What do I need to change to make my 15 hp honda into a 20 hp - Answered by a verified Marine Mechanic We use cookies to give you the best possible experience on our website. Mercury offers a full line of motors with varying degrees of power output. As one of the Midwest's largest authorized Yamaha dealers, we have the experienced staff and the Yamaha outboard motors selection to help you find the right outboard for your needs. Most 9.9 outboards are just 15 hp that have been set to put out only 9.9 hp to meet the needs of boaters on waters restricted to 10 hp or less. Which is faster 15 hp mercury 2 stroke or 15 hp mercury 4 stroke? This question gets asked all the time and the answer is always the same. This will slow the acceleration of the motor but the overall top speed will increase. Generally most of the 15 hp engines use the same block as their 9.9, 9.8 or 10 hp whichever. However, most 15 hp engines will not make the boat go faster as the top hull … Post a question at Ask-A-Member at aomci.org and see if you can raise a response about who that is. I would have no problems hanging a 15 hp outboard on it. Answer. At just 111 pounds, it’s suitable for lightweight craft such as aluminum fishing boats, tenders and inflatables. By continuing to use this site you consent to the use of cookies on your device as described in our cookie policy unless you have disabled them. In short, blueprinting is one way how to make … The Tohatsu 15 HP outboard motor was recently named as top choice in Boating Magazine's Buyer Guide for 15hp class! i have a 1975 15 hp johnson and i want to make it go faster!!!!! I have a 15 hp outboard motor on my boat, its way too slow as is, let alone having 5 people on board. Portable 15 hp. my boat is 12ft and lite as it can be with a 15 hp on it . Nothing on the water today is faster or more proven than the OptiMax Pro XS. Re: how can i make my 1975 2 stroke 15 hp johnson go faster Just thinking, there is a guy in the Florida Chapter of the Antique Outboard Club that has a 15 that just flat-out RUNS. You may also visit the Boat Motor Manuals section of our site to obtain a service manual. Re: How to make a 25 hp mercury outboard faster. You can change props or have them modified to a smaller pitch,you just run slower but get more push. Boating Magazine It is more economical for the outboard motor company to manufacture one engine for both the under 10 HP and the above 10 HP market and just make a different carburetor, idle mechanism and air supply to make the difference between 9.9 HP and 15 HP. On high-performance boats, the process has delivered up to 10 mph increases in top speed. If you are looking to get the top speed out of your motor, select a propeller that has a higher pitch. What kind of boat has a minimum HP rating?