50hp mercury issues

[Joshua Stansbury]

I have a 50hp mercury outboard that starts up and runs, but spits and sputters under load, any ideas what's going on, or where to look first?

 

[airshot]

No one can see or hear your motor, nor do we know what model and year it might be. In most cases, you start with fuel issues, clean fresh fuel in a clean tank with filters in place. Compression testing with real honest numbers. Spark test with a gap tester tool, not expensive. How long has the motor been setting? Pics or videos do help.

 

[MDCrappie]

Like airshot said - need lots more info to diagnose, otherwise it's just guessing.

 

[JL8Jeff]

When you say under load, do you just mean it's in gear at idle or when you're giving it some amount of throttle? Definitely post the year, model, 2 stroke or 4 stroke, etc.

 

[Pappy]

Agree. No need to start troubleshooting before a lot more information about the issue is produced. Running in a barrel? on a boat? What was done to the engine? Engine new to the OP? More information the better or it just turns into another internet guessing game!

 

[Riverdog]

When is the last time you changed the fuel hose?

If you have one with the liner inside, they can separate and close under load after a few years. Try a new fuel line and a tank with 100% fresh fuel.

That's where I would start first.

 

[scleveland]

My 40hp mercury 4 stroke was stumbling off idle first trip out when you tried to give it throttle, I changed out the gas to new rec 90 and put in new spark plugs problem solved, I hope this helps