Non Stop Mercury 150 V6 2.5L Problems

[fbaxter3471]

Ive been on here a few times already with fuel problems, water pump problems, ect.... Now my mercury is acting the opposite as it ever has. I had gas leaking from the carbs a week ago and took to a mechanic and had the carbs rebuilt and a new control put on, because I had broke the other. Well this saturday I took out and about 15 minutes of WOT my primer bulb sucks in AGAIN, throttled down and it primed back up. I have replaced the bulb, fuel line to the motor, water separator, and the tank vent. The only thing I havent replaced is the fuel line from the tank to the separator. Also when picked up fuel sending unit had rusted off of tank and tank was completely full of water but siphoned tank so I think I might be getting trash, any other suggestions. Next problem is this motor must be a hot running motor according to the manual the overheat alarm doesnt sound until 240 and deactivates at 210. Well this motor has always ran at 125 in neutral, 145 slow speed and 180 WOT, and never had a strong pee flow, well now all the sudden the pee flow is strong and it is running hotter on idle than when throttled up, and smoke and minimal water is coming out of exhuast when water use to stream heavy out of the exhuast. Also on saturday my control got stuck and when I would crank up it would be full throttle even in neutral, and I adjusted my idle screw and not it seems to be fine. Any suggestions helpful I have had a roller coaster with this motor.

 

[CharlieB]

Re: Non Stop Mercury 150 V6 2.5L Problems

about 15 minutes of WOT my primer bulb sucks in AGAIN, throttled down and it primed back up. I have replaced the bulb, fuel line to the motor, water separator, and the tank vent. The only thing I havent replaced is the fuel line from the tank to the separator.

This should be obvious, either the tank pick-up tube, fitting, or hose, is restricting full fuel flow, the fuel pump is pulling a vacuum and collapsing the bulb.

Change the hose, pull the fitting and dip-tube and look.

 

[fbaxter3471]

Re: Non Stop Mercury 150 V6 2.5L Problems

If there is trash in the tank, how do I get it out, I have already siphoned this tank out once, its a 70 gallon

 

[j_martin]

Re: Non Stop Mercury 150 V6 2.5L Problems

If there is trash in the tank, how do I get it out, I have already siphoned this tank out once, its a 70 gallon

Normally, we don't fill up boat gas tanks with water, leaves, and seaweed or whatever. Just siphoning the easy water out won't get all the debris out. How you clean it depends on a lot of things, but clean it you must if you don't want to lean out the engine and burn down the power head. Then you can learn some real mechanics, as in rebuilding the power head.

The overheating problem is pretty obvious. The water pump failed. BTW, about 15 seconds running without water is all it takes to wipe out this one. They also fail from sitting, so if you didn't replace it right off when you got it you got a few minutes of free running on the old one. I consider the water pump maintenance to be an annual item.

Don't blame this fine motor for your problems. So far, everything in your litany is anthropogenic. (man caused)

 

[fbaxter3471]

Re: Non Stop Mercury 150 V6 2.5L Problems

This motor just had a full annual service about a month ago which included, new water pump, changed lower unit oil, poppet valve, t-stats, plugs. As for the trash in the tank, when picked up the fuel snding unit had rusted off and some peices of rust fell in the tank im sure, after I siphoned the tank out I stuck a shop vac with a long hose to try to get anything left, but being a 70 gallon tank and not being able to see I must go off hopes. Also note that this weekend I was scalloping and ran through large amounts of seaweed even once having to stop to lift motor. Is there a way that when the bulb collapses to keep what ever trash is on the pick up and pull it out of the tank and clean.