1981 Merc Gnat...progress but won't rev up?

I was born in 79' and had some little toy boat with a little plastic merc this era and it reminds me of it, so I want it to work right so badly. I just know my 1939 12 ft. magnesium row boat will be an absolute hot rod with it funning at WOT!!!
Anyway, I changed the plugs, made 50:1 mix with merc oil. Cleaned out the carb, which originally was leaking gas profusely, so I readjusted the float, by eye. It now idles somewhat smoothe and consistant, however, I have not succeeded in getting it to rev. It revs highest at the start position on the throttle and I can't seem to get it to rev past that. I think it's getting way too rich, but I'll second guess myself and sometimes think it's starving up there, it will sound slightly different when gassed but if anything just start breaking up. it's happiest at idle and start position...I want RPM's!!!!!
Would so much appreciate the quick fix!!!!!!...I may make a video post it on Youtube and post a link here!...Paul, I'm sure you know what I need, you seem to know the damb gnat very well!! I've read all posts on the gnat and I now feel justified in placing my own post , maybe someone will relate in the future!

Re: 1981 Merc Gnat...progress but won't rev up?

Could I hurt anything by running some seafoam through it?
Maybe she just needs to clear her throat?
Does a carb rebuild kit make sense, or is such a thing still available for this piece?...are they expensive?

Re: 1981 Merc Gnat...progress but won't rev up?

I don't know what ignition is on that gnat, if it is a points then improper gap can idle and lightly rev but will not fully rev.

Need more info on the engine to look it up, need numbers.

Re: 1981 Merc Gnat...progress but won't rev up?

Has 2 coil packs, one per cylindar.
Serial # 5762536
My friend and I just took apart carb, bent float flap back up so needle sets later and also were messing with the timing of the engine, without a light, ...for a moment it seemed to be running up high, it would ba ba bba ba bba bbbbaaaaaaaaaaaaaa, stayed there revving nice for a moment and so we drove it to the lake where she would just bog...actually performed worse than last time in that it would go to stall when given the goose, back to running highest at start. I need to measure the float flap gap and see if that was it when I know it is in the right place...Laddies shot me a more detailed description of how to measure and I'll be attacking this tomorrow!
Thank You! My dad is claimin I need a 9.9 cause they're really like 15 horse and the 4 is all 4 at best......thank god for me getting this thing for free, can't beat that with a oar. I just want it to scream!! Haha
I think I'm getting closer.

Re: 1981 Merc Gnat...progress but won't rev up?

2 possibilities come to mind

First, carb cleanliness and adjustment and fuel pump supply flow
too lean an idle mixture, idles fine at home, bogs once in the water, adjust idle in gear in the water to best idle speed

2nd, marginal crank seals
contains crankcase pressures at low speeds low loads but fail/bleed off pressures with application of much throttle under load

I'm hoping that it is just the carb, once underway try pumping the primer bulb to see if it improves

X'd fingers