1999 20 hp Mercury 2-stroke Keeps Shutting Off

[scumfrogmillionaire]

1999 20 hp Mercury 2-stroke outboard:

Was out on a small river this past weekend and my motor would run perfectly fine for about a half an hour, then just completely shut off anytime I wanted give it throttle. I could still idle just fine. I’d turn it off for about an hour or so and then it would run fine again for a set period of time. Water was spitting out so impeller is working BUT the water temperature was around 87 degrees with daytime temps in the 90’s. It did not make an audible alarm (not even sure the alarm works anymore since it never went off when I blew an impeller last year). When it shuts down, it doesn’t sputter, just loses power until the motor is completely off. Any ideas?

 

[Dos_Enchiladas]

boss i think i found somethin useful

How to Repair Your Engine When the Engine Will Idle but Dies at Full Throttle | Engine Repair

If your engine engine will idle but dies at full throttle, you'll need to check the carburetors, air filters, and more. Our troubleshooting and repair guide can help.

www.ereplacementparts.com

 

[Faztbullet]

Off in like kill switch pulled or slows down to nothing ?

 

[scumfrogmillionaire]

Off in like kill switch pulled or slows down to nothing ?

It just slows down to nothing. I can start it back up and it will idle fine. Start giving it throttle and it shuts off. No bogging or sputtering whatsoever.

 

[flyingscott]

Is this a tiller or remote model?

 

[scumfrogmillionaire]

Is this a tiller or remote model?

Tiller.. I disconnected the fuel hose and the inside of the hose is all clear plastic-like liner that seems to be falling apart and clogging it (attachment). I'm thinking this might have something to do with it? Not sure why it would run perfectly for a set amount of time though.

 

[Sea Rider]

Been there with a fuel hose thar dove me extremely nuts for quite a time. That fuel hose is crap, with age will break in tiny pieces spacially if being a double sleeve fuel hose. Clean the carb's fuel filter and install a new fuel hose.. The motor misses more as speed is increased due to fuel restriction when more fuel is needed to maintain the motor alive.

Happy Boating​

 

[scumfrogmillionaire]

I really hope replacing this Attwood Fuel hose will do the trick. I tried prodding around with a screw and I can't even get past the separated liner. IT almost collapses inwards and clogs everything up. I want to say that this hose is only 3-4 years old.

 

[Sea Rider]

I want to say that this hose is only 3-4 years old.

It's not the age of the hose, but the quality of it and the material used that seems doesn't handle well E fuels. For peace of mind better install an OEM Merc fuel hose.

Happy Boating​

 

[flyingscott]

If it doesnt try disconnecting the kill switch in the tiller.