HELP!!! 1981 Mariner 2 stroke 140hp keeps dying.

[Tony331980]

Hey yall,
​​​​ I am new to boats. My Mariner motor is all messed up. It was running good when I first got the boat. Then my 3rd trip out it would keep bogging out at full throttle, I would have to keep letting off when it started to seem to lose power then go back full throttle just to keep it going. Well the last time I had it out the motor totally cut off while at full throttle and would not start back up and had to get a tow in to the docks.
somebody told me I had dirty so I bought the Mercury Power Tune spray. I couldnt get it started to use the product so my neighbor used a little starter fluid and it started right up when I turned the key. It ran for about 10 minutes after I sprayed the power tune in the carbs with no throttle and I thought we were back to the water. Well after I emptied the bottle of power tune the motor shut off and now back to not even running for 30 seconds. Any ideas???
​​​​​​​Thanks in advance!!

 

[jimmbo]

Dirt/Varnish/Gum in the carbs/fuel system are the most likely culprit. Power Tune is a Combustion Chamber Cleaner for reducing Carbon Buildup behind the Rings. It is not a bad Carb Cleaner as well, if it able to get at the internal fuel passages. You can spray a pallet of the stuff into the carbs and the end result is a very clean carb throat, throttle plate, reed valves, rings and combustion chamber, but no difference when it come to dirt/gum/varnish in the fuel system. To properly clean the carbs, they have to come off, disassembled, including the removal of the disk plugs.

Check the fuel strainer in the fuel pump, the fuel pickup in the tank. the hose for deterioration, Fuel pump diaphragm could also be suspect

Can the spark jump a 3/8" gap?

 

[Tony331980]

Whoa. Sounds like I got a lot of work to do to get this thing back up and running! I want to learn to work on it myself though so I'm willing to take the time and get my hands dirty. Thanks for the info!! I'm going to get to it this week and I'll let you know if I beat it or it beats me.

 

[racerone]

Did you install a new impeller in the water pump ?

 

[jimmbo]

Whoa. Sounds like I got a lot of work to do to get this thing back up and running! I want to learn to work on it myself though so I'm willing to take the time and get my hands dirty. Thanks for the info!! I'm going to get to it this week and I'll let you know if I beat it or it beats me.

No, just some Basic Troubleshooting