Hello alll Following a bottom job, I could get full 3400 rpm and 7knots from the 16HP Yanmar on my 29.5 Hunter. Hurrah!!!! Today, after being faultless this morning,I had been running most of the way back to the marina at around 5kn and 2400 rpm but wanted to make the Bascule bridge opening. I pushed the revs up to 300rpm, (couldn't get anymore into 15kn headwind) And then it happened : light and buzzer....coolant temp, charging and oil pressure lights lit. Never happened before. I shut down and anchored up, checked the raw water strainer and impeller, changing the latter as I had planned to do so soon anyway even though the old one seemed okay if a little permanently radiused on the blades, let it cool for a while and then restarted and limped to the marina, during which time She seemed to be lacking in power and would give me 4kn at 2000 / 2200 rpm which seemed to be labouring. I know we were onto a breeze, but in the morning, she was doing around 5 knots at the same rpm. At the marina, I plugged in the shore power and when I lifted the lazarrette lid, the battery that I had used to start and run the house requirements was hot and there is an acid smell to it. The other house battery is cold. I religiously check the oil and coolant and transmission level before each days run, which gave me no concern this morning. Could it be that the voltage regulator is faulty and threfore the alternator charging caused both the battery to get hot and the engine to overheat? Frustradedly yours, Neil
2GM20F Overheating Problem
- Thread starter Neil Hodgson
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Electrical problem
Neil, you indications, hot battery and multiple alarm, would lead me to believe that you had an electrical short somewhere. Unfortunately, electrical problems are very difficult to find until they repeat themselves. Good luck.
Neil, you indications, hot battery and multiple alarm, would lead me to believe that you had an electrical short somewhere. Unfortunately, electrical problems are very difficult to find until they repeat themselves. Good luck.
The control panel
on my Yanmar 2GM has a three position switch. That switch, when in the middle position is the panel on without the lighted feature, the down position turns on the lights and the upper position tests the warning system. If you are running and switch to the up position all the lights and buzzers come on. If you have this toggle switch, you may have switched it momentarily to the upper postion. It has happened to me before. Your assumption that the voltage regulator may have malfunctioned and caused the engine to overheat doesn't make sense IMHO because that alternator would not be working that hard as to overheat the engine and if the pull were that great one would think that the belt would be in such a strain that it would malfunction. The engine HP is great enough to overcome an alternator that has locked up. I agree with BillR on the battery temp thoughts.
on my Yanmar 2GM has a three position switch. That switch, when in the middle position is the panel on without the lighted feature, the down position turns on the lights and the upper position tests the warning system. If you are running and switch to the up position all the lights and buzzers come on. If you have this toggle switch, you may have switched it momentarily to the upper postion. It has happened to me before. Your assumption that the voltage regulator may have malfunctioned and caused the engine to overheat doesn't make sense IMHO because that alternator would not be working that hard as to overheat the engine and if the pull were that great one would think that the belt would be in such a strain that it would malfunction. The engine HP is great enough to overcome an alternator that has locked up. I agree with BillR on the battery temp thoughts.
Transmission???
OK given all the below, if the engine is operating OK then there is something "sucking" the HP. The only thing that could do that is the tranny or prop. Check the fluid in the transmission. After motoring around for a while check the temp of the transmission. Could also be that you picked up something on the propshaft! You could try putting the transmission in neutral and hand spinning the propshaft. If it is hard to turn then a trip down to the prop would be in order. All three light will be on if you overheated the engine and then tried to restart. Since the engine is not turning, not alternator and you get a charge warning. Same idea for no oil pressure. These should go out shortly after the engine starts even with an overheated condition. So the buzzer sounds but only the hot light says lit after startup.
OK given all the below, if the engine is operating OK then there is something "sucking" the HP. The only thing that could do that is the tranny or prop. Check the fluid in the transmission. After motoring around for a while check the temp of the transmission. Could also be that you picked up something on the propshaft! You could try putting the transmission in neutral and hand spinning the propshaft. If it is hard to turn then a trip down to the prop would be in order. All three light will be on if you overheated the engine and then tried to restart. Since the engine is not turning, not alternator and you get a charge warning. Same idea for no oil pressure. These should go out shortly after the engine starts even with an overheated condition. So the buzzer sounds but only the hot light says lit after startup.
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