Mercury 150 low speed problem

kirmy22

Seaman
Joined
Mar 8, 2010
Messages
73
I have a 1983 mercury 150, Ive had it for about three years and it has never ran right. I have posted on here before but never figured out what was wrong when i would give it throttle it would bog down really bad, I could keep messin with it and it would finally take off and run perfect untill I slowed down and then the same thing over again, thought it was the stator I replaced it and the same thing. Has good compression carbs rebuilt I drilled my prop so the motor would wind up quicker and that fixed that part. It idles fine but if you try to go slow it still has sort of a miss and the engine runs rough still kinda boggy, but if you give it some throttle it smoothes out and gets on plane quick and runs great but if you slow down it just doesnt run smooth. If I rev it up in neutrol it doesnt wind up fast like it should, I am out of ideas, anyone else have any guesses. Has new plugs put seafoam in the tank hoping that will help after time.
 

Iceman66

Petty Officer 2nd Class
Joined
Jun 30, 2008
Messages
199
Re: Mercury 150 low speed problem

Have you checked fuel pump, could be a small leak there in the diaphgram.
 

335i101

Cadet
Joined
Jul 7, 2013
Messages
18
Re: Mercury 150 low speed problem

I have the same problem with my 91 150.

Replaced the stator, now replacing impeller and thermostats....
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,148
Re: Mercury 150 low speed problem

Are the carb idle mixture settings adjustable? If so, they may be mis-adjusted.
 

kirmy22

Seaman
Joined
Mar 8, 2010
Messages
73
Re: Mercury 150 low speed problem

They are not adjusable, and I rebuilt the fuel pump back when I first started to fix the problem along with cleaning the carbs did a link and synk I think I got it right it has no miss whatsoever once your above half throttle. Thanks for the replies so far.
 

335i101

Cadet
Joined
Jul 7, 2013
Messages
18
Re: Mercury 150 low speed problem

They are not adjusable, and I rebuilt the fuel pump back when I first started to fix the problem along with cleaning the carbs did a link and synk I think I got it right it has no miss whatsoever once your above half throttle. Thanks for the replies so far.


Kirmy-(not trying to thread jack-if you want me to "not comment" let me know, but it seems like we have the same problems)

I had my idle adjusted by a dealer last week, it starts and idles better....but still dies out as described. I pulled out impeller and thermostat....one of the impeller gaskets was torn....waiting on parts now...
 
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