Engine Shut Down

[RON SCHERER]

Well, it happened again. Mechanic fixed ground to the fuel pump, and off we went thinking the shutoff prob em was fixed. Sailed down San Diego Bay, turned around at the same place and started motoring back at 2000 RPM. It took approx. one hour to get back to exactly where we were last time and right on cue the engine slowly shut down. This time it would start o.k. but wouldn't stay on. Called Vessel Assist. Kept trying to start Eng. but it would not stay on. Gave up and started sailing in circles for about 20 min. until V. A. arrived. Thought I would try one more time and low and behold it started and run like a new one all the way back to the slip. I'm going nuts as you can imagine. Hey guys any ideas????  I have a 1987 boat and M-25 engine.  

[Stu Jackson]

Ron's EARLIER story can be found at:

http://www.c34.org/phpbb/viewtopic.php?p=11896&highlight=#11896

Ron,

You didn't mention what, other than the ground on the fuel pump, you did about all the input from that last post.

It sure sounds like a fuel problem, still.  Have you checked ALL the hoses, etc.?  No need to repeat earlier comments.  Please bring us up to date on what you DID do, so maybe we can help some more.

[RON SCHERER]

Stu---Thanks for getting back. I did nothing else after the ground was repaired. I thought that was the end of the problem and I could sail (motor) off into the sunset. What happened in a 20 minute time span that allowed me to start the engine like nothing ever happened and go full power back to the slip? It seemed as though after the engine rested for 20 min. it was ready to work again. All I know is we plan to head up the coast in a month and over to Catalina and with this situation I will not leave San Diego Bay until its resolved. My final ? is has anyone out there experienced these exact symptoms and if you have what did you do to remedy the problem?????

[Ray & Sandy Erps]

If the engine temperature is normal when this happens, I suspect it's still a fuel problem.  I'd check the screen on the fuel line pickup tube first.  Could be a chuck of crap is sloshing around in the tank and plugs up that screen and tube.  When the engine quits, the sloshing fuel in the tank washes if off the end of the tube until it plugs up again.

I'd replace the secondary fuel filter.  It could be that the RACOR is such an obvious filter to replace that the secondary filter has never been replaced.  You mentioned earlier that it was recently serviced.  If you're sure that the secondary filter was replaced then I'd probably skip that step.

Could be the RACOR is plugged again or sucking air.  I'd have a new RACOR filter on hand and take it out after completing the above task.  If that didn't take care of it I'd try two more things.  I'd replace the RACOR again, check all the fittings on the RACOR including the little bleeder fitting on top, the little priming pump handle on top and the O ring on the bowl to make sure they are not the source of an air being introduced into the system.  I'd buy a short section of clear vinyl hose, same I.D. as the fuel return line off the back injector and put that in place of that short section of fuel return line so I could see how much air is in the fuel system while it's running.  I'm not sure if those hoses are fuel compatible over a long period of time, so I'd switch back to the original line once the troubleshooting is done.

Those are the easy things to check first and will most likely take care of your problem.  

If it doesn't take care of your problem, there is one more thing to check and that's the valve lash.  I've seen an engine with the valve lash so tight that the expanding engine componets on the warmed up engine began to hold the valves open a little bit, causing low compression and loss of power and hard starting.  I don't think that's the problem in your case, but it may be something that needs to be ruled out if all the fuel stuff doesn't take care of it.

There are other possibilities, but the more common problems need to be addressed first before checking the less common problems.

[Ken Juul]

While you are checking things make sure the fuel vent line is open.  Fuel won't come out if air can't get into the tank.  Insects will build nests in the craziest of places.

[Ken Heyman]

Ron,

Also keep in mind, per previous posts and links, that if your tank is at least half full, you will be getting fuel to the system via gravity. Therefore the fuel pump ground issue would not likely explain the problem. I agree with Stu and others that the issue is likely related to fuel starvation (clogged filter and/or pick up tube screen). I would start with a Racor filter element change and remove the screen from the end of the rubber pick up tube in your tank. Take a look at the picture of my pick up tube immediately after being pulled from the tank(posted a couple of weeks ago).

Good luck,

Ken

[Ron Hill]

Ron : I still think that you've got an M25XP, but that's beside the point.

Did you pull the fuel pickup tube as I last recommend?? and see if there's a screen on the end or in the flexible hose attached to the pickup tube??  REMOVE that screen!!!
It sounds to me like you've got just enough fuel in the lines & filter to keep the engine running for about 20 minutes.  

The next check you can make is to remove the fuel line to the injector pump at the engine filter outlet.  Attach another long 3/8" hose to a it and the open end into a large bucket/fuel container.  Turn on the key switch and the electric fuel pump should fill the container till it overflows.  Now you know that the injection pump is getting adequate fuel.  BTW, the injection pump is one of those items that once running with adequate fuel will run "forever".