merc 120 too fast at creeper speed

melvind1

Cadet
Joined
Aug 5, 2013
Messages
10
Just got a see sprite with a mercuiser 120 runs great and boat is in tip top shape. Only problem is that at docking speeds it just doesn't go slow enough and I have to put it in and out of forward and reverse to control it and it really slams into gear then moves pretty fast. Any tips on how to adjust the idle down...it does this at the beginning and end of voyages.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: merc 120 too fast at creeper speed

Idle speed should be 650-700 rpm,in forward gear, in the water. If it's higher than that, just turn the idle speed screw, just like you would on a carburetorred car engine....

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Chris.....
 

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melvind1

Cadet
Joined
Aug 5, 2013
Messages
10
Re: merc 120 too fast at creeper speed

Thank you.... I am guessing very small turns to the left to reduce speed and to the right to increase speed.
 

Bondo

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Staff member
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Apr 17, 2002
Messages
71,348
Re: merc 120 too fast at creeper speed

Just got a see sprite with a mercuiser 120 runs great and boat is in tip top shape. Only problem is that at docking speeds it just doesn't go slow enough and I have to put it in and out of forward and reverse to control it and it really slams into gear then moves pretty fast. Any tips on how to adjust the idle down...it does this at the beginning and end of voyages.

Ayuh,..... Welcome Aboard,..... What are the idle rpms,..??

The idle is adjusted at the carb's idle adjustin' screw,...
 

melvind1

Cadet
Joined
Aug 5, 2013
Messages
10
Re: merc 120 too fast at creeper speed

I will double check the idle speed today. Any other items that could cause that..ie... Cable adjustments etc? Thanks very much for the responses. And yes,I realize I misspelled sea in my original post....
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: merc 120 too fast at creeper speed

If the cable is out of adjustment, just remove the nut holding the brass (sometimes plastic :facepalm:) barrel on the bracket and wind it in or out so it doesn't pull the throttle open.... Do the idle speed adjustment with the cable disconnected, then adjust the cable and refit.... Once you see it you'll understand... ;)

Chris......
BTW, don't care what boat your engine is in, the most useful information you can provide is the engine serial number.
 

melvind1

Cadet
Joined
Aug 5, 2013
Messages
10
Re: merc 120 too fast at creeper speed

Thanks again.rain yesterday so didn't make it to the marina.
 

bonzoscott

Senior Chief Petty Officer
Joined
Jul 26, 2008
Messages
745
Re: merc 120 too fast at creeper speed

If you're new to boating, and your idle is normal, it does sometimes take a little shifting and maneuvering when docking.
 
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