Loss Of Rpm At Full Throttle

[KCJ]

Mercury pro xs 250, 2013 model. Runs 5600 rpm at full throttle. Motor will drop 3 to 4 hundred rpms then pick back up. Ran 5800 rpm before with no drop. What can cause this problem???

 

[firedog978]

The most likely reason for what you're describing is the in-line bulb of the fuel line.
Those bulbs are notorious for breaking down and losing suction. Especially, at full throttle.
They're in-expensive and simple to replace. Try that and I think your problem will be solved.

 

[KCJ]

Thanks. Changed out the bulb but now will not pump up tight. Started fine and idles with no issues. I will take it to the lake in the morning. I will let you know how it works.

On the lake now worse than before. Down another 200 rpms. When you stop and fish will not hold pressure. Requires you re-pump the bulb. All connections are tight.

 

[iburypaul]

Thanks. Changed out the bulb but now will not pump up tight. Started fine and idles with no issues. I will take it to the lake in the morning. I will let you know how it works.

On the lake now worse than before. Down another 200 rpms. When you stop and fish will not hold pressure. Requires you re-pump the bulb. All connections are tight.

I've got the same issues, interested in responses