2010 merc 20 hp, 4 stroke ... bummer.

Well, my motor is awesome really,very quiet, excellent on fuel, reliable ... I just thought it would be faster. Admitedly, the boat is heavily loaded. However, in a rough chop, even with just me ( 225lbs) in the boat, I can only get like 22 mph. I was hoping for better with the factory 10 pitch prop.

Bob.

Have you played with the tilt pin at all? What pitch prop is on there now?

What size rig are you pushing?

I have played with the trim position, too high and I start to cavate, too low and I plow, eetc. It is where it needs to be. My boat is a crestliner, 1648 modified V ( it is 15' 10" actually ). It has a wood floor, 2 - 27 M batteries, a bow and stern trolling motor and 2 seats. Also, I ahve a small tool box and hefty fishing tackle box on board. The naked boat is 275 pounds.

Bob.

Sounds about right considering your equipment.

Bob I have an 09 20 merc. It's very quite. Mine is about the same as urs. Very under powered. I was very dissapointed. I have a 1448 side console grizzly. I was getting 20mph. I removed the rear battery and got a 3 gallon tank and put .it under the console. Moved my anchor under the front floor. I now get 25 mph with me and a 9 year fully loaded. I had to take mine in for what I thought was a fuel pump or coil, they claim nothing was wrong but I can tell the carb was taken off so I think he rejetted it and/or tuned it in a little better. I get 27 with just me in it. And no gear what so ever.

I am running the 10 pitch prop. I also have a 9p aswell. The 9 is good with lord of weight, but it starts hitting the rev limiter. So u gotta back off the throttle. I keep it with me just in case.

Ever notice that when the four strokes dont perform everyone raves about how quiet they are and what amazing mileage they get?
Just having a little fun boys...........just a little fun! Don't get your knickers all twisted up!
Yes Sir.............Gotta love the good ol' EPA !

I would take a old two smoke and that beautiful sound over quite and mileage. Nothing better that the smell of pre-mix in the morning

I'll take quiet and low fuel usage any day over drowning in my own exhaust smoke! But I have a mild case of asthma so I am slightly biased.

All the people with "slow" 4 stroke motors...don't blame it on the weight until you've propped it "correctly" and offset the weight by removing some junk from the back of the boat. Like going to 3 gal tank instead of 6 or running one battery instead of two. All the guys I work with said mine would be a slug (4 stroke 25 Yamaha) but after setting it up right and propping it right, it's faster than the set up and propped 25 2 strok on the exact same boat.

I love the rumble of my two stroke 40hp Mercury (once a gear head.......). It is a little slower than my old 48hp two stroke Johnson though.

My 1652 Merc 200 20 hp 2 cycle, with me and all my gear runs about 24 mph. Empty with just me it will do about 26 mph so I would say your in the ballpark of where a 20 hp is going to run,

I think you are correct, I was just hoping it would run a little stronger ... I wanted to not have the weigth of a 25 4 stroke and I troll a lot so I did not want a 25 two stroke as I was worried about fouling of plugs and I get tired of the smoke trolling all day. Kinda wish I had a 25 two stroke now though.

Bob.

Just for comparison. I have a 48hp spl johnson motor (old 1988) but it runs good, my boat is 560 lbs empty, 16 ft fisher SV-2 . I only get 29 mph at full throttle (2 person and gear) but I am satisfied with that. Plus the 2-stroke smoke keeps the skeeters and other boaters away when I'm trolling. :twisted: And No its not quiet either, also mpg not great, 2 stroke oil kinda expensive but reliable so far, got the setup last year for $1400.
Tim

Sounds about right for a 1648. Mine does about 24 with a '03 25hp. It ran about 22 with a pair of '85 9.9s.

Make sure you are getting full throttle. I have a 2011 and after a while it started slowing down and found that the set screw on the wire carb linkage had slipped back some. Could still see a slight mark on the wire from the where the screw was originally tightened down. That does sound about right for a 1648 from everything I read about these motors in researching my purchase. The wide bottom really slows them down. Most don't believe me but my 1542 is running over 30 with mine where my 25 evinrude only pushed it 25-26. I guess I got lucky but I love this little motor. I believe you have the same boat as the Lowe and it is rated for 35hp tiller and 50hp console so it is under powered by quite a bit.

tnriverluver, good post, I will look into the throttle issue. I had a 1542 with a newer Merc 25 2 stroke that ran like a wild ape ... I think I was hittling in the low 30's with a stainless prop. The wider boat may be the issue.

Thanks,

Bob.

My 2-cents . . . my Lowe 1462 mod-V does 22mph on a Nissan 15HP 2-stroke, single person.

Link to my first wide open throttle run in my 1542 tracker. 32 Mph. Hopefully you can view this.

https://www.facebook.com/photo.php?v=395806340433796

22mph with that setup is right on the mark really. If you had an RPM reading you could adjust the prop size accordingly to get a little more out of it maybe but reality is with a 10 pitch prop, 2.15:1 gearcase and RPM max of 6250 your top theoretical speed is 24-25 mph. And that is with an 8-12% slip calculation which is a good slip ratio on most all props, especially stock aluminum.

Please do not think there is anything wrong with your motor because it is right on. And don't be led to believe you are going to ever hit the 30mph mark with that motor and your setup because physics will never allow it to happen.

Just think of it this way....In order for you to hit 30mph with a 10 pitch prop with a 2.15:1 gear case your motor would have to turn 7,650 RPM! That is with a 10% slip which is a very good hypothetical slip calculation. See what I am saying...it's not possible