Re: 1988 125 Force
For more speed, You can put the engine on a smaller boat LOL
Seriously though. the first thing you need to do is check compression to be certain the engine is healthy. Good compression would be around 145 PSI. Poor compression would be one cylinder or more below 60 PSI or a difference of more than 10 PSI between cylinders. A cylinder at 20 or less would indicate a rebuild is necessary.
Next, check the carburetors to see if they are opening correctly. Watch the tutorial video at the to top the forum.
Check the current prop to see if the engine is overpropped or underpropped. The correct pitch prop will allow the engine to reach 5000-5500 RPM at full throttle. If you do not have a tachometer, you can either search for a 20 pole tach and permanently mount it in the dash or you can buy an inexpensive tiny tach with which many here on the forum have had good results. I have never used one.
Now if all that checks out well and you are still getting low speeds you can do some internal modifications and change to aftermarket reeds ( which I believe really don't do much). You can port the bypass side, but porting the exhaust side will actually yield less horsepower. Porting is the procedure where you manually grind the ports square, increasing the area and allowing the engine to make more horsepower.
Here is a 14 foot boat that delivers 60 MPH with a stock 125 and a 2 to 1 lower unit. Yeah, for reasons best left unsaid, the decal says 85.
However, understand that there is no magic bullet. I experimented for many weeks and months before I hit that speed. Understand that this boat is small and light, allowing the engine to push it fast. On a bigger boat It simply will not go that fast. It is basic physics.
On the forum, we can tell you some hints, but ultimately you must be motivated and do the work to get the most out of your engine.
