Fuel Vent Line & Other Tips Needed

[never monday]

JR,
The real problem with your overflow is the vent outlet is probably about 4" lower than your fill. When you fill the tank "to the neck" gravity is going to push the fuel out of the unrestricted vent because it's lower. Going to a larger vent will only exacerbate (big word) the problem.
And no there is no way to add a restriction.

Pat

[halyardz]

Again, thanks so much. Pat...don't know about the height of vent outlet in relation to the fill. I'll check today. No nobody has adjusted anything on that engine in at least 6 years. I doubt very much if the PO (I bought it late in 2001) had anything other than regular filter changes done. So no the valves haven't been adjusted, the injectors haven't been pulled etc. etc.

I'll try a number of the suggestions but I mut admit, I'm frustrated as in my area there are some mechanics that work ON small diesels but can't seem to find a specialist. Gas engines, no problem. If I were near the coast, there are a number of gents.
I'm literally up the river (Hudson). But I shouldn't bother you with my locatoin frustration. Jim

Marine mechanics ar hard to find. We have only two in this immediate area, and one has caused the sinking of 2 boats in the past 10 years. The other is so busy he will not even take on new work unless it is something he WANTS to do. I was the 3rd, but the owner of the shop I worked out of snorted all the profits, then drank the deposits, and the rest is history.
I found, even with my considerable mechanical skills, that I would often run into hidden issues when working on boats in the water, that would not be encountered working on the hard, or on other types of engines. The liablility made it impracticle to start my own shop after the crook went out of business. If you have a boat yard or chandlery in your area, I would start there in your search. The nice thing about the boating community is that word travels fast. If a guy has caused problems, you will hear about it. Unfortunately, the good mechanics are so over booked, it is hard to get them to work for you.
Fortunately, the work you need is fairly basic, and hard to screw up. If you have the time, you might take the money needed for the work, and invest it in a diesel course. A lot of vocational schools have decent courses that are not too pricy.
All I can say is good luck, and watch who you let work on your engine. Poor quality if far more costly at sea, than it is on the road.

[Alan Wheeler]

:Caused the Sinking of Two boats" MATE!!!! What can I say??

" I have good new's and bad new's. The good news is the engine is now fully rebuilt and has never ever run sweeter. The bad news.....umm, how can I put this......by the way, here's the bill, you can see I have given a small discount.....Oh and the boats being fully washed for you right now as we speak No sorry I don't take cheques, cash or Efftpos will be fine, and if ya need me, I will be out of town for a while. Got to go, the cars running.

[Richhh]

The CG specs are a bit behind the times with respect to fuel hoses. I'd use nothing but armored EPDM (ethylenePropyleneDiamineMonomer) hosing as its more compatible vs. diesel fuel. The usage of Copper in the fuel lines promotes fuel degradation. I prefer stainless steel with at least two 'stress relief' joints to prevent embrittlement due to vibration, etc. In ANY piping system choose double flared connections if possible. The simple and typically found 'compression fitting' should be considered SINGLE USE only and should be replaced (and the tubing 'trimed back' to undeformed metal) after you re-open them. Compression fittings deform the copper tube to make a seal and are a notorious site for air leakage.

To prevent 'foam-out' when filling the tank, consider to relocate the inlet fill hose so that it discharges onto the inside SIDE wall of the tank - not the middle. Also KNOW how much fuel you need to put into the tank and watch the delivery meter. A bubble trap can be arranged to break foam-out bubbles .... simply filling a section of the vent line with small bundle of 'capillary' tubes - the small tubes burst the bubbles but permit gas flow.

