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Engine stall and dying out at cruising speed

swat784

New member
I have a 1994 225 3.0 mercury outboard (carb)....Went out yesterday. Idled fine at the ramp...Throttled up to a certain point and the engine began to sound as if it were dying and going to shut off (like it wasnt getting fuel)...throttled up a bit higher and it ran fine. did this several times when the throttle was at same position. RPM gauge doesnt work right now so I have no idea what they were... Throttled down to idle several times and it stalled. Turned and went back to ramp and it sat idled perfectly while waiting to back the trailer down the ramp. Flushed when I got home and still ldled fine.....Had fresh gas. Have no idea where to start looking. Any help would be much appreciated.

Thanks.
 
Changed fuel filters and spark plugs lately? Fuel pump may be worn. This is what I do when it runs a little rough. Change the plugs and filters if needed. If it has a fuel/water separator remove it, dump out the fuel into a jar to see if there is water. Treat the fuel if a little water is found. Refill the filter or a new one w/Seafoam. Run the engine on muffs for 10 mins. and shut it off. It will smoke alot...it's normal until all of the Seafoam burns off. Wait overnight and fire it up. It should run much better.
 
I assume the air vent was open, and even if the tank(s) are built in? Fuel can't be sucked out if the air can't get in. What you experienced is typical of a not vented tank.

Jeff
 
ok....got to everything tonight....sea foam plugs everything....still idled fine but as soon as i throttled up it began to die out like it was starved of fuel....Checked primer bulb while throttled up and it had little to no few in it.....???? open the 2 small deck hatches over the fuel tank...saw no vent....where would vent be on a built in tank? Should the primer bulb be full when throttled up??????
 
Look for a small hose coming off the tank, usually goes to a screened fitting through the hull.--------------Some to the side and some on the stern depending on where the tank is.---Primer bulbs do not need to be hard once motor is running.---------You might want to inspect fuel system beteen the primer bulb and bottom of tank.-Possibly a bad anti-siphon valve as well.
 
Hit the choke when it starts to die...if it takes off then you may need to rebuild the fuel pump...has it ever been rebuilt? The vent line should be about a 3/4" black hose next to the fuel filler hose. If it does not have a separate exterior vent you probably have a combination fuel fill/vent cap. The vent hose will be connected at the filler hose. Primer bulbs are just manual fuel pumps and should not stay firm after the engine starts.
 
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