A couple weeks ago coming back from a sail i started my yanmar- fired up as usual - motored to my dock and as i entered the slip the motor died I tried to restart, engine turned over, but no start I bled the engine, and started again, the motor fired right up snd ran for 15 min until i shut it down Went out last week and all good Today , at the dock, i started the motor and it ran fine for 10 min and then died would not re-start- fuel shows 3/4 Any suggestions There Is no water in the raycor could a bad alternator do that? Bad injectors? Ray or and secondary fuel filters changed out a couple of months ago. Thanks for help with troubleshooting!
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probably not the alternator. raycors should be clean if it was only a couple months unless you got bad fuel in the meantime. I would disconnect the fuel return hose and blow it out back into the tank with some compressed air and reconnect, bleed the engine again. I had a similar issue with a blocked return line years ago - it made the engine seem like it needed to be bled and I’d do that and it would run for a while and then die.
Thanks for the reply. Forgive my lameness - are you saying disconnect the fuel line to the raycor from the fuel tank and blow that back to the tank?
Sounds like the lift pump is failing or you have an air leak .does it make full revs under load
I replaced my lift pump with an electric one solved all the issues
A couple months back I did my engine maintenance with raycor, fuel filters, etc. and noticed that my lift pump lever wasn’t really giving me the usual spongy feel even with employing my “Camino!” Method of decompressing the cylinders. So I’ll check my oil again and look for signs of fuel in oil, and check the fuel filter and replace. Also when I started the motor today I didn’t hear the “ring” upon turning the key- Hmmmmm…course I can’t hear well nowadays! But…..is that related too?
Lift pump diaphragm can lose its elasticity without being punctured
What happened with mine it initially stalled when throttling it wouldnt run above 1500 rpm
I replaced the liftpump it was ok for a short time then it failed again
Thats when ifitted an electric pump bypassing the lift pump
This is all helpful insight as my engine quit on me last week heading into my slip and had to be towed the rest of the way. Haven’t had a chance to work on it yet but these tips are going to be helpful. Thanks.
Very helpful Bill - on replacing the lift pump - is it just shut fuel line, remove fuel line from lift pump, remove the 2 bolts, remove lift pump, slide in new lift pump, bolts, attach fuel line?
Yes but you will need new copper washers remove fuel line to and from pump
Undo the rwo bolts refit new pump suggest you attach the paper gasket with liquid gasket to the pump as it is fiddly getting it lined up
Once fitted replace fuel lines and prime
To make priming easier i replaced primery filter with one with a built in pump
I ordered a replacement (manual lift) - I’ll re-check the system for air first…. Got to thinking of how this all began - couple months ago doing the maintenance I started the motor and it ran for 6-7 min and died. Turned out I forgot to re-open the fuel shut off valve by the raycor- Did that and quickly bled the motor but did see a lot of bubbles and the lift wasn’t spongy. So…..
Might start with the simplest options first.
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Confirm that the Racor filter housing and bleed screws are tight. Make sure racor is full of fuel. Confirm fuel shut off is fully open. Also Look for any fuel leaks.
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Remove the secondary filter housing and check that it is full of fuel.
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Start at Racor and work to engine. Double Check tightness for all bleed screws in line. loosen and retighten everything. Racor, secondary filter, engine. Check any fittings or hose clamps. Get in there with light and touch and inspect.
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Bleed fuel lines again.
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Try to start engine and run at 1500- 2000 at dock/mooring in neutral for 15-20 mins. Let engine cool and do it again.
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Remove racor feed line and Run a burst of compressed air into tank from confirm tank pickup is not clogged. Bleed fuel.
If still stalling double check everything again.
Then consider a new fuel pump.
Years ago I had a very similar problem
I was motoring up from Monterey and motor stopped just off Pigeon Point, a good couple miles off thank goodness. Very little wind.
I fussed around with bleeding, tank vent line. Lift pump filters, water in fuel.. with no joy.
…a little run time then poof. Very frustrating.
Then I blew back into the tank output line and voila, I got a start and it stayed started. Note: diesel fuel tastes terrible.
When I got home, first thing I did was bought and installed a 6 inch tank inspection plate which has subsequently saved my ass on multiple occasions.
Anyway, when I inspected the tank I found several little nuggets of what looked like pariffin. I surmised one of those nuggets got bounced in the seaway at just the right angle to get sucked up and lodged in the uplift tube. There was enough bleed around this obstruction to allow the system vacuum to pull a bit of fuel through between start go rounds, leading to several sets of starts followed by dashed hopes
This was one of my first “hallelujah I fixed it” moments at sea.
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BTW I also have replaced the lift pump. That was not a hallelujah moment. In that case the mixing elbow was rusted shut 
Aside from the usual suspects, a friend of mine spent years trying to figure out why his engine would cut off sometimes after running quite a while. He put an extra in-line filters, cleaned his fuel tanks bled everything repeatedly etc. It was finally tracked down to fuel lines where the material was soft and the suction would sometimes cause them to collapse. This seems like a pretty rare thing. I’d certainly never heard of it.
Finally back at the boat - racor looked great, secondary filter cup brim full of fuel, - bled all and still wouldn’t start - it would crank and run for 2 seconds and die. Noticed 2 hose clamps loose - return fuel line?- tightened- motor fired up Bled again while motor running - good fuel pouring out so good Started and stopped several times so hopefully that was it 
…..even though I now have extra racor or 2, 3 extra secondary fuel filters, lift pump replacement ready, air filter ready……etc…..and lift pump seemed to push fuel nicely…..