As regards the 250 rpm difference that you see, consider that most gages on boats are not calibrated and simply the difference you observe may be only a 'gage' fault. However and in addition to the other suggestions of injector, governor and high pressure pump overhaul, also consider that if you've been using degraded and contaminated fuel that there is a possibility that the exhaust system may be loaded with soot and that there is high exhaust manifold back pressure due to the carbon fouling --- may reduce output rpm - and you may not necessiarily see any smoke, etc. issuing out the end of the exhaust stack (this is called 'coking'). A similar exhaust blockage condition can be encountered at the area of the water injection elbow; as where the cooling water is injected to the exhaust, the sudden high temperatures encountered by the cooling water may cause calcium carbonate (rocks!) formation accumulation which also partly blocks the exhaust circuit and causes back pressure to the cylinders - hence power loss. Carbonate (precipitation) build-up is easily remedied by 'pickeling' the raw water circuit with an acid or (better) organic boiler descaling compound - usually performed as routine mainentance, especially when and in addition to cleaning out the heat exchanger. I wouldnt disassemble an exhaust system to simply look for blockage; but, if and when you replace the exhaust system next time consider to add a gage port so that you can monitor the exhaust pressure .... just a simple 'boss' to which you can add a gage when needed to check - the gage only installed when checking, otherwise removed.

For any engine, its best to establish a 'base-line' of operating data so that you have something to compare later on when you perceive something is failing.
At a 'designated' or specific rpm:
Gallons per minute of output cooling water (stopwatch and bucket at exhaust outlet).
Temperatures of inlet and outlet sides of heat exchanger .... you're establishing 'terminal differences'.
Exhaust manifold pressure.
Exhaust cooling raw water pressure (before injection elbow) - shows impeller 'slip' and also if water injection elbow is fouled.
Vacuum gages on fuel delivery system to monitor filter operation.

For tank diptubes, most keep the diptube off the bottom to prevent suction of accumulated water and large debris. An alternative to be sure that there is no water in the tank bottom (to prevent bacterial and fungal growth) simply run the dip tube all the way to bottom and place an EMPTY filter housing in the FIRST postion after the tank in the fuel delivery line. The water will separate by gravity from the oil in the empty filter housing ... simply and routinely drain off the water from the bottom of the 'empty' housing with a 'cock-valve' at the bottom of the housing occasionally to prevent the water from challenging the filters, and travelling further down stream. There is no way to easily drain water from bottom of a marine fuel tank, its easy to drain such a 'water-knock-out' pot.
If your normal source of fuel is unreliable and occasionally also delivers water (either emulsified or free water), consider to purchase a large fuel filter that has an added water absorbing starch (HydroxyMethylCellulose) - be sure to routinely monitor such a filter with a gage so that you can see when to change-out.

I can email you a schematic of fairly 'upgraded' fuel delivery system (110 gal.) that I have on my boat that also includes an onboard recirculation polishing system and a lock-in/lock-out gravity feed day tank to ensure an extremely reliable source of available fuel for 'emergencies'. Most boat fuel systems are quite 'primitive' and what I have would probably be considered 'state of the art'. email me @ RhmpL33ATattDOTnet if you want to view a 'serious' fuel system.

Hope this helps.

[never monday]

Richhh,
Great write up. I have to call your point on the EDPM. EDPM is not mentioned in the A.B.Y.C. Standards. This could be a point of contention with a surveyer or insurance company in the future. The Standards do spec certain types for hoses with SAE or UL ratings for certin applications. Noteably a rating of A1 for inboard applications.

[Richhh]

Pat -
Thanks for the kind words.

Just like any governmental regulation .... it takes a long time to change these 'specs'. The specified Buna & Neoprene compounds although still OK have been replaced with EPDM/EPR in industry about 15 years ago. Surveyors wouldnt have any reason to know such things until actually issued by the gov. agencies. as they are looking for the 'status-quo' and not the state-of-the-art, etc.

[GordMay]

RichH:
Great posts !!!
Tried emailing you, but mine got returned ...
"The following addresses had permanent fatal errors -----<RhmpL@att.net>(reason: 551 not our customer)"
Please forward your Fuel Schematic to:
<<<Gord@BoatPro.zzn.com>>>
Or, if a large file, to:
<<<engineering@cuthbertson.com>>>
Tks,
Gord

[Richhh]

Gord -
Sorry but my 'edit' of the post didnt go through...
My email: RhmpL33ATattDOTnet