I have a lowe stinger 17'6" with a 50hp mercury 2 stroke, top speed from the factory with just me in it is 32mph and actually a little faster with my wife and kids in it maybe 34ish. The boat comes on plane really quick so it got me to wondering, could I put a different pitch prop and gain a little on the top end? What about a jack plate? I know it's not a speed boat but i typically fish PK and I need any extra speed I can get!

You could play with prop pitch but I would not invest in a jack plate on that rig. I'm a little puzzled as to how you can load the wife and kids and get more out of it. Maybe add some neighbor's too?? Lol. Traditionally, if you have great hole shot now, you may be able to go up a pitch, but you'll lose a little hole shot. Maybe.... I am not familiar with how these types of boats and motors in this HP range work. You can tinker a few thousand dollars looking a few more mph- don't ask me how I know this.

Good luck!

If your motor runs at the top end of the motor's operating curve at WOT it is propped correctly and to start changing that to get a couple more MPH is likely to risk motor damage over the long haul. The solution was and still is a boat with more motor if you want to go faster. It's a 50 HP motor and it is what it is.
A lot of the boat manufacturers under power their boats because keeping the advertised sale price down to improve sales. You find out later that you should have spent that extra couple of thousand. Maybe even several thousand and gotten the bigger boat.

I was hoping a re prop or a cheap manual jack plate might give me what I was looking for but I didn't want to spend a bunch of money to find out, I love the boat and great fuel economy I just wish I could get from A to B a little bit faster

Whatever you do, at most you might find 2-3 mph. Your prop is 90% of your performance, so you want to make sure you're operating at the top of the RPM range, and handles correctly.

Jack plate would be a waste of time and money.

Truth is, that's what that boat and that motor should be running, either trade up or just go fishing.

jack plate, different style prop, trim tabs, nosecone, weight distribution, engine mounting height, setback bracket
MORE HP!!! that little sucker would fly with the 80 its rated for
those all the things I can think of that will/wont get you a few more MPH, but the only one for sure is the last one[u][/u]

It sounds like I just need to shut up and go fishing thanks for the responses

You need to ask that at screamandfly powerboat ...... You can put reeds in it and jets, and maybe change the carbs out to BE ABLE TO TURN a bigger prop!

I do OMC motors, but over at screamandfly powerboat most of those guys do Mercury.

I've done a lot of tuning on these type of boats to gain more mph. Without spending a lot of money you can expect to gain 2 to 5mph realistically. One thing came to mind when you said you went faster with your family in the boat. This makes me think you motor may not be mounted to the correct hole height. You might wanna do a search on that. I gained 3mph gps on my 17ft Xpress by going up one mounting hole. A good Laser prop wouldn't hurt either. Goodluck

I hadn't thought about that, I just assumed it was because the weight was distributed more evenly causing it to have a little less drag but maybe it's a little bit of both, thanks for the suggestion

Pat has probably set up more boats than the rest of us combined, and I agree the best change you can get isn't going to be much and will cost a good bit. Corvettes don't operate at the cost/economy of an Accord.

You did not say how speed was determined. Pitot tube speedometer are inaccurate and can be affected by hull depth/angle. You didn't say what rpm you are getting and how that compares to the engine operating range info. You'll need to become obsessive about such things or pay a lot to someone who is (not very practical).

Is your prop aluminum or stainless? AL has thicker blades that flex more. This robs performance by %, so any improvement from stainless wold be small also. Having owned and set up small boats, I know all about limits & wishful thinking.

Your best gain (such as it is) is probably from a 3-point combo:

1. Learn your engine's rated rpm peak and prop to hit this.
2. Learn about proper engine height and set it correctly.
3. For 1 & 2, get the right pitch stainless prop.

There are no guarantees so you might get 0 mph, and if great, lucky to get 2 or 3.

Flippin-Out, and Pat are right, but if youre pegged out at 30, 3mph is a 10% increase. A 10% increase in top end with a little tweeking to me would be worth the time......but not too much money

Speed was measured with my Lowrance HDS and trimmed out wot is around 5500rpm so I really don't like running full throttle, cruising speed is around 22mph at 4000 or so

i have had alot of guys lately putting 4 and 6 inch setbacks on small boats like that and really gaining
some mph. of course the prop will change and or need to be worked.

i'm not super familiar with your boat. if it's a flat bottom or semi V then a plate will work.
if it's a deep V bottom, a jack plate will not help it at all.

just my experience

I believe you would call it a semi v Steve