So when I got the mercury 500 outboard engine unsized I read up on that a good next step was to clean out the carburettors so I decided my next move was to get to that!
There are two carbs on this engine and it didn’t take long to figure out that they could be taken of without starting to get other stuff off first.
That includes disconnecting the wires that all lead in to a box behind the front cover of the engine. I didn’t want to do to much with the wires since they are old and easy to break so I took it very carful when I disconnected them and befor I did that I took a few photos so I knew where they all where suppose to go back again when the cleaning was done.
The carbs then self was only fastened to the engine by 4 bolts and and you have to disconnect the choke as well but that was very straight forward.
When I hade the carbs out it was time for the cleaning, and by opening them up it didn’t take long to see they where in need of a cleaning. Especially the part where the float is, white gung was in the bottom there. I couldn’t find carb cleaner but read break cleaner worked good and it turned out it was break cleaner my Lokal marine uses to so I bought a can of that.
A good advice when cleaning the carbs is to use protection glasses, when you spray in to one hole you don’t know where it will come out and you don’t want this in your eyes.
Apart from that a god tip is to have small trays to put the screws in order when you take them out, it makes it easier to get it all together again, I was going to do a video of this job but it turned out I did a time laps and it was to fast to get a idea of what I was doing.
There is a needle that is set witch I believe determines how much gas/air the engine gets. This one I counted the turns in to full (gently so I didn’t damage the needle) before I took it out to clean inside. Now I could get it back to original position again. I believe this is the Ones I need to mixture with to get my rev down but I know I have them in the same settings as they where before so the high rev was probably a problem for the old owner to. Fortunate these setting screws are accessible without taking apart anything from the engine again.
On the lower carb I couldn’t get out two brass screws because someone hade been on then with bad screwdriver before but I think I got all the dirt out of them from the other end anyway.
When the carbs where out I took the opportunity to clean the inside of the engine where I could reach as well and before building all the parts back into the engine I orders two gaskets for the carbs.
Putting it all back into the engine was pretty easy now when I knew where everything when and using my photos as reference. I believe most people can manage this with some patients and doing it methodology and paying attention to what the do.
Where the carbs sit, this had a lot of dirt before but did spend some time on cleaning it all up and made a big difference. Also the new gaskets in place.