Have a 1974 850 Merc outboard I salvaged off an old bass boat, put it on my new G3, The first three times I had it out ran great, easy 35 mph trimmed down, could have got more. The 4th time I had it out I was on my way back to the ramp running about 20 when it just quit, it started right back up but I couldnt give it more that just off idle throttle or it would die. Got it home checked EVERYTHING. could find nothing wrong, The carbs had already been rebuilt this last [2013] winter and the fuel pump as well. All fuel lines and primer bulb are new. i found an updated fuel pump kit, put it in and a new primer bulb, took it to the lake and ran it hard for 20 minutes, ran perfect. went out the following weekend, made one trip across the lake and it started the same thing, couldnt get past part throttle, I had my wife with me and I had her steer while I squeazed the primer bulb it seemed to gain RPM and the I finally got it to take off. Went to the ramp for a break, and after that had a hard time getting it started, then same thing. On the way in I started messing with the choke, its electric so its all or none but I got it to come up in RPM, but then it lost power again. Before this weekend I installed a low pressure electric fuel pump and re-did the tank pickup. Got to the lake, started kind of hard but then ran fine across the lake. Then when I restarted it to move same thing had to keep choking it to get the RPM up, but once it ran it ran good, but when you throttle back and then try to pick it back up again it bogs down like its running out of fuel. The primer bulb always sounds like its got air in it, and the fuel out of the carb drains has air bubbles in it when you crank it over. BUT, I have no fuel leaks even with the electric pump running or squeazing the primer bulb I have tried 3 primer bulbs with the same result, Its a fuel supply issue, I can choke it and eventualy get it to run. Runs fine in the garage, but not on the water. It ran good enough Sat. to get me a speed warning [28 in a 20] but its still not right. All the timing has been checked, and it ran fine the first 3 times out and then quit. Starts right up at the house but seems to start hard at the ramp. Any advice? I am a mechanic, been doing it for 40 years in one form or another and I have 2 cycle experience.
