Yanmar stops in waves

[PaulvR]

Originally Posted by ericoh88

Not sure if a day tank could prevent the problem - yes no?

...not if it was dirty :-)

[Squanderbucks]

Check the electrical connections first ( not likely but needs ruling out). Then Dump out all the remaining fuel in the tank and clean it out. If this is a removable flexible tank consider removing it from the boat to fully flush out with clean fuel or some alcohol. Maybe consider turning it over and letting gravity help make sure nothing is staying in the bladder.

Also if the vent is clogged the bladder could collapse and be sucked up closing the fuel pickup as the bladder flattens.

[Mal Reynolds]

Having cleaned a tank by removing it and using muriatic acid, I would just replace the bladder. You also want to replace the o-ring at the fill where the water may have entered. Also check the vent to see if water could have entered there.

Put the o-rings for the fuel and water fills on an annual replacement schedule.

[Paul Howard]

Fuel sloshing can create foam in the fuel creating an airlock, usually the engine revs surge and falter and then engine dies, just as it would if there were an air leak.

Not sure what happens with a self-bleeding engine fuel pump.
I had the problem on a boat with a long fore-and-aft flat bottomed tank and had to re-configure and baffle. When the bow plunges and buries while motoring into large seas and the boat almost stops, bow rises up and boat accelerates, there is a lot of sloshing.

[Horus]

What about the water separator/filter? Is there diesel in it or.......water? When you have a bit water in the tank and the tank is shaking in waves, the water can be picked up to the outlet of the tank. So your engine is probably picking up water instead of diesel on wich it won't run. On flat water the water stays below the outlet level in your tank and the engine runs as it has to!
If so, check the filling cap and air outlet of the tank; if both are okay, the water comes from the biocide diesel you probabably are using. In that case you have to drain the tnk more often.

[ericoh88]

Is it possible the cause is air leaking into your fuel lines? Violent shaking of the boat may bent or flex the old hose to leak air or at the joints?



Maybe consider replacing all the old hoses and hose clamps?

[AA3JY]

Originally Posted by AA3JY

Had similar experiences..plugged pick up tube from debris in fuel tank..ended up using positive pressure (mouth)through (disconnected) fuel line..yukkkk

Yes..in the end dumped a portion of the fuel though back washing the tank and fuel polishing procedure..

‘Shaken but not Stirred ..’ Go through one one these (Derecho front) and one will find how clean ones fuel tank is..as noted in my original post...

[chrisr]

we have a pair of 4JH2TE's, and had exactly the same thing happen to us...but it just so happened that it was the same day we had picked up a big coil of rope around the other prop...so when the second engine stopped it was 'interesting'

ever so pleased when it fired again without any problems few minutes later !

the engine has run perfectly before and since

was a rough day, but there was abt 1/3 tank (80L), and we've been in worse with less

engine stopped quite quickly when we hit a particularly bad 'pot hole' and i put the stoppage down to this heavy jolt, but that still doesn't really explain it

basically the only thing that will stop a diesel like that is fuel...but ????

cheers,