Mercruiser 260 stalling out

A

Anacapafish

New Member
Mar 15, 2009
39
channel islands ca
Boat Info
225 Express Cruiser 1980
Engines
Mercruiser 260 MR Drive
Hey folks, Got her out a few weeks ago for the first time in 14 month restore ran beautifully no problems at all. SOOO... we planned another trip abit longer and got under way. About 20 minutes into our departure at 2200 rpm (the first time) it dies... Uh Ohhhh. Gave it a minute or two, started right up and away we go, a bit slower as I wanted to take it easy and really pay attention to how she sounded and felt. Died again, this time at maybe 1800-2000 rpm. Shut her down for a few minutes and well... you know the rest... this is how I got back to the harbor. I'd like to troubleshoot this asap. Any suggestions or similar problems? How high should the amp gauge read at regular operating conditions. Mine was reading about 25. I did not have any auxillary items on at the time of operating except vhf and fishfinder directly to the battery (fused) same as before. Could it be fuel pressure or a fuel pump?. Always appreciated
 
Does it stay running at idle in the slip? How does it rev in neutral?
 
Fresh gas? Did you check the water/fuel separator?
 
How did it die?
THIS IS THE QUESTION

Like the switch was cut off? and just cut slap out?
Or slugged and chugged out?
Electrical Faults will most often be abrupt.
Fuel problems will fade out.
 
On my 81 DA it turned out to be a bad connection in the wire harness above the engine. the male and female connectors had to be cleaned and the grip had to be adjusted by bending them with a tiny screw driver.
 
Yes it cut out abruptly. I let it sit for a few minutes and would start up right away. The carb has been completley rebuilt and has only about 2 hours on the rebuild, so I wouldn't suspect that, however the water fuel separator has alot of flakey scaley residue in it, I'll change that as well, but I dont think thats it. It would priobably as you said chug and sputter if it were a dirty fuel issue. Thanks for your responses, they are a big help, keep em coming. Thanks again.
 
check the volts at the battery. they should be no more than 14.7 and no less than about 13.5 with the engine running.
 
I would replace the fuel lines and the fuel/water seperator. With my boat, since the ethanol switch, the fuel lines become spongey and don't allow the fuel to pass freely, hence the stall. I replaced those and no more stalling. I also grabbed a bottle of gas treatment incase there was water in my fuel and she's been great (knock on wood) since. Good luck! Let us know how you make out!
-Heather
 
I think it's electrical. I do I do,,

I would, If it were me I would do this,

Run a hot wire to the coil and take it for a spin.

If it cuts out still, it's in the ignition system at the engine maybe a bad coil or in the distributor. Then depending on the out come, we eliminate things one step at a time.

PS, don't leave that hot wire hooked up for any time if the boat is not running. It will burn the points out.
 
First off take a nail file and clean up the points a little. Second buy a 15 dollar spark tester, the type that goes inline with the plug wire. Run the boat with the hatch open and see if the Light from the tester starts to dim when the problem occurs. If the spark stays consistent then u are good with ignition side. If the spark stays consistent I would start aiming toward fuel pressure or a plugged fuel tank vent. Dan
 
Excellent advice so far. 25 on the ampmeter is kinda high for a constant reading. Mine may START that high upon start-up, but steadily comes down to zero inside 15 minutes.
ALSO, see how hot your coil is getting. It should be warm, but NOT hot. If it's hot when your engine dies, you very well could have an internal short in the windings of the coil. The bracket that holds my coil bolts directly to the intake, so it's transfering that heat to the coil as well. I removed the coil and added a few wraps of electrical tape around the base where the clamp holds it to insulate it half-assed from engine heat.
Just my 2 cents; and that's about all it's worth. ;)
 
Ok! Got the fuel water separator top off and the filter was filthy, I mean bad! Removed the bottom and about at least 1.5 cups of crap was in there. There is a second fuel filter screw on type between the fuel pump and carb. It was not good either but much better than the one between the tank and the fuel pump. This is one of those embarrassing moments of "UUHHH I was certain they were checked".

Prior to our last outing, 38 gallons of fuel was added. I believe theres a high probability that when the fuel was added and the boat taken out of the harbor shook alot of stuff up in the tank, it filled and glogged the fuel flow to the carb, when the engine died and was allowed to sit for a few minutes the pressure in the line lessened and the debris had a chance to fall back to where it came from, motor starts up and goes untill the debris stopps it up again.

We put new filters and cleaned the canisters thoroughly, I will check them after the first hour of operation to see if there is any junk being pulled from the tank and go from there. Hopefully she'll run fine, sounded great with the muffs, good to go. Thanks all responders! This site is the best.
 
Another quick note, I am not ruling out the possibility of something electrical being the stall problem, but with the fuel system in the condition it was, I will take her for a sea trial and find out. Alot of the electrical on this boat looks great, tidy clean and organized, and there is some that is spaghetti (mainly under dash) that needs to be gone through and organized (not my specialty).
 
IT'S Back! Thought I had this fixed with the fuel filter replacement and fresh gas and so on. The boat did fine for 2 hours and then...same thing, it shut down, motor died, waited a few minutes and started right up, ran for a minute or so and died.
This is probably the most frustrating type of malfunction-intermittent. There has been little oportunity to establish any kind of pattern. I like my mechanic BUT will get a second opinion from a different mechanic who has "fresh eyes" for this boat.
This type of issue is discouraging and makes for unpleasant outings as the fear of stalling out is constant and burdensome. I like the boat and need some direction. Where is the best place to begin full troubleshooting and testing of systems? I noticed again the amp gauge is at or slightly above the 25 line on the gauge during problem periods. I took note that when we were motoring out for the first two hours the amp gauge was at or just slightly above 0. Something is not right in this area. Coil? Thanks for the help this site has taught me more about boats than anything else.
Help me get this problem licked so I can fish peacefully!
 
Just wondering if i could get some response and bring this thread back to life. The prob still exists and i'm looking for a little direction. Maybe a complete troubleshoot of the elect and fuel systems?
 
Here's a thought:

Your undetermined weather it's fuel or electrical. That amp draw may be something.

Unfortunately you'll have to take her out again and recreate the problem. Stay on the throttle and let it die good. Right after it dies and the engine is dead, pull the hatch feel how hot the coil is. Then pull the flame arrester and work the throttle a few times to check the accelerator pump out put. First pump will empty the AP well and second will have to get fuel from the bowl. This test should at least tell you weather your carb has any fuel in it or not.

Don't know if you've still got points or not, but I would be running an electronic ign system for sure.

Be careful with this one my friend. Double check your safety equipment and be prepared. Lift that hatch cautiously when she dies or maybe check through the fire suppression cover first.
 
Yes the points are gonna go soon. Elect Ign is overdue, will also replace coil at the same time. BATTERIES: I have two different batteries in the boat-I was told by my mechanic to run on BOTH-But.....I also heard or read that batteries themselves can have an internal short in them that can cause the same behavior. I am going to match the batteries so there will be no doubt. I have right now one battery that is a 750cca and an 1150cca, If the switch is in the BOTH position could this cause an uneven charge or malfunction in one battery? I think I'd feel better if I had two batteries of equal size (1000cca or higher) for consistency and simplicity and run the boat on 1 or 2 . Thanks BonBini for keeping this thread alive and your help is appreciated.
 
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