Yanmar stalling issue

[Gary J]

I've got an 04 28 TE with 315 Yanmar. About six months ago I started experiencing engine stalling when on plane, but only on occasion. It's becoming more frequent. It's as if the fuel supply is suddenly shut off. Sometimes it will restart, sometimes not. When the engine is running it runs perfectly. No smoke, no roughness. I've owned it since new and it is well maintained. I've gone through all the usual suspects. Filters are clean. (Wasted alot of money on filter replacements when they looked clean.) Checked all lines for any potential for air gaps. Pulled the fuel intake tube out of the tank and removed the screen. Tube looks good. Pumped the fuel tank twice. First time they found some algae, second time it was clean. The fuel is filtered and then pumped back into the tank. Most recently a mechanic pulled the fuel injection pump and sent it off to a shop. Everything checked out so apparently that is not the problem. Not easy getting that out with the v-drive configuration. This weekend I plan to purchase a small fuel tank and run the boat off of that to see if it still happens. Only probem is I have to run it out from the dock before this happens and it only happens sporadically so no guarantee I've isolated the problem. I'm at witts end. Anybody ever experience anything like this? Any suggestions for next steps? Thanks.

[RobS]

Have you checked the fuel tank vent to be sure it is clear?
Does she sputter then stall or just cut right out?

[Rx-scape]

I had a shutdown due to air in the fuel filter, Had a service with change of fuel filter it got a a grain of sand or crud in the o ring. When the filter was tightened the O ring would catch and a loop would form enough to let the fuel pump suck air into the filter.
I changed the filter but the crud was stuck in the grove for the O ring still sucked air at plane. It would run slow or idle all day until opened up then would get enough air to shutdown. I found the air was in the fuel filter and purge that the engine would start and run so took the filter off and cleaned the O ring finding the chunk of crud. It has not happened after that.

Lee Rx-scape

[Carl]

How much fuel is typically in your tank? Reason I ask is, last time out fishing I too experienced a sudden "shut down". This happened after trolling for 4hrs at 900rpm. I had just slowly brought it up on plane, and I mean slowly, after trolling I always bring the engine up very slowly to let it clear out, and just after coming up on plane and cruise speed, she acted as if it ran out of fuel, and shut down completely. I had to crank for several attempts at about 5 seconds before it started back up. I then ran it for a few minutes at 1500rpm before putting it back up on plane with no issues for about 5miles to the fuel dock. I have owned the boat since new and this was the first time I had ever run the boat to below a quarter tank of fuel. I thought maybe bringing it up slowly in the heavy chop had caused it to suck an air bubble. I fueled it up and then ran it the 20 miles back to the dock with no issues. I will continue to watch this thread and let you know if this happens again. I hope not.

[Gary J]

Thanks for your posts. I will check the fuel tank vent. Had not thought of that. When it stalls it usually completely shuts down. A couple times it would catch and start to run again but normally it just stalls out completely. I have changed out the fuel filter and gasket. I"m wondering about the hand pump on top of the filter used for bleeding the lines and whether it may have a small pinhole leak allowing air to get sucked in. The fuel in the tank is between three quarters and full. I usually don't let it get much below half before refueling. I am also wondering if it could be something electronic with the ignition shutting the engine off. I tried disconnecting the stop bottom but that didn't seem to make a difference.

[Russell]

You do not mention checking the fuel pump but I would guess your mechanic checked that before removing the injector pump. On automobiles you can have a fuel pump going out and it first shows up by stalling at high speeds on the highway. Dirty fuel filter does the same but you changed those.

[LillianpFD]

I had an issue last year where we determined my injector pump was faulting due to some magnets that eroded in the pump. (2003 yanmar 315). Pump was rebuilt and the boat ran fine and now i'm getting similar symptoms like last year, stalls when I idle down quickly and needs the throttle opened a little to start. I could not idle at all in neutral before i had the injector pump fixed. Had fuel and filters checked leading up to injector pump repair.

[efishnsea]

I think it would be a good idea to check the fuel lift pump to see if its the issue. The engine can start and run off the injector pump but it will starve if the fuel lift pump is bad. I beleive if you disconect the fuel line going into the fuel filter And put it in a bucket and crank the engine it will tell you if its working. Thats the begining of the fuel system to the engine. If its OK then it will have to be in the injection system. Assuming that the filters are alright. Or perhaps it could be a collapsed fuel line.

[Gary J]

Again thanks for the additional posts. My boat does not have a fuel lift pump and never did. ( 2004 315 Yanmar). My mechanic says that the Yanmar spec calls for a pump when the tank is not above the engine. He has purchased one and we hope to try it in the next week or so. The perplexing thing is that the boat has run great for 8 years without it. Did Albin install these typically?

[Gary J]

It appears that we have figured out the stalling problem. It is not the injector pump or the fuel lift pump, which if I even have one it is built into the injector pump. The fuel selonoid closes randomly when the 12 volt current from the ignition is interupted. Apparently there is a short or corrosion in this wire. We ran a wire directly from one of the batteries to the injector and once connected we could hear a click as the selonoid opened, allowing the boat to start right up. Upon disconnecting the boat would usually stall out. Since doing this and running extensively with this wire directly connected there has been no problem. We will now replace the ignition wire and that should solve the problem. Such a minor problem to fix for such a major headache. Hope this info can help someone troubleshoot any similar issue.