Need Help on Merc 120

brunowren

Seaman
Joined
May 30, 2005
Messages
60
Ok Took the boat out for the first time today! (1975 Tropicana 18' trihull w/ merc 120 sterndrive)<br /><br />Starts fine put it Reverse back away from the dock ... Go forward on idle... Dies after a few min... <br />All day Starts .. Give it gas Dies.. sometimes it would run at about 6 mph for about 2 min then die<br /><br />could hammer the throttle would pull up on plane and die in 10 seconds<br /><br />When in netural I start playing with the Lever behind the Throttle the goes up and forward(I was told it was the "fast idle choke" I could get to RPM 3-4000 at idle <br /><br />But would let idle come down to where is would shift and would run about 10-15 second and die! <br /><br />Then it even got to where it was hard to idle...<br />But it just kept on starting up....<br /><br />Previous owner told me he got the boat had bad gas.. he got it all out ..<br />Put in new Fuel pump and line (from tank to pump)<br />But it would still dies a WOT! <br />Said it would go all day at 3/4 ! Yea right<br /><br />The throttle seems strange to me! I have to push it almost all the way forward to where it is at a 90 deg angle(fully pointed forward) before it engages gear <br /><br /><br />Please help ! We plan on going out next weekend <br /><br />PS ! The damn thing runs fine in the Driveway :rolleyes:
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Need Help on Merc 120

PS ! The damn thing runs fine in the Driveway
Running in the driveway with no load isn't a problem for any engine, no matter how bad it runs.<br />I would guess that with previous bad fuel problems, you are due for a carb rebuild to clean out all the passages. Then do a complete tuneup, points, condenser, cap, rotor, sparkplugs, setting the dwell, adjusting the timing, checking advance timing, and adjusting the carb mixture.<br />Bet it runs fine after that.
 

jeff13601

Chief Petty Officer
Joined
Apr 30, 2005
Messages
593
Re: Need Help on Merc 120

I would definately say Don has it right. You can get everything but the carb kit for 30 bucks. You may luck out and might not need a carb kit
 
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