Mercury 2.5M 4-Stroke Mercury Outboard Motor

Update: I just wanted to take a minute to provide an update on this outboard after having it for a couple years. This motor does not like 10% ethanol blended fuel. The carburetor was constantly gumming up causing it to either not run or to not run well. Ethanol free fuel is now available in my area and I’ve started using only that in all my small motors. If you have any trouble with this outboard at all it’s likely the ethanol in the fuel causing those issues. 2 Years ago I decided to replace my old Johnson Colt 2HP from 1989, which still runs great just got tired of mixing fuel. At that time I went with a new Honda 2.3HP Outboard. The Honda 2.3HP 4 Stroke outboard didn't work out too well, it seemed to get too hot and would reduce quite a bit in power performance and was also very difficult to start. I needed a dependable and easy to start outboard so I decided to replace the Honda with this Mercury 2.5HP outboard this year. So far I've nearly put 20 hours on it and it has run flawlessly. I always follow the break in cycle instructions as well which I found to be very easy to follow with the Mercury. The motor runs very cool which I believe is because it's water cooled where the Honda was air cooled. It's also much quieter than the Honda. The Mercury is also faster and more torquey than the Honda equivalent. I always loved my old Johnson Colt outboard and I'm happy to say that this Mercury, so far, has been a good replacement.

Still waiting to use it. Mercury still beats the others.

Two things caused my merc 2.5 hp outboard to start hard and run below max RPM. The first was debris in the gas tank that partially plugged the jets. This microscopic debris was in the tank when purchased new. I filtered the fuel I put in the tank. I removed the carbuerator and cleaned out all fuel passageways with carb cleaner and compressed air. The second problem was a "too long" throttle wire that connected the rotating plastic connector (controlled by the twist grip) to the throttle butterfly valve. The excessive length of this stiff wire dictated that the butterfly valve was 2/3rds open when the twist grip indicator was in the start position. A butterfly valve that is 2/3rds open makes it almost impossible to start the engine. I bent this wire with two pliers and thereby shortened it so that "start" position on the twist grip set the butterfly valve closed and full throttle on the twist grip fully opened the carb butterfly valve. I also put steel epoxy putty in the 1/4" slot on the underside of the plastic disc sitting on top of the wheel controlled by the twist grip so that it rotated in harmony with the wheel controlled by the twist grip. So, in conclusion: There is a person at the merc factory who job is to throw in a pinch of debris into the fuel tank so that merc distributor mechanics can make a living fixing merc 2.5 hp outboard motors and 2). The person installing the throttle connector selected a wire for some other model engine and forced it to fit.

Good motor for a Jon boat, an inflatable or any small boat. Motor came through defective. After a year I had them replace the head. Nor problems since. Only negative is that is sometimes hard start once it's worm. Might take 8 - 10 pulls to get it start. Once started it runs well.

The motor performs great really good in shallow water got about 15-18 mph on a 12 ft jon boat had massive torque for a four stroke to really good motor been having mine for abou 3 years and stills runs ans starts great