Yesterday on our way out to our weekend races, My 1983 Yanmar 2GM dropped down from 3000 RPMs to 2000 without me adjusting the throttle, and began to produce lots of black smoke. We were almost out to the race course, so I hoisted sail, killed the engine and determined to investigate more when the races were over. Once races were completed (we got our second first place), I restarted the engine, and had good throttle control, and no smoke. Since it was again running correctly I headed back in and towards our dock. About an hour later as we neared our canal entrance off of the ICW the motor again dropped to 2200 RPM and started smoking. I lowered the throttle hoping to make it back to the dock, but it eventually stalled completely and wouldn't restart. I dropped anchor in the ICW and began to try to figure out what was wrong before I called TowBoat US. I have no fuel gauge, so one of the first things I checked was fuel level. We were out of diesel. I refilled with fresh diesel form the Jerry can I keep aboard, I re-primed, and she started right up and acted normal again all the way to our dock.
My question is, can a low fuel event cause black smoke? Could it be the dregs in the bottom of the tank causing some sort of clog that causes black smoke? The loss of power due to low fuel I can understand. It is the black smoke that has me puzzled.
I plan to replace both of the fuel filters before we go out again, and will let you know if they were dirty. They are only about a year old. There was no visible water in the Racor, but there was a very small amount of sediment in the bottom.
This is a raw water cooled 2GM 13hp. I had the short mixing elbow off two weeks ago while I installed a brand new fuel lift pump, and there was no appreciable carbon build up.
Any insights into this issue would be greatly appreciated.
My question is, can a low fuel event cause black smoke? Could it be the dregs in the bottom of the tank causing some sort of clog that causes black smoke? The loss of power due to low fuel I can understand. It is the black smoke that has me puzzled.
I plan to replace both of the fuel filters before we go out again, and will let you know if they were dirty. They are only about a year old. There was no visible water in the Racor, but there was a very small amount of sediment in the bottom.
This is a raw water cooled 2GM 13hp. I had the short mixing elbow off two weeks ago while I installed a brand new fuel lift pump, and there was no appreciable carbon build up.
Any insights into this issue would be greatly appreciated.