I rebuilt the Yanmar on my boat about 3 years ago. While it only has about 50 hours on it since, it has never failed me... until now. I was out this evening and returning to my dock when it started to "wind-down" a bit. I had installed a 12v priming pump during the rebuild and hit the switch for it just before it died. It seemed to help briefly...just enough to get me in the basin, but then quit. I landed at a t-head and did some troubleshooting:
1. I don't think the added pressure from the 12v pump really does anything. It would start and labor for a bit then die with the pump on or off.
2. The diesel in the tank is only a year old and I kept the tank almost topped-off all winter. The vent seems clear and there doesn't appear to be any water in the Racor bulb. The air intake muffler is also clear.
3. I finally got it idling and motored to my slip. After tying-up, I ran it under load pretty hard for a few minutes (or as hard as the noisy beast could go with no dark exhaust water coming out--I don't have a tach.) It will start to wind-down after a few minutes (not "miss", just slow down as if I moved the throttle) and head toward a stall, but I can keep it from stalling by going to lower rpm's.
Unless there are other suggestions, I will probably start with priming to check all of the banjo fittings for leakage and maybe draining the fuel in the lines, but it seems to be either rpm or temperature related. Hoping to make a run from Norfolk to New Bern later this summer...I need this engine to make it! Thanks in advance for any advice or considerations!
1. I don't think the added pressure from the 12v pump really does anything. It would start and labor for a bit then die with the pump on or off.
2. The diesel in the tank is only a year old and I kept the tank almost topped-off all winter. The vent seems clear and there doesn't appear to be any water in the Racor bulb. The air intake muffler is also clear.
3. I finally got it idling and motored to my slip. After tying-up, I ran it under load pretty hard for a few minutes (or as hard as the noisy beast could go with no dark exhaust water coming out--I don't have a tach.) It will start to wind-down after a few minutes (not "miss", just slow down as if I moved the throttle) and head toward a stall, but I can keep it from stalling by going to lower rpm's.
Unless there are other suggestions, I will probably start with priming to check all of the banjo fittings for leakage and maybe draining the fuel in the lines, but it seems to be either rpm or temperature related. Hoping to make a run from Norfolk to New Bern later this summer...I need this engine to make it! Thanks in advance for any advice or considerations!
