I've got a 1448 G3 with a 21hp MB LT and its running about 10-12 mph with just me in it. It seems like I should be getting more out of it than that, just wanted to know what yall thought. I just put a new prop on so that shouldn't be the problem.

Ive heard sometimes youve got to break in a new prop. Or it may be wrong size. Or wrong transom height. Also it could be weight not distributed right. Theres alot of thangs to check. Cav. Plate. RPMs. Dents on hull

The prop should be broken in, and the hull is in good shape. My main concern is rpms. I don't know how to check that or what it should be for a 21 HP. Do you think my rig is underperforming or are my expectations to high for this motor?

What size prop.did u buy?

I don't remember, I called the dealer and told them what I had and they told me what I needed but I don't remember, id Have to measure.

If your ever going to get the most out of your rig your going to have to get a tach on the MM,,,,that will tell you what u need to do,,,if your rpms are good then it the load/hull,or not enough HP, if the rpms are off then its the prop

What's a good tach to get and where?

Tinytach, order it from Tinytach.

You should be able to buy a tinytach over the counter at any lawn motor shop or small motor shop.

If you order direct, you have a better chance of getting one with a fresh battery. You have no idea how long the one at the lawnmower shop has been sitting on the shelf.

I'm running a 1548 G-3 with a 23 GDLT top speed with a light load is 18.2 Mph for me .

Thanks just checked them out. Ordering one tonight.

Getting a new go devil 16 hp longtail sunday i will putting on my 14x36 jon boat does anybody have a set up like this, would like to know how it runs ,can't wait to get in the marsh