76 OMC wont rev up in gear < need help >

ok i have an ankorcraft open bow 16ft. with an inline 4cy gm engine and a stringer outdrive, that says 120 on the top cover. what we did was since my 120's waterpump wasn't workin we swapped in my brother OMC < approx 79> 800 series , upper gear case w/waterpump, now the waterpump is working fine and the boat runs well in neutral, when in gear however wont go over 2100 rpms, < should note that in neutral revs upto 4k easily ,wont push it further> boat is only doin about 17mph and i'm pretty sure a 120hp in a 16ft should do better. my Question is could the different uppergear case be preventing me from goin? faster

If not and should work fine then any other helpful hints will surely be appreciated. I have changed the points, plugs ,fuel filter , have ran 2 loads of seafoam thru it now , and have taken off the Carb to clean it some , since boat sat for 2 seasons.

NB

Re: 76 OMC wont rev up in gear < need help >

lots of views no clues


well it was worth a try.

Re: 76 OMC wont rev up in gear < need help >

Northboater said:

my Question is could the different uppergear case be preventing me from goin? faster

Click to expand...

yep - it has a different gear ratio inside. It's like trying to drive a car around in 5th gear now.
just spend the $14 on an impeller for yours.

Re: 76 OMC wont rev up in gear < need help >

thank you i do appreciate it.