3.0 Merc. problems

birdy3897

Petty Officer 2nd Class
Joined
Sep 10, 2005
Messages
126
I have a 1984 3.0L mercruiser which seems to be having carb issues. It can be hard to start initially and trys to die out at about 3k when on the water. Once it gets past 3k it will rev out over 5k. Also, after it is running and you shut it down for say an hour, it starts very hard. If you start it fairly soon after you shut it down it starts right up?? The motor is mechanically sound, I'm just not the best with carbs. I think the carb may possibly need a rebuild kit??? It almost sounds like it is flooding after I run it and it sets. Can't explain the bog at 3k rpm though??? What do any of you think????? Any help would be appreciated!
 

dubs283

Vice Admiral
Joined
Jul 27, 2005
Messages
5,333
Re: 3.0 Merc. problems

when was your last complete tune-up?? plugs, wires, cap, rotor, points, fuel filters, set dwell, set timing, adjust idle, test drive
 

birdy3897

Petty Officer 2nd Class
Joined
Sep 10, 2005
Messages
126
Re: 3.0 Merc. problems

The last tuneup was last fall. The thing is that the motor runs great and idles great once you get it started and only has problems restarting after it has been shut down for awhile and when I get to the middle range of the RPMs. My thought is that when it sits after running it is flooding, making it hard to start back up, and it smells like it also. I'm sure the carb hasn't been rebuilt since 1984, but I don't want to waste time and money if it is something else??
Also, once it is starting and you shut it down, it will start right up very quickly if you try it just a couple minutes after shutting it down.
 

birdy3897

Petty Officer 2nd Class
Joined
Sep 10, 2005
Messages
126
Re: 3.0 Merc. problems

One thing that I don't think is correct is my fuel line is rubber fuel line. Could this be causing the problems I am having??? It looks like it was once steel?
 

michaeli84

Petty Officer 3rd Class
Joined
May 26, 2009
Messages
80
Re: 3.0 Merc. problems

Check your choke i had the same problem and it was the choke on the carb was staying shut. There is also a check valve in the feul line at the top of the tank you might want to clean it out.
 
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