A Mariner boggs down when trying to troll

al9981

Seaman Apprentice
Joined
May 2, 2009
Messages
35
I read and searched a lot about motors bogging down at low speed but my symptom is a little different.
I have a 1988 75Hp Mariner on a 1969 19ft Starcraft Holiday. The boat was setting for seven years and last year i replaced spark plugs, fuel lines, filter, rebuild fuel pump, water pump and carburetors.
It will start right up on the launch. I can idle, troll, low speed and high speed it s great as brand new motor. My high rpm is around 5500 rpm at 35-38mph.
I stop to fish for an hr or two. Before I start the motor, I will pump the bulb couple time, and let it warm up before I want to move somewhere else. Idle sounds really rough. If I try to troll or low speed, it will bog down and shut off. But If I give it some throttle, it will not bog down or shut off. After driving around for few minutes with some throttle, it will allow me to go down to trolling without shutting off on me.
Thanks in advance for any help.
 

al9981

Seaman Apprentice
Joined
May 2, 2009
Messages
35
Re: A Mariner boggs down when trying to troll

Any help how I can fix this problem. I know there are alot of experts in here. One thing I forgot to mention, when I rebuild the carburetors I did not adjust the idle screw just because it idles fine.
I dont have any fuel leakage, the bulb does not get soft either.
 
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