I have a 74 mercury 500 50hp long shaft electric start. SN is 4074870
I have had a few problems with this motor which started out mostly electrical which are now solved. I am sparking on all cylinders correctly and timing is set at max and pickup.
Now the fuel problem I am having is holding the motor back from reaching full RPMs at wide open throttle. I am pretty sure it is getting to much fuel because when i am holding it wide open and pump the bulb it bogs down worse. Also when im holding it wide open and give it a little choke it bogs down worse. So when i pull the fuel tank line from the motor and run it wide open it will bog as usual then i will start running out of fuel and go lean for a few seconds where it shows its true power and rpms, it seems proper until of course it runs out of fuel.
So here is everthing I have done:
rebuilt carbs. twice. soaked 10hrs and sprayed with compressed air.
fuel pump rebuild kit.
new timing belt.
new plugs.
new switch box which solved ignition problems.
tried new gas and different fuel tank: no difference.
i also rebuild the lower unit.
Here are some videos to help see what i see.
running on the river full throttle bog: Outboard motor trouble - YouTube
video of bog in neutral in barrel at home Mercury 500 bog - YouTube
I dialed in new floats on the carbs according to my service manual.
This model carb has no high speed adjustment.
It has ran proper before. And the motor will run all day anything below 70% throttle. idles and accelerates great even under load. idle adjustments are dialed in.
If any pictures, videos, or further explanations would help diagnose this problem let me know. i am now 2 months into this motor and it's not yet 100%
I have had a few problems with this motor which started out mostly electrical which are now solved. I am sparking on all cylinders correctly and timing is set at max and pickup.
Now the fuel problem I am having is holding the motor back from reaching full RPMs at wide open throttle. I am pretty sure it is getting to much fuel because when i am holding it wide open and pump the bulb it bogs down worse. Also when im holding it wide open and give it a little choke it bogs down worse. So when i pull the fuel tank line from the motor and run it wide open it will bog as usual then i will start running out of fuel and go lean for a few seconds where it shows its true power and rpms, it seems proper until of course it runs out of fuel.
So here is everthing I have done:
rebuilt carbs. twice. soaked 10hrs and sprayed with compressed air.
fuel pump rebuild kit.
new timing belt.
new plugs.
new switch box which solved ignition problems.
tried new gas and different fuel tank: no difference.
i also rebuild the lower unit.
Here are some videos to help see what i see.
running on the river full throttle bog: Outboard motor trouble - YouTube
video of bog in neutral in barrel at home Mercury 500 bog - YouTube
I dialed in new floats on the carbs according to my service manual.
This model carb has no high speed adjustment.
It has ran proper before. And the motor will run all day anything below 70% throttle. idles and accelerates great even under load. idle adjustments are dialed in.
If any pictures, videos, or further explanations would help diagnose this problem let me know. i am now 2 months into this motor and it's not yet 100%