1988 Mercury 90 HP Oil Injected (Too Rich/Too lean?)

VaBeach1234

Cadet
Joined
Jul 11, 2002
Messages
22
Hey guys, you have no idea how much I've learned from this site. I'm new to boating, I bought my first boat about 2 weeks ago. I took her out for a test run and she purred like a kitten at the dock when we first started it up. When I punch it after idleing/no wake speed for about 5 minutes she tended to stall/lag around 3,000 RPM for a second or two and then launches from 3,000 to 5,000 extremely quick. After that, idleing is a little rough, in fact she cut off when I put it in reverse to slow down when I returned to the dock, and she was smoking a little.<br /><br />I started playing around with the adjustment screws on the carbs and noticed that the shop/dealer that I bought it from had the top cylinder turned out 4 times, the middle cylinder turnied out 3, and the bottom cylinder turned out 2. From what I've read, this should be running lean, right? But the cylinders seem to be loading up on me. Am I doing something wrong? Do I need to turn the screws out even more?!? All the books/post I've read tell me to start out with the screws 1 1/4 out from slightly seated. Is 4 turns too much or is this just the nature of the beast. Has anyone heard of someone having to turn these screws out that far? <br /><br />Thanks.<br /><br />1988 Glassmaster S-196<br />1988 Mercury 90 HP Oil Injected<br /><br />"I got to start wishin', I got to go fishin', I'm down to rock bottom again." J.B.
 

Trent

Captain
Joined
Nov 17, 2001
Messages
3,333
Re: 1988 Mercury 90 HP Oil Injected (Too Rich/Too lean?)

Time to re-adjust. Engine must be warmed up, In the water and in gear to adjust correctly. 1.25 turns is just a starting point. But 4 turns is way to much...
 

VaBeach1234

Cadet
Joined
Jul 11, 2002
Messages
22
Re: 1988 Mercury 90 HP Oil Injected (Too Rich/Too lean?)

Thanks Trent. I thought 4 turns was a bit excessive. I'll give it a try today. Thanks again.
 
Top