts down, disconnect the oil pressure shutdown sensor, then the overheat sensor, etc etc......Also, have you verified operating temperature? It's quite possible your heat exchanger is blocked and causing it to run hot and shutdown.....

    If I remember correctly, the 53' Hatteras SF had the generator running off of 1 tank only, which was the one in the rear of the engine room.......
  15. karo1776

    karo1776 Senior Member

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    Capt J is right... what I was referring to is mechanically cleaning the tanks out. Just pumping fuel will not do it as he says. On smaller boats and some larger boats the tanks cannot be cleaned out mechanically without a yard doing it. I will later today explain how to flush tanks. But usually that is a professional deal but you can do it too.

    However, he is right too that you may have to simply chemically clean the tanks... as he describes. And, you will need the fine filters installed (5 Micron or less... 2 is good) to do it that way. And, you need to do it at the dock not at sea preferably. My fear is if you have dirty contaminated with growth full... and try it underway you may find yourself dead in the water. A larger boat with double bottom welded in tanks... the cleaning deal can be very challenging. Or, if a glass boat with built-in tankage. if you have plastic or stainless or galvanized installed tanks which are not part of the structure of the boat it is easier as you don't have so manny nooks and cranes.
  16. Liberty

    Liberty Senior Member

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    None of this sounds fun Kafue.

    You could always stick on a verrrry big solar panel on your roof and a verrrrrrrry, verrrrrrry big set of house batteries ...

    :D:D
  17. Kafue

    Kafue Senior Member

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    I think the generator runs from the tank selected by the port tank, hence the fuel feed line comes from the manifold fed from the port engine. This makes sense as it comes via the same racors as the P engine.
    I have found a guy with a good reputation who will give me a quote to clean the tanks. After that I will keep the fuel treated. I just hope I can get it done BEFORE I wanted to leave for holidays.
  18. Kafue

    Kafue Senior Member

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    Yeah thanks Mate!
    Lucky I started prep work this far ahead.
    Now ..... as of this afternoon, my youngest son has been selected to join his schools holiday rowing teams camp in Grafton, same bloody week as our holiday!
    Looks like I may go twice, once with my wife (actually sounds great!) then with my son and his mates.
  19. Kafue

    Kafue Senior Member

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    James I just ordered another 6 filters as the additive I used must be very effective, it has TOTALLY clogged up the one filter on the port engine and even the engine won't stay running unless I engage the second Racor. I think you suggested this as a cause in a previous post.
    Now what I will do is keep changing Racors until the tanks are professionally cleaned. The idea of using additive for temporary results and blocking filters continuosly makes no sense, except to get me over the Christmas break if I have to.
    Thanks and Cheers Mate.
  20. karo1776

    karo1776 Senior Member

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    Kafue... the correct "French" term is Putain de Merde... which roughly translates _ _ cking Hell.

    When I was young I got into enough of those... to know better now.

    Anyway, I started to write up up the process... but then realized that was a big enough hell that it would scare you off from the work. Yes, hire the specialist... who has a good reputation... you need the tanks cleaned!

    Mechanically doing it is basically washing out the tanks with a cleaner or fuel treated with a cleaner chemical mess... OR draining and crawling into the tanks and wiping them out. The mechanical/chemical cleaning rinse is either done with near empty tanks and a pressure spray OR with fuel tanks and high rate of circulation to scrub the crud off the sides... and a large rate of flush through big filters... I have seen also ultra sonic component used in the later fuel tank situation. To hire either are not cheap... but it is cheap for the work involved and the resultant lack of problems. In Navies its the crew... seldom yacht crews put up with such expectations... and you end up paying anyway... as you lose crew. On smaller self operated boats, where your time is free, its you. But professionals that are reputable and reliable are the usual route. Actually, if you are in an upscale marina... you get the boat to the repair yard in the commercial area and they do it there... DO NOT TRY the do it yourself route in Monte Carlo... or Cap d'Ail... or something, they don't understand why you would do something: if your neighbors see you are doing something like dirty work on the boat... better prepare for a visit and fine by some bureaucratic type task force... they will find you spilled a teaspoon somewhere or you did something else or your tax records are not up to snuff... the fuel records are where they start to unravel things and you think.... oh maybe I should have just bought a new boat and the VAT to pay... or the wife is right... about the whole boat deal... and even the row boat in the pond looks too much trouble when she asks; Quelle est la profondeur de l'eau dans l'étang? Which really means... it had better not be deeper than a wading pool.

    Keeping the tanks clean... well you can treat the fuel and keep the tanks absolutely FULL. Or drained absolutely dry and fill up when you go out. The later is not real practical as you tend to have to run with low fuel all the time and estimate how much you need... and at sea that is a safety issue.

    ALSO, keeping the tanks clean: if you have a transfer system with filters you can continually, as part of routine maintenance, polish the fuel by transferring through you on board system from one tank to the other. If you have a very small transfer system you might just leave it running all the time switching fuel around every time you go out... to keep the fuel crud free.
    Its sort of like infection and keeping it in control.

    If you use the boat regularly and rotate tanks so you use the oldest fuel first... that works. If the boat is not used much you need to do the transfer around system... to keep it clean. In Navies if the boat is not operated for long periods it is usually pumped into a barge and tanks kept dry... but I am sure you don't have one of those floating around.

    The problem with doing yourself is the spill regulations in all marinas now days... and dumping rules at sea. It used to be in the olden day of yore... you have bad fuel... when it was cheap... you simply dumped it at sea!