upgrading a 50 HP merc.

[cheesehead]

I just found out that Mercury's 50 and 60 HP engines have the same engine displacment. After talking with the merc rep he said that there is something that can be done to upgrade the 50 into the 60. But due to legal issues he wouldn't divulge what the difference is between them.

I'm looking to find out what I can do to get 60 HP out of my '03 50 hp 2 stroke. I occasionally pull a skier and tubes and a 20% increas in power would really help getting things started.

My boat is rated for 60 HP so I wouldn't be over powering my hull I'm just trying to avoid buying a new motor that is the same as one I already have if I can just swap out a few parts to get what I need.

Have any clues or places wher I could go to find out what I want?

[Can'tFishEnuf]

I would be interested in this also. I have an '04 50 4-stroke Yamaha. Since Merc and Yamaha use the same block I would think I could do this also. All the specs appear to be the same between the 50 and 60. Anybody know anything about this?

[DTro]

I always thought it was just bigger carbs.

[Guest]

I would guess the 60 probably *breathes* a little better than the 50. Smaller jets in the carb of the 5o might be part of it. Its not impossible the 50 is just a down tuned 60. It should be easy to research the carbs.. just call a shop and ask if they have the same carbs, and call for parts and see what there are for jets in the carbs. If the motor is somehow tuned down and you put bigger jets in the carb, odds are you are going to have problems with too much fuel. Someone out there will tell you. Make some calls.

[jigeye]

It might be easier and cheaper to just try changing your prop when you are pulling tubes and skiers. A prop can make a big difference. I had a 60hp Mariner and a buddy of mine had a 50hp Merc on the same boats. We were dead even on hole shot and top end. I ran a 13 pitch when pulling tubes/skiers and trolling and a 15 pitch for everthing else. Keep an eye on your rpm's at WOT with the smaller pitch prop and don't go over what your manual suggests.

[PerchJerker]

It has to do with the carbs and jetting. DON'T DO IT. I know 2 or 3 people and have heard of others that tried to tweak more h.p. out of their motors this way. The only thing it got them was motors that didn't run as good as they did before the "upgrade" - rough at WOT and would barely idle at trolling speeds. None of them thought they had more power or more speed. If you want a bigger motor, you're better off buying one than trying to make one, unless you love to tinker around with stuff like this on your own.

[Valv]

Listen to PJ, the amount of speed gained is not even possible to measure, the hassles of incorrect carburation and damages to motor are countless.

[Can'tFishEnuf]

Yea, it doesn't sound like a good idea. I'm sure it would void my warranty too. Oh well, the 50 gets me around pretty well.