Two weeks ago we installed a new starter/solenoid on our '77 Hunter 27. The engine is a single cylinder Yanmar SB8. The new starter cranked wonderfully, but the engine didn't want to start. We cranked and cranked and then finally, the engine began to run... BUT, the exhaust was coming out of the intake, not the exhaust pipe!!! The engine cover was off at the time and all we could do was stare at the smoke coming out of the engine for about 10 seconds before we gathered our wits enough to turn the fool thing off. It took about 5 minutes to gather our courage enough to try starting it again. We did, though, and after cranking for about 5 seconds it started right up... running correctly. We've since started it and stopped it a number of times, and haven't had any more problems. Question 1: How can this even happen? Question 2: Is it likely to happen again? Is there a way to prevent it? Question 3: Did we damage anything during that 10 seconds when the intake
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Wow!
Doug: I don't think that this could ever happen with a gas engine. With a diesel there is nothing electrical to keep the engine running. They run off of compression. There is a condition where the engine can actually "run away" with the fuel/throttle control in the stop condition and the engine will continue to run and even over-rev. The engine can run on diesel fuel and engine oil. The fuel shut-off will not even stop the engine under this condition. You would need to put a rag on the engine air intake to cut off the fuel supply. I doubt that it hurt anything. Do not think anyone can tell you it WON'T happen again. I would contact a Yanmar service center and ask them what really caused this to happen.
Doug: I don't think that this could ever happen with a gas engine. With a diesel there is nothing electrical to keep the engine running. They run off of compression. There is a condition where the engine can actually "run away" with the fuel/throttle control in the stop condition and the engine will continue to run and even over-rev. The engine can run on diesel fuel and engine oil. The fuel shut-off will not even stop the engine under this condition. You would need to put a rag on the engine air intake to cut off the fuel supply. I doubt that it hurt anything. Do not think anyone can tell you it WON'T happen again. I would contact a Yanmar service center and ask them what really caused this to happen.
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john renfro
putt-putt
hello doug, i don't know anything about yanmar but you can make two cycle motorcycles run backwards. to help prevent kicking back and running bacwards, keep your battery charged and your injection pump in correct time. john
hello doug, i don't know anything about yanmar but you can make two cycle motorcycles run backwards. to help prevent kicking back and running bacwards, keep your battery charged and your injection pump in correct time. john
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Kevin L. Woody
Crank crank crank...
Dear Doug, Thanks for the note. What has most likely happened to you and your YSB8, is that when you were cranking, cranking, cranking, cranking,… you produced soot/carbon in the cylinders. This soot most likely caused the value to not seat 100% causing the exhaust to exit the intake. My guess is that you will not have the problem reoccur again unless you crank, crank, crank, crank. If damage occurred you would have not been able to get motor to run again. You have also sucked up some seawater, which could have contributed to the smoke. If its not happening any longer, I would guess you have not destroyed the head gasket. Hope this helps. Kevin
Dear Doug, Thanks for the note. What has most likely happened to you and your YSB8, is that when you were cranking, cranking, cranking, cranking,… you produced soot/carbon in the cylinders. This soot most likely caused the value to not seat 100% causing the exhaust to exit the intake. My guess is that you will not have the problem reoccur again unless you crank, crank, crank, crank. If damage occurred you would have not been able to get motor to run again. You have also sucked up some seawater, which could have contributed to the smoke. If its not happening any longer, I would guess you have not destroyed the head gasket. Hope this helps. Kevin
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Doug T.
Thanks
Thanks Kevin -- that makes some sense. I don't think I sucked up any seawater, though -- my exhaust outlet was above the water line the whole time, so it shouldn't've pulled in any water. I'll be sure to watch out for that if I'm having trouble starting while the waves are washing over the exhaust outlet.
Thanks Kevin -- that makes some sense. I don't think I sucked up any seawater, though -- my exhaust outlet was above the water line the whole time, so it shouldn't've pulled in any water. I'll be sure to watch out for that if I'm having trouble starting while the waves are washing over the exhaust outlet.
Just a note!
Doug: What Kevin may be referring to is the fact that it has nothing to do with the exhaust outlet pulling in seawater. The fact that you were cranking your engine for a prolonged period of time allowed the seawater pump to pull seawater in thru the engine but there was NO exhaust to push it out of the muffler. Technically speaking you SHOULD turn off the raw water intake when you are starting your engine. Once it start, you should then open the raw water intake. If you engine is running OKAY now, I really would not worry about it. If you ever have a starting problem again, be sure to turn off the raw water intake while cranking.
Doug: What Kevin may be referring to is the fact that it has nothing to do with the exhaust outlet pulling in seawater. The fact that you were cranking your engine for a prolonged period of time allowed the seawater pump to pull seawater in thru the engine but there was NO exhaust to push it out of the muffler. Technically speaking you SHOULD turn off the raw water intake when you are starting your engine. Once it start, you should then open the raw water intake. If you engine is running OKAY now, I really would not worry about it. If you ever have a starting problem again, be sure to turn off the raw water intake while cranking.
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