Night Hawk Posted December 16, 2012 Report Share Posted December 16, 2012 Hi there, I wonder if anyone's come across this before....or could suggest a way forward: Started up the engine this afternoon and, as usual, is burst into its enthusiastic chug after a few turns of the key. I should mention that we've not been to the boat for several weeks - busy at work. There was a new noise coming up from the depths - a slight metallic grating noise. I also noticed that the tachometer hadn't moved to it's usual tickover reading of 800rpm, it hadn't moved much from turning the engine on. I recall during the last summer something similar happened just the once, there was a grinding noise for a few moments with the tachometer not moving much...then within a few seconds, the grinding noise stopped and the tachometer shot to its usual position. Has anybody encountered this? Any suggestions would be gratefully received....I fully expect to have to arrange for an engineer to call. Regards, Andrew Andrew Link to comment Share on other sites More sharing options...
nicknorman Posted December 16, 2012 Report Share Posted December 16, 2012 (edited) Hi there, I wonder if anyone's come across this before....or could suggest a way forward: Started up the engine this afternoon and, as usual, is burst into its enthusiastic chug after a few turns of the key. I should mention that we've not been to the boat for several weeks - busy at work. There was a new noise coming up from the depths - a slight metallic grating noise. I also noticed that the tachometer hadn't moved to it's usual tickover reading of 800rpm, it hadn't moved much from turning the engine on. I recall during the last summer something similar happened just the once, there was a grinding noise for a few moments with the tachometer not moving much...then within a few seconds, the grinding noise stopped and the tachometer shot to its usual position. Has anybody encountered this? Any suggestions would be gratefully received....I fully expect to have to arrange for an engineer to call. Regards, Andrew The tacho not moving suggests the alternator is not being driven properly. Although the sound you describe doesn't sound like a slipping belt, that might be worth checking. If it really is a metallic sound, could the crankshaft pulley be loose? Obviously it then started driving correctly - this could be due to the belt heating up and becoming more sticky (if loose belt was the issue) or the crank pulley welding itself to the crankshaft. Edited December 16, 2012 by nicknorman Link to comment Share on other sites More sharing options...
bizzard Posted December 16, 2012 Report Share Posted December 16, 2012 Hi there, I wonder if anyone's come across this before....or could suggest a way forward: Started up the engine this afternoon and, as usual, is burst into its enthusiastic chug after a few turns of the key. I should mention that we've not been to the boat for several weeks - busy at work. There was a new noise coming up from the depths - a slight metallic grating noise. I also noticed that the tachometer hadn't moved to it's usual tickover reading of 800rpm, it hadn't moved much from turning the engine on. I recall during the last summer something similar happened just the once, there was a grinding noise for a few moments with the tachometer not moving much...then within a few seconds, the grinding noise stopped and the tachometer shot to its usual position. Has anybody encountered this? Any suggestions would be gratefully received....I fully expect to have to arrange for an engineer to call. Regards, Andrew Andrew If the rev counter takes its feed from the alternator (probably) it could be the alternator causing the noise and the failing rev counter, slip the drive belt off and run the engine and see if the noise disappears. Link to comment Share on other sites More sharing options...
Night Hawk Posted December 16, 2012 Author Report Share Posted December 16, 2012 I'll have a look next time we're up and check that the belts are tight enough.... Cheers for that. Link to comment Share on other sites More sharing options...
BEngo Posted December 17, 2012 Report Share Posted December 17, 2012 I'll have a look next time we're up and check that the belts are tight enough.... Cheers for that. Take the belts off and check that the alternator (and water pump if its driven by the same belt) is easily and smoothly turned by hand, too. N Link to comment Share on other sites More sharing options...
n.b.Goldie Posted December 17, 2012 Report Share Posted December 17, 2012 Had a similar problem on a car engine. Turned out to be the alternator bearings failing. Regards Ditchdabbler Link to comment Share on other sites More sharing options...
Night Hawk Posted January 1, 2013 Author Report Share Posted January 1, 2013 I'll have a look next time we're up and check that the belts are tight enough.... Cheers for that. Turned out to be a very loose belt. Thanks guys, you're the best. Link to comment Share on other sites More sharing options...
Night Hawk Posted April 1, 2013 Author Report Share Posted April 1, 2013 Ah....no it didn't....the noise is back, the rev counter isn't moving...and the 'voltmeter' that has been showing 14.4v for years is now showing 12v...and I'm sure the 'beep' the engine makes prior to starting up is tooting away as well. Awaiting the arrival of the engineer in the next day or two. Link to comment Share on other sites More sharing options...
n.b.Goldie Posted April 1, 2013 Report Share Posted April 1, 2013 Bet it is the alternator. Regards Ditchdabbler Link to comment Share on other sites More sharing options...
Slim Posted April 1, 2013 Report Share Posted April 1, 2013 Could it be a loose alternator pulley? Frank Link to comment Share on other sites More sharing options...
Tony Brooks Posted April 2, 2013 Report Share Posted April 2, 2013 Could it be a loose alternator pulley? Frank If its a pressed tin one half may have split and fallen off. Link to comment Share on other sites More sharing options...
Night Hawk Posted April 4, 2013 Author Report Share Posted April 4, 2013 Well the engineer has been out and has told me that the belts are loose. The bolt that holds the tension things has sheered off. The spacer had fallen off and the lower alternator belt wasn't doing much. The sheered bolt has to be extracted from the engine case and replaced....The only thing is it's well tricky to remove the sheered bolt....He'll have a jolly good go at it but might have to lift the engine to get at it. So there we go. We finally have a diagnosis. Now we await the bill Link to comment Share on other sites More sharing options...
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