Mercury 650 intermittent bog problem

Hammssammich

Cadet
Joined
Mar 9, 2016
Messages
14
I'll try to include as much info as I can.
I have a 1969 Merc 650 4cyl. With the thunderbolt ignition. Everything appears to be original. The motor starts and runs great most of the time. When on the water if I kill the motor and try to restart it will start but bog down when throttling up. It doesn't do it every time. I've checked the fuel hose and bulb, the vent on the tank, the filter in the tank as well as on the motor. The carbs were cleaned and adjusted. If I let it idle for a minute or so it clears up.
Where should I start?
Thanks in advance!
 

enginepower

Petty Officer 1st Class
Joined
Jul 5, 2014
Messages
260
My jet ski would do this. It was running too rich at idle plus it was getting too much oil. After idling about a minute, it would bog and smoke like a freight train on take off. After a few seconds of hard throttling, it would clear out. Are you running the proper oil/gas mix for your motor? Mixture could be too rich or float needles leaking or set too high.
 

Hammssammich

Cadet
Joined
Mar 9, 2016
Messages
14
Hmm, that would explain the intermittent nature. I run 50/1 as I believe is recommended. Always the Quiksilver brand oil. I'd be a little nervous to lean it out much tho.
 

Hammssammich

Cadet
Joined
Mar 9, 2016
Messages
14
Also I should mention if I let it die I need to choke the motor to get it to start again when warm. If I put it in gear and it starts to bog I can usually get it back to neutral before it dies out.
 
Last edited:

Hammssammich

Cadet
Joined
Mar 9, 2016
Messages
14
Okay, pulled plugs - all relatively new with some oil deposits. Checked compression - #1 130lb #2 135lb #3 130lb #4 130lb - Good spark on all. I was surprised the plug wires look original. Fuel lines look good enough but tough to tell if there intact inside. Am I looking at a carb issue?
 
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