magpie patrick Posted October 4, 2007 Report Posted October 4, 2007 Recently I've noticed that Ripple is making a small amount of wash when in neutral: the propellor is obviously turning slighty. This only occurs on starting the engine when the boat hasn't been used for a few days. If we've been cruising the previous day it doesn't happen, and once we've got going it doesn't happen. Is this early warning of a problem? it didn't used to do it. BTW, I start with the single lever in the central position and the little switch "in gear" so the engine starts at low revs.
blackrose Posted October 4, 2007 Report Posted October 4, 2007 (edited) Recently I've noticed that Ripple is making a small amount of wash when in neutral: the propellor is obviously turning slighty. This only occurs on starting the engine when the boat hasn't been used for a few days. If we've been cruising the previous day it doesn't happen, and once we've got going it doesn't happen. Is this early warning of a problem? it didn't used to do it. BTW, I start with the single lever in the central position and the little switch "in gear" so the engine starts at low revs. I don't know much about gearboxes but I'd start by checking the oil level in the gearbox. If you can I'd change it at the same time. Do you know what gearbox it is? Edited October 4, 2007 by blackrose
bottle Posted October 4, 2007 Report Posted October 4, 2007 Hi My thoughts are the same as blackrose, time to change/check the oil. Your method of starting is not wrong, all the little 'in gear' switch does is connect the lever to the cables that operate the gearbox. If you put the 'in gear' switch in the 'out of gear' position it does not effect the gear box but just allows the engine to be 'revved' without the prop turning. Some engines will not start without the lever moved forward to the 'fast tickover' position that is why 'in/out' switch is there.
RobinJ Posted October 4, 2007 Report Posted October 4, 2007 BTW, I start with the single lever in the central position and the little switch "in gear" so the engine starts at low revs. Have you checked that you can set it to 'out of gear' as the adjustment may have slipped. It could be that every once in a while it remains in forward or reverse when the lever is vertical!
mayalld Posted October 4, 2007 Report Posted October 4, 2007 Recently I've noticed that Ripple is making a small amount of wash when in neutral: the propellor is obviously turning slighty. This only occurs on starting the engine when the boat hasn't been used for a few days. If we've been cruising the previous day it doesn't happen, and once we've got going it doesn't happen. Is this early warning of a problem? it didn't used to do it. BTW, I start with the single lever in the central position and the little switch "in gear" so the engine starts at low revs. Is this a Lister gearbox? If so, check that the oil level in the reversing box (closest to the engine) is correct. Lack of oil makes Lister boxes stick in forward. Note, however, that it is entirely normal for the prop to turn a few times on starting (until oil pressure is built up) on these boxes.
magpie patrick Posted October 4, 2007 Author Report Posted October 4, 2007 Thanks for that: I've got all next week on the boat and will check and get answers: not least about the type of gear box it is. The engine is a BMC 1.8 and starts very easily after about ten seconds of pre-heat. I can flip to "out of gear" and sometimes do if the cruise is going to start at tickover for a while (say, starting from the middle of a long line of boats) as the alternator only cuts in after the first time the engine is revved. There are a whole host of foibles to the set up that last until the engine is warmed up but this is a new one. I'll be online whilst on board so will check and update this thread.
chris w Posted October 4, 2007 Report Posted October 4, 2007 ............................as the alternator only cuts in after the first time the engine is revved. Check that there is a resistor in parallel with the alternator charging light (on the control panel). It should be about 47 ohms approx. The reason the alternator is not cutting in immediately is because there is not enough "excitation" current through the rotor when you turn on the ignition. The ignition lamp alone rarely provides a low enough resistance path and so a resistor is added in parallel. Chris
magpie patrick Posted October 18, 2007 Author Report Posted October 18, 2007 OK folks: It's a PRM 160 connected to a BMC 1.8. Oil level not a problem but has now been changed. Also developed a slightly alarming fault in that occasionally failed to engage gears when I put the revs on and then suddenly did engage with revs significant. Did this twice (both times at a cold start) after which I resolved to have the deckboars up when engaging gear for the first time of the day: needless to say it then didn't happen! I was hoping to see whether the control was working or not: that is, was the sticking in the cable or within the gear box On the alternator point: haven't checked but it's always been like this: since fitting a new alternator in May it only takes a blip on the revs and charging starts, the old one needed full revs on a warm engine which I should have seen as a warning sign that it was failing. That said, on this trip the alternator was struggling to deliver 14 volts (assuming dashboard dial is accurate) and the low voltage cut out on the fridge cut out each night suggesting low charge: this pervaded until Saturday when 14 volts was achieved after an hour or so and that night all the lights were much brighter!
