Mercury 25HP Issue....Any advice appreciated...

[jeepguy]

I have a 1987 Mercury 25 HP Motor. It starts just fine and runs pretty darn good for the most part. Here is my issues...

Seem to run hot...

Is the water "peeing" out supposed to be hot?

Run good at full throttle for a bit then slows or "bogs down" for a few seconds then gets back up to speed, and repeats this process.

Any answers or advice would be greatly appreciated.

[RebelSS]

Sounds like your "bog" issue is related to possible fuel delivery problems....check your fuel lines/bulb/cap for pinholes. When it bogs down at WOT, give the fuel bulb a squeeze, if it picks right back up, could be pinhole in your diaphragm. (Had same exact problem)

Yes, the water should be really warm...not really "hot", because it's pulling the heat from the water jacket surrounding your cylinder head. Hope this helps.

[jeepguy]

When it bogs down I gave the ball a squeeze and it seems to flood the motor. Anything else anyone can suggest. I think it is time to drop it off at an outboard mechanic.

[BoxMN]

Sounds like you are running out of gas in your carb bowl. I.e. at full throttle it needs more gas, but it is using it faster than you are getting it from the tank. My guess is a good carb cleaning, possibly a new carb kit (about $15-$20) that has new seat and needle etc. would help. Make sure you put the float in the right side up - I did it upside down and it was the same symptoms yours is having - it wasn't letting enough gas throw at higher speeds. It really is pretty easy to do, hardest thing is get at the nuts holding the carb(s) on p i.e. starter or recoil in the way.

Good luck.

[jeepguy]

Yeah, when I take the cover off and look into the carb and turn the throttle (with motor off) the flap (butterfly) doesnt look like it is open all the way. I woul dthink it is supposed to go completely flat. I think one issue I have is an old gas tank. The pickup tube has fallen off numerous times. I am going to go get anew tank @ fleet farm. Not that that is the fix. Could it be a linkage problem? I mean twisting the throttle wide open and there is still room to go.

[Surface Tension]

If the pickup tube is falling that means you have a bad connection and sucking air.

Get the new tank or re-place the pickup tube and new clamp.

[jeepguy]

I am going to go get a new tank. It just occured to me...it was running great, then I had to store it outside for a weekend and left the plug in and the boat completely filled with water. I would assume water got in the tank and this could be my issue. I have since used seafoam, but I have a feeling a new tank could only help.