92 mercury 25hp full throttle problem

[ad870]

I took my boat out to run it the other day and it started fine and ran fine until I got it up to full throttle. It is a tiller steer model.

Once at full throttle it acts like it is "bogging down". It will run and full throttle then back off then back to full throttle then bog down again. Sorry for the vague description but I'm about as far from mechanically inclined as they come.

A buddy mentioned that he thought it might be the carb. gummed up and that I should lightly tap it with a hammer while running and see if this helps.

I thought about using some SeaFoam in it.

Any ideas or suggestions before I take it to the shop?

[mercury89]

When this happens again try squeezing the primer bulb while the engine is running and see if the problem goes away while the bulb is being squeezed.

This happened with my uncles motor and it would go away if you squeezed the bulb.

IF the above is true then the problem is most likely the fuel pump which would not be hard to overhaul yourself, purchase the rebuild kit for the fuel pump with the diphragm and the seals, get a shop manaul and follow the steps to take apart the fuel pump, then reassemble it with the new parts.  That should fix the problem.  If it does not post back and we'll look into another solution. Good luck!

[Raul]

The most probable cause is in the fuel system:

Before the outboard:

1.- Tank not getting enough air

2.- Bad bulb

3.- Bad connector

4.- Broken hose

5.- Choked hose

In the outboard:

1.- Bad hose or choked hose before the filter

2.- Choked filter

3.- Bad hose or choked hose before the fuel pump

4.- Bad fuel pump

5.- If it 's not fuel injected then the carburator has a problem, there are two tiny hoses that take fuel from the pump and drop it in the carburator, those hoses with time crack and allow air to flow in with the fuel reducing the ammount of fuel needed.

Want to hear my recommendation ? take it to the mechanic.

Had a similar problem with my outboard but it happened when I went down from full throttle. But since I 'm brave, bold and stoopid I tried to "fix" it myself and in the process I screwed up the fuel pump, instead of 25 dollars I ended up paying over 300 for the repair.

I'm about as far from mechanically inclined as they come.

Don 't feel bad about it, that makes two of us.

[HPBB]

This may sound stupid. But make sure your vent is open on your fuel tank. This happen to 15 merc I have, did exactly what yours is doing.

I made sure the vent was open. It was all the way open. well on that old tank all the way open, closed it again. I found that out the hard way. this little mishap cost me new a carb. If this isn't it. I would have it checked out. better safe than sorry