Just sold my 20 hp Longtail that I ran on a 1642 custom flat
Thinking about but a 24 hp Longtail I just found but wondering about speeds. My 20 hp did 19-20 MPhil with em and 17-18 with me and one person. How big of a difference am I looking at in speed?

I will venture to say, all things being the same, you might obtain an additional 2-3 mph more. A variable there might be the prop size, you should be able to spin a 9x6 but it will be trial and error. Is that a Honda 24? My friend had one that was a lemon and others had trouble with their units but otherwise a solid powerplant. You can certainly run a 25/ 27 Kohler LT on that 1642. In mud and weeds you will have more torque and push with that 24. The 23 Briggs is a good compromise and that usually comes with recoil start and electric, and that motor can be modded up. As others on this forum have stated, I will also recommend a BackH20 motor over the other mfg.'s.

Yes it is the honda. I'm only working with 1500 right now so I'm limited but may wait and see what else I can find

That 24 is a fine motor. Havent met one yet that doesnt have more than 1000 hours. We ran one for 15+ years, its got another 3 on it since we sold it. Had to redo the shaft and seals/bearings once, and it's had a few props, but the motor is still going. Id recommend that honda without hesitation.

You might get another mph or two, but you'll def get more umph at lower rpms.

Im with Russ - probably wont pick up much speed but be able to carry a load a little better and be better at digging out of stuff. I picked up an 02 mblt with the 24 a couple years ago and have been real happy with it. Woodiebuster on here also has one.