Late 80's Mariner 150hp problems

[jermisch]

I bought this boat last year and it had a blown motor. So I rebuilt it and it ran rough all the time. I only had one day out on the water that it ran really good. Other wise it always had a miss. I could never track it down. I replaced the stator 2 times, the CDI boxes, all 6 coils, wires, plugs and trigger. I took it to the shop in town, they replaced the stator again and nothing has changed. It won't come out of the hole with out coaxing. It has ran 55-58 mph before and now I can't get more than 45 out of it. Nothing I seem to do seems to help. I have had all the carbs off and they are clean. I rebuilt the fuel pump. I have replaced several gas lines including the primer bulb. The shop did a leak down test on the cylinders and said everything looks great. I am sick of this motor. However, I want my boat to run so does anyone want to buy the motor so I can buy a new one...probably not. So, does anyone have any suggestions on what I should try next?

 

[emac]

the stator can be tested with a resistance meter, easy to do before replacing it. What cant be tested is the switchbox, and it sound like you replaced that (the cdi boxes?) . I'm guessing here, but maybe the timing is off. the only other thing I could think of is the vent line on your gas tank might be blocked, but that would more likely cause stalling, not rough idle.

 

[haventaclue]

Did you replace the restrictors ,#35 in the diagram http://www.crowleymarine.com/mercury-outboard/parts/299_120.cfm . And where they are located http://www.themarinedoctor.com/cgi-bin/YaBB.pl?num=1254675223