I have a 2004 Mercury 4 stroke (carb) went out today. Idle great when I would get on it around 4500RPM motor would bog down them try to catch back up. Never had any issues before. Fuel filter?? Carbs need to be cleaned??? Any advice would be greatly appreciated!
Same problems with mine. Make sure your priming bulb is tilted up a little bit. Level or pointing down will “starve” the motor of fuel. Give it a try…its free.
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Same problems with mine. Make sure your priming bulb is tilted up a little bit. Level or pointing down will “starve” the motor of fuel. Give it a try…its free.
I had never thought of that before, I just went out and cut my hose shorter so the bulb was pointed up towards the motor. Maybe that is why mine takes 3 or 4 starts before it keeps running.
SEAFOAM, ALWAYS…NOT EVERY TANK BUT FOR SURE WHEN YOU STORE IT.,,RUN A COUPLE TANKS THRU 
I had the exact same problem with my 2004 Mercury Optimax, it turns out I didn’t have ethanol resistant fuel lines and the ethanol had deteriorated the lining inside my fuel lines and plugged the fuel line, bulb, and fuel filter. After I changed all three of those items it runs like brand new.
If you have a Mercury motor and have anything other than the new ethanol resistant lines (Gray with BLUE Writing), you need to change the lines, bulb, and fuel filter.
All of the above make good sense, but also check your spark plugs.
Had the same problem with my 2002 115 Merc 4-stroke. Changed plugs, problem solved. Plugs are very reasonable at Mills.
It sounds like fuel starvation.
I would not add a bunch of needless junk to the fuel unless you have a problem that additives can solve. Seafoam is a detergent. It only helps if you have a problem caused by fuel or combustion deposits.
Here’s what I’d do:
1. Replace the fuel filter and (unless you’ve changed them very recently) the spark plugs. Make sure the plugs are gapped correctly before installation.
Test the outboard.
2. If that didn’t solve the problem, I’d suspect an air leak. The thing to keep in mind with air leaks is that it might not be the obvious, the hose between the tank and motor. This is the most likely, but it could also be the fuel lines under the cowling or it could be the dip tube or tank fitting.
Visually inspect the fuel lines under the cowling and if there is any cracking or visual damage, replace all of them.
The easiest way to test a tank assembly is to get a totally separate tank and hose assembly from someone else and then do a test run while changing one variable at a time. First just try the different hose. Then try only the different tank with your hose, etc.
Grouse
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