Sunday, May 31, 2009

A little delayed

Chris here... over the past few days we've been having some trouble starting our diesel engine. We'd push the start button and it would crank very slowly, and then after a few tries it would turn over. This morning, it wouldn't turn over. Not only that, but I held the start button in for a bit too long and smoke was coming off of the starter motor. I'm sure I burned something up there. We pulled out our Yanmar manuals, our Nigel Calder book and other references, and started working on diagnosing the engine. After staring at everything for a while, we called our good friend Gene, one of our dock neighbors on Lake Champlain, and also a mechanic. He asked us to check the voltage at the starter while cranking, so we pulled out our voltmeter, tried to figure out what to touch, and then cranked the engine. Three seconds later, it started. We know we have to, at a minimum, replace our starter motor now, but I'm not convinced that was the original issue.

Once the engine was started, an hour after our planned departure time, we looked at the weather. There's a huge storm moving in from the Florida coast and moving fast. At this point we're hanging tight until 9:30 or 10:00 so we can follow its progress and see if it will turn before reaching Nassau, like most of the other storms have, or if it will track right across our path. So - if you see SPOT updates, you'll know we have left. If you don't, we're staying put for another day or two.


Poppi said...

Poppi here: The starter motor smoking doesn't necessarily mean that it needs to be replaced...just that it got hot. But, it should not get hot. It gets hot because it was drawing too much current. This could be caused by: low voltage (a battery problem), excessive load (an engine problem). A diesel can crank hard due to: failure of the compression release system (if your engine has one), a bad bearing, or clutch/transmission not disengaged. The starter itself could have a problem, such as a bad bearing, bad brushes, or a corroded armature. One last possibility is a high-resistant (corroded) connection, either at the starter motor, battery supply, or ground (either at the battery or starter). The fact that it started after a while makes me think it most likely is a battery problem; either a weak battery or bad connection. Let me know how things progress. Love, Poppi, the old-sailor-man.

Poppi said...

Poppi here again: Oh! I forgot about the glow plugs. I believe your engine has glow plugs; resistant heaters in each cylinder which, when you turn the engine on, get hot, to help start the engine. If they aren't working, the engine won't start. I'm not sure how yours work, but some engines even sense to make sure they are on, and hot, before the engine cranks. Does your engine even crank? Or does it crank hard (ie. turns over, but slowly)? I think you said it does turn over, but slowly, so I don't think there is a problem with the glow plugs. If your batteries indicate a good charge, then the problem is either with the starter (bad starter bearing/brushes/connection/starter loose) or with the engine (bad bearing/compression release). Most likely it is a starter problem. Love, Poppi

Tom Ray said...

Your starter motor may be OK, and I disagree a bit with Poppi's comment above that it should not get hot. It will get hot if you crank too long, even if everything is in perfect condition. My general rule is, if you have to crank a diesel engine as long as 30 seconds, you should then let the starter rest and cool for a few minutes before cranking it again.