Well, larry demers thought that I should post this for everyone on the board. We had been problem solving over the ethers about my cd30 cutter. a little history here, over this winter I changed fuel filters and upgraded electronics and installed a balmer 75amp.dual output alternator with balmars max-charge along with a link 10 battery monitor. the problems that arose took me beyond my level of incompetance. So here is my email to larry just recently.
Larry, I corresponded with yuou a month or two ago regarding fuel problems onboard milagro my 82 cd30 cutter with the volvo md7a engine.
well it looks as though the problems have been solved. what a task!
1. the fuel system, after sheared bleed screws on the injector pump and sheared banjo bolt on fuel return and the problems those brought were fixed, bleeding procedures followed the problem of restarting engine still was happening. ( engine would start but not restart) that brought about the following head scratchs and steps. the first was to disconnect the fuel lines from tank to racor, with inline shutoff in between. just 3-4ft of line, on this section I plugged and clamped one end, on the other I inserted fitting and vacuum gauge, took vacuum up to 60lbs. or so and watched the needle on the gauge...sure enough it dropped several pounds within minutes showing a leak somewhere allowing air into system. I then replaced fuel line and reset all fittings with tefflon tape snugged them down,, that section held pressure.( here is something else, old fuel line rose above tank then dropped down to fitting creating a vented loop of sorts a place for air to rise to and hard to bleed out) new line immediately drops to racor.
I then tested racor and short line to transfer pump. plugged inlet to racor, vacuum gauge inserted to fuel line to pump. this section held like a rock.
well by now I was feeling a little cocky after all this intrique and this has got to be the problem solved. bled the system once more. engine started almost before I turned the key, ran great then died. turned key, engine starts then dies. this went from head scratchs to pulling hair.
So I bypassed the fuel delivery system entirely. got can of diesel dropped fuel line into it, connected line to fuel pump bled system cranked engine...started and died. repeated several times so as to penetrate thickening skull of previously cocky captain.
at this point I saw two possibilities, sell boat and walk or get the less expensive of two culprits, transfer pump or injector pump. I bought the fuel pump reinstalled it , bled system ( Im getting really good at this by now)glanced nervously over shoulder to see if Poseidon was really there or what.
now the engine starts right up , runs fine.. I kill it, wait a few seconds, turn key it fires right up runs for 45 seconds then falters, repeat this several more times. runs and dies after 45 seconds.
heres what happened: going back to all the new electronics installed increased amp. load a lot, thats why I pulled old 35amp. alternator and replaced with 75 amp. and max charge regulator. to keep the two new group 30s up and the start battery. the max charge kicks in after 45 seconds.. to allow engine cranking without its load(alternator) drawing down batterys. just when engine faltered after 45 seconds at low rpms. at this point I dissconnected alternator and the engine runs great.
the alternator came with a 2.5"dia. pulley. now the 75 amp. is a 3horse model.. with that little pulley it was just too much for the volvo. I have since pulled it and replaced with a 4"dia. pulley which changed the ratio/load dramatically and still charges batterys in a resonable length of time.
what i found was air leaks in lines, faulty fuel pump and a alternator pulley to small for engine. what I won't do again is a lot of upgrades all at once to complicate and muddy the waters of problem solving if a problem rears its head.
recall a quote from latitudes and attitudes don't know who said it but its.... if its not broken..
fix it until it is.. hope this will help any of you out there if you run into weird stuff. best regards ben
btlandscapers@imagina.com
fuel and amp. load saga for milagro
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