Just bought a 13hp Beavertail with the honda gx390 on it. I own a 1648mv. I know it won't be the quickest boat, but I want to get everything I can get out of this longtail. Any tips on upgraded props or engine mods? Any advice would be great.

go to the kart forums. There are lots of mods out there for that motor.

Mark F. Cheney

I'll let you know soon. I'm in the process of rebuilding my 13 hp GX 390 Mud Buddy lt.

YES, You can bump your 13 hp to 30-40HP with the right mods--IF MONEY'S NO OBJECT!

But, since I like to eat and need to pay bills on time, I just ordered a Stage One Hop Up kit from NR Racing. The Order included a "mudmotor header pipe and screw on muffler" that are directed out the back, parallel to the shaft. With a replacement crankcase seal and a couple of other incidentals, I'm in at just over $100 plus postage.

(AGK--Affordable Go Karts --also offers bolt on performance kits and great web site tutorials on how to get the most out of your engine. I just couldn't get them to answer the phone when I had some questions, so I called and went with NR Racing. Think I got a better deal, anyway.

My ace mechanic, a guru who will remain anonymous for now and be known only as "Mystery Man" is helping me do the mods. He's also helping me replace the lower seals and bearings on the shaft. This is quite an amazing project I was in no way qualified to attempt! I am in awe of his knowledge and skills.

Not sure what size/pitch the prop is, but he says it's got plenty of cup and in good shape. I'll be running it on a 14 x 42 jon boat that has a homemade casting deck and the middle seat removed for hunting.

As I see it, the benefits are it's the least expensive way to keep the lighter weight of a PAID FOR 13 hp and, if I'm lucky maybe approach the power of an 16-18 hp when all's said and done. Will I be hauling ass anywhere? No, but maybe it'll be at a little faster pace and give me a little more power when I get myself in places I might shouldn't be. Good Luck with your project.

Hey thanks, yeah hauling ass just ain't the goal. I just wanna be moving a bit quicker but don't wanna buy a 23. I'll have to check out those kits for sure.

If money is of concern, Then concentrate your efforts on your carb and exhaust. Affordable go kats has an excellent tutorial on tuning your carb to your altitude. Combining their tuning of the carb with an improvement in both the air filter and the exhaust is relatively inexpensive.

Industrial motors such as yours is are designed with the idea of keeping the total package as small as possible, cubically. This is not the best way to get the freest breathing of fuel and exhaust. Good luck!

Mark F. Cheney

I had hopped up a 13hp with AGK and dismantled the governor....I believe the billet crank is a must for these goodies as mine only lasted about 15-20 minutes until it locked up tight. Needless to say I just pourchased a 16hp for my homemade surface drive