John Orentas Posted October 18, 2007 Report Posted October 18, 2007 If the 'driving in neutral' thing is very minor, the propshaft simply creeping around, there is probably nothing wrong at all.. Many types of gearboxes will do this, even on motorcycles, it is a hydraulic effect, movement of oil transferring rotation from one gear to another.
magpie patrick Posted October 18, 2007 Author Report Posted October 18, 2007 Thanks John: it's slightly more than creeping but after a week examining it carefully I've concluded the same thing. I tend to look for early warnings of things going wrong and nip them in the bud and that's why I wanted to check this one out. Haven't worked out those two failures to engage gear: the effect was reminscent of the old fashioned double level control with engaging gear AFTER putting the revs on! But the gearbox point blank refuses to repeat the trick! Will keep an eye on it when we go up to Bugsworth in a few weeks time.
RobinJ Posted October 18, 2007 Report Posted October 18, 2007 OK folks: It's a PRM 160 connected to a BMC 1.8. Oil level not a problem but has now been changed. Also developed a slightly alarming fault in that occasionally failed to engage gears when I put the revs on and then suddenly did engage with revs significant. I was going to say it will be a PRM or Hurth - too late! When cold you can get some slow rotation until the oil 'warms' up, should be the same direction as the engine! If your not loosing oil and its at the right level (causes pump delay) then it will either be the friction surfaces wearing or a problem with the linkage. On the alternator point: haven't checked but it's always been like this: since fitting a new alternator in May it only takes a blip on the revs and charging starts, the old one needed full revs on a warm engine which I should have seen as a warning sign that it was failing. That said, on this trip the alternator was struggling to deliver 14 volts (assuming dashboard dial is accurate) and the low voltage cut out on the fridge cut out each night suggesting low charge: this pervaded until Saturday when 14 volts was achieved after an hour or so and that night all the lights were much brighter! It would appear that the batteries were pretty flat? If this continues after the batteries have recovered, check for sound connections and that the capacity of the wires are big enough.
Serendipity Posted October 18, 2007 Report Posted October 18, 2007 Thanks John: it's slightly more than creeping but after a week examining it carefully I've concluded the same thing. My PRM does this, about two revolutions per sec, hot or cold, and it takes a pole pulled hard against the propshaft to stop it turning if that's any consolation. Oil changed a year ago and levels are fine, and so I've just assumed it's caused by the effect John described and not worried about it.
David Schweizer Posted October 18, 2007 Report Posted October 18, 2007 If you are at all concerned, phone Newage Technical Department, they are very helpful,
chris w Posted October 18, 2007 Report Posted October 18, 2007 On the alternator point: haven't checked but it's always been like this: since fitting a new alternator in May it only takes a blip on the revs and charging starts, the old one needed full revs on a warm engine which I should have seen as a warning sign that it was failing. That said, on this trip the alternator was struggling to deliver 14 volts (assuming dashboard dial is accurate) and the low voltage cut out on the fridge cut out each night suggesting low charge: this pervaded until Saturday when 14 volts was achieved after an hour or so and that night all the lights were much brighter! Firstly, an alternator shouldn't need you to rev up to make the ignition light extinquish and for the alternator to start charging the batteries. A friend of mine had the same symptom on a second-hand boat he had bought and was told, by a "marine engineer" in a nearby boatyard, that he needed a new alternator. I told him that was nonsense, fitted a 47 ohm resistor across the ignition lamp, and the lamp now extinquishes immediately the engine starts - as it should. Re the charging voltage, check the voltage with a multimeter as the dashboard dial may be innacurately set (there will be a trimmer on it somewhere). My (new) control console dial was 0.5v out but is now reading accurately after readjustment. If the voltage is below 14v the alternator's regulator is either not suitable for charging boat batteries or is faulty and needs replacing. If the regulator has gone, you do not need to buy a new alternator. You can get the regulators for about a tenner from Ebay or ask Snibble, on this forum, as he's the alternator expert. Chris
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