Outboard issues

1998 merc 115 elpto coastal. Runs great at first then usually on the way back from around 6 miles out in ocean running 3/4 throttle starts to die. Has done it twice now. Has a small plastic water separator with metal screen in it. Both times found a little water in it. Fuel bulb won’t pump up that hard and kinda goes flat while squeezing but only when this motor issue happens. Any other time it feels fine. Motor runs awesome on the way out but usually only at half throttle due to swells. Had carbs re-built, new fuel pump, new line from fuel separator to motor. In fFlorida and need Help??? Thank you

If your priming bulb is flattenig you either have a blocked fuel pickup, your bulb has faulty valves, or your fuel tank isn’t venting. Test your fuel cap. If it has a manual vent, make sure its open and unobstructed. Good luck.

Possibly a hairline crack in your fuel line you must have an air leak somewhere in between your tank and the motor. And like CRC said a venting issue. Or your fuel filter is dirty? I’ve had some issues in the past and found out I had some debris in the fuel tank and was restricting the flow of gas when the motor was at speeds higher than idle. I’m no expert but just throwing out some ideas ….

I have one of the metal screw on flush caps. I will check the vent on the side of boat and the fuel lines. Fuel filter is clean. Thanks for the help. I’ll update as I go.

I had a flat bulb =–it was caused by the innerliner of merc. gas hose collapsing–replaced hose and good to go

Also the fuel line coming out of the gas tank has a check valve in it. Check it for contamination.

Gundy

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I had a flat bulb =–it was caused by the innerliner of merc. gas hose collapsing–replaced hose and good to go

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This would be the first place I would check. Happens way to many times to the old fuel lines. The inner liner starts to let loose and starts plugging stuff up.

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I had a flat bulb =–it was caused by the innerliner of merc. gas hose collapsing–replaced hose and good to go

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This would be the first place I would check. Happens way to many times to the old fuel lines. The inner liner starts to let loose and starts plugging stuff up.

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Very true.

Two of the most useful diagnostic tools you can have are a complete fuel hose/primer bulb setup and a second fuel tank.

By switching out first the hose, then the tank, then the tank and hose together, you can isolate and diagnose almost all problems related to plugged hoses, air leaks, bad primer bulbs, cracked dip tubes, contamination, plugged fuel filters, etc, etc, etc.

I write a date on my fuel hoses and fule filter/seps with a Sharpie marker when I buy them. Makes it quick and easy to see when a hose has been on there just a little too long and therefore should be Suspect #1 if there are any issues.

Grouse