1995 Merc. 150hp 2.0 / bog and stall

K

kingfish62

Seaman Apprentice
Joined
Jun 6, 2007
Messages
42
I have a 1995 Mercury 150 hp Carbed 2.0 ltr on the back of an 18 ft US Marine Quantum Bass Boat. The engine cranks easy and idles smooth at first. I can run out at any RPM and all is well and seems to be running normal. The problem is once the engine is good and warm (I.E. 15 to 20 minutes or more running time) when I come down to idle speed the engine wants to bog and then stall. The bog almost feels like the prop is dragging bottom. If caught in time and given the throttle the engine will head back up in rpm and if not it will stall and then wants to be hard to restart. Any idea on where to start would be appreciated. Thanks in advance.
 
jerryjerry05

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,927
Re: 1995 Merc. 150hp 2.0 / bog and stall

Profile first. Ethanol is messing with a lot of motors.
Possible the tank vent is clogged.The fuel pump diaphram gone bad.The pump rebuild it.Check the hoses.Soft or too hard.E delaminates the inside of older hoses.
Check the carbs for gunk.J
 
Faztbullet

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,618
Re: 1995 Merc. 150hp 2.0 / bog and stall

Sounds like some varnish in carb. Add some Quickleen to fuel and retest, if it does not improve...open all 6 idle mixture screw 1/8 turn CCW and check the thermal air valve on starboard head. The thermal air valve makes it run richer when cold.
 
K

kingfish62

Seaman Apprentice
Joined
Jun 6, 2007
Messages
42
Re: 1995 Merc. 150hp 2.0 / bog and stall

Thanks Jerry Jerry and Fatzbullet, I will look into the items that you both have suggested. I have been running a stretch of 12 hr night shifts here these past couple of days and sleeping days so haven't had a chance to tinker witht the boat. I will let you both know what I coe up with.
 
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