My 86 40hp Yamaha will run great and smooth at higher RPMs and when you just start it, will run for 10 seconds or so fine then cough and cut out. Will run well and longer as long as the rpms are higher than idle. It will also cough when bringing it back down from higher rpms and die. I cleaned out the carbs twice, checked the bowls after it coughed out and they have fuel so the floats arnt sticking. Would this be a timing issue? Has what looks like strong spark, blueish white. If you continuously hit the choke switch on the ignition it will run at idle so it should be a fuel issue, but I meticulously cleaned out the carbs, flushed all lines with clean fuel, cleaned out the fuel filter, replaced fuel pump. Im getting rather frustrated because usually these engines run forever and have few issues and I keep throwing parts at this one and nothing seems to help. Also, how hard is it to rebuild the lower units on these, or at least replace the clutch dog piece? Reverse seems to be engaging but forward is not fully engaging, adjusted shift rod many times to no avail. Thanks
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