How To - Free Outboard Service

After I realized how easy is was to check the vitals of my motor, I started doing it pretty often. My motor hadn't run right since I got it. It would never idle. To put it in gear I had to throttle down, shift, and throttle up before it died. I finally got tired of it and tore it apart to clean. The carb was way easier to clean than I expected and now I can idle around without the fear of it dying every time. The main problem with my starting/idling was due to the throttle control arm which I will explain below.

Honda BF15 four-stroke.

Not much going on inside.

Disconnect the fuel supply.

Drain the old gas from the carb.

Move the hose clamp back to release the fuel line.

There are two bolts to remove the carb.

Pop off the clasp to remove the choke control rod.

You will have to put the motor in gear and turn to full throttle to take off the throttle control rod. Hold the throttle arm on the carb fully open with the right hand while doing unscrewing the bolt.

Take the carb to a clean work area and take the 4 screws off the bottom.

Remove the pin holding the float assembly together and the two screws in the center.

This is what it will look like with those items removed.

Keep track of how the innards go back in.

Put on eye protection, remove all rubber components, spray with carb cleaner, and blow out with compressed air. Put everything back together in reverse steps of taking it apart.

Be sure to put the rods back on the carb before bolting the carb down. Getting the throttle control rod in the correct position is crucial. This was one of the main problems I had in the beginning. There was no difference between Idle and Start on my throttle positions. You want the control rod to just finish releasing the spring on the carb when you hit bottom of throttle. I have marked mine so I know where it goes.

Make sure to get the carb drain tube into the discharge hole.

No choke position. If the throttle control bar is not touching the black plastic, your Start throttle position will not be high enough. If the throttle control bar is not fully seated when the throttle is all the way down, your idle screw will not work. 

Full choke position. You can see how full choke bumps up the throttle a bit off the throttle arm.

Take the spark plugs out for inspection.

Gap should be .024 - .028. One of mine was barely .022.

Never run your motor out of the water.

Since I am not at the lake I use muffs.

Put the throttle in the Start position and crank it up. Make sure you have good water flow through the cooling system.



After warming up a bit, turn the throttle down to Idle. Adjust the idle speed screw to the desired level. All these adjustments should be relatively close to what they were before.

With the desired idle achieved, adjust the idle air screw back at half turns until the motor runs the smoothest. A good starting point is to screw all the way in and then back it out five turns.