Mercury 150hp BlackMax 2-Stroke 6cyl Outboard - No Start

BJ2964

Recruit
Joined
Aug 20, 2020
Messages
2
Mercury 150hp BlackMax 2-Stroke 6 Cyl won’t start... Help!

Hello everyone, I hope I can get some help with this but my mercury outboard will not start! I have replace just about everything on my engine. The stater, the trigger, all six solenoids, six spark plugs and wires, I changed the two computer boxes on the side along with the solenoid switch. Then my old rusty starter went out so I replace the starter as well.
I attempted to crank the boat after I tried to put in some gas treatment to separate the water from the gas but it still wouldn’t start. So I bought a fuel water separator and added that I also drained the gas tank of all the gas and attempted to now at fresh gas to my tank. Being that it’s a two-stroke I have to add the oil to it as well. I have replaced everything except The gaskets to rebuild the fuel pump. But the fuel pump looks fine as it is but I’m going to replace them also. Can anybody tell me if there’s something I missing because I still can’t get it to crank yet. My last attempt is going to be to perform a link and sink! Help!
 

ThomW

Chief Petty Officer
Joined
Aug 8, 2016
Messages
615
Can you be a little clearer with the issues? You say in one part it won't start, but then at the end you say you can't get it to crank? Is the motor turning over and not starting? Or not turning over at all (cranking)? Was it running at some point and stopped? Has it not ran in years?
Have you done the basic checks on it? Compression test on all 6 cylinders? Checked for good spark on each plug? do you have fuel getting to the carbs?
 

BJ2964

Recruit
Joined
Aug 20, 2020
Messages
2
Hey ThomW, The motor was running and bogged down so I found that the stator was no good after testing the wires with a meter. I checked for spark and had only 2 plugs giving spark so I replaced the trigger, coils, wires and plugs. Then I replaced the computer boxes and rechecked for spark afterward, and was getting good spark after that.
again now I attempted to crank the engine and it will turn over good but not start up. What do you think I could do next?
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
39,238
Sounds like wiring hook ups need to be checked.------Verify wires on the SWITCH boxes ( computers you called them ) are correct.
 

racingdave

Cadet
Joined
Aug 2, 2020
Messages
26
You need.... spark.... fuel.... compression and the correct timing and it will run something is not there so i would take a compression test ......check spark on all six coils with a tester st125 and last i would disconnect the fuel line feeding the carbs and crank it over to see if you are getting fuel if so i would take a sample of the fuel and make sure it is good if all the above is okay possible carb issue but i do not think so, if its like mine you have three carbs on it and i do not think all three would have an issue to the point of a no start. Link and sink just do not jump out of adjustment on its own to create a no start.Obviously if you did not wire the stator trigger or switch boxes right sure could cause multiple issues but i would think you would at least get a backfire out of it.
 
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