Mercury 40/28 question

[Fatjake]

Long time looker, first post here

I have a 2003 mercury, longshaft , 2 cylinder, 1 carb, 40/28
that I bought not knowing WTF I was doing( I assume this motor has been converted to a jet as the title says 40hp and the long shaft)
I mounted it up on a 1652 blazer

It runs 23-24 with just me in the boat... But it leaves something to be desired
I live south of St. Louis and I know there is a wizard on these motors that lives south of me

Was wondering what I could do to make it run a little better and what kind of gains I should expect?
Or is it even worth doing to this particular motor

Thanks

 

[Lil' Blue Rude]

I'm all for hot rodding on these small outboard jets but I think this is one motors that will just be pretty limited from the get go.

Not saying it can't be modded there's just better motors to star with. The reason I say your motor limited is because the head can't be removed to shave it to raise compression, single carb( that could be changed with some cutting and 60hp merc intake) and these motor run reed plates using flower petal reeds instead of the "V" block reed cages like most other motors use.
Not saying the motor can't be modded but it will be harder and cost more to build up that motor vs a Johnson, evinrude, or Yamaha of that size.

But if you do want to mod it I've heard the 60/40 mercs respond well to porting the reed cages and putting fiber reeds in them. You can probably have a exhaust tuner built for it. You can mod a 60 intake so you can use 2 carbs, probably be best to find 2 30hp carbs to not flood the motor. Then there's porting. If you port it then you might be able to use 2 40hp carb on the custom intake.

As far as setup you want the motor as high as possible without cavitating. I normally try to have to bottom of the boat even with the pin that holds the grates in the front of the shoe. keep the impeller sharp and smooth out the inside of the jet pump.