Top speed of 7mph...oh and how do you adjust the idle?

TheForceGuru

Recruit
Joined
Sep 3, 2017
Messages
2
Hello everyone!
I recently acquired an old "Ouachita 15' bass boat with a mid 80's 50hp Mercury 2-stroke. It fires right up and runs great but the idle is set ridiculously high. I can't seem to figure out how to turn it down so I'm just been choking it enough to bring the RPM's down, then put it in gear, then turn off the choke. It will then cruise at 5mph at the lowest throttle setting. Once you start throttling up the front of the boat comes way up and it starts throwing a wake like I'm doing 30mph, but it has a top speed of 7mph! In fact about a 1/4 throttle does the same speed as full throttle, the only difference is of course the RPM's, the front end is out of the water and I'm throwing a huge wake. The prop has a pitch of 12" but from what I've read it looks like it's supposed to have a 15" pitch on the prop. My question is whether or not the prop would make that huge of a difference or am I facing another underlying issue? Thanks for any help anyone can provide!
 

RCO

Petty Officer 1st Class
Joined
Jun 15, 2016
Messages
350
The prop you have won't make that dramatic of a difference. If anything it should plane out faster with a 12 pitch. My guess is that you aren't firing on all cylinders, and the previous owner adjusted the idle timing to compensate. Check your compression first, then start looking for ignition on all cylinders, and lastly fuel delivery. Once you are sure everything is working the way it is supposed to, adjust idle back to specs.
 
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