Yanmar engine issues

[NoQuarter79]

I have an older yanmar 2gm20 with low engine hours that's always run great. Recently we were preparing to move the boat out of the way of a hurricane. We began our 45 mile trip only to have the engine fail within the first 30 minutes. The engine began to sputter, lose rpm, and eventually die. It immediately seemed as though it wasn't getting fuel. Sailed back to our start point and started working on it. So we know the lift pump is functioning properly. It seems to take a much longer time to bleed our system at the secondary fuel filter now, a friend mentioned that fuel getting to the injectors seemed a little weak. Now were going to look for blockage in our lines before the lift pump as well as the fuel line pick up and dip tube, we'll check if our lift pump has a screen that could have blockage. We changed our primary fuel filter and purged the system of old fuel. Could there be something I'm over looking? If water got into the fuel what could that mean for the engine in this situation?

[Teknishn]

Had the same thing happen to me recently with my 1GM. The GM series of engines are similar enough that I feel that I can comment on this. Had been motoring for about an hour when the engine sputtered and died with the same symptoms which you described. Went below and found my fuel/water seperator was filled with a fuel/water mixture. (I would hope that you also have a fuel/water seperator as well...if not, get one!). I had recently replaced my lift pump so I knew that was good. Had to remove and flush my fuel tank, replace ALL filters, disassemble and clean the High-pressure feed pump (Had been recently overhauled) and eventually had to replace the single injector on the 1GM. After bleeding the system the engine started and ran but had a knock-knock sound to it. Pulled the head and piston and found that the Conn rod bearing was bad. Water in fuel is NOT GOOD!

With that being said, the amount of water in the fuel, if that was the fault, that could have been injected into the engine before it died would have been minimal (just enough to prevent fuel combustion) and any damage to the engine itself MAY have been negligible, or MAYBE NOT.

[NoQuarter79]

When I removed the fuel line from the tank to the primary filter it was empty of fuel, I expected this to be full of diesel. I do not have a fuel water separator, but wouldn't my primary filter have had some water in the bottom if water was the culprit?

[NoQuarter79]

I apologize, I do have a water separator, but it looks clear of any fuel/ water separation.

[Lepke]

If you don't have water in the fuel and the fuel line is empty, you are most likely sucking air. It could be a plug if you have a strainer on the fuel pickup. Air is more common.

[NoQuarter79]

We detached the hose coming from the secondary filter going into the injector pump and attached a hose going straight into a Jerry can and still nothing. Can we deduct that its an issue ahead ofthe secondary filter? Some friends gave it all a good look previously before the hurricane and deduced it to be the injector pump, and were really just trying to find the problem elsewhere.

[Compass790]

I'm a bit uncertain of your explanation of a hose going to injector pump from jerrycan. Is it a gravity feed or are you expecting the injector pump to suck from the jerrycan? You need to feed the injector pump with a little bit of pressure. If you have the bottom of the jerrycan a foot or so higher than the injection pump & the feed hose siphoning out of jerrycan ( i.e. flowing already ) that should be ok.
Make sure you use filtered fuel for that as feeding your injection pump with unfiltered fuel could cause you grief. You should see all the crap we catch in our filter funnel when filling the tank. If you have no fuel in your line from the tank to the filter I'd solve that first if I understand your description properly. Your engine problem sounds like a fuel or air problem but you have to have fuel flowing from tank to filter before you attack the injection pump. Leave the injection pump till last as that is the least common problem. Lift pump, filters, tank suction line blockage & air leaks are much more likely than injection pump failure IMO. Start with the simple cheaper stuff first. Let us know how you get on. Good luck

[odonnellryan]

White smoke? Had a good amount of white smoke when I had a loose hose clamp on my fuel line that was letting air in near a priming bulb.