Yet another outboard fault
Yam 92 60F motor. The twice I have had it out for a long run, 60miles or more, it loses power.
The first time it happened I started wiggling the coil feeds and it went OK, so cleaned them up and it ran for about 5 months faultlessly.
Sunday it did it again, after fiddling around I ran it home with 1200 revs missing and poor pickup.
Been through the fuel system with a fine tooth comb, haven't stripped the carbs as there are good filters in the system and the whole thing was spotless. Plus the No2 plug had obviously not been firing and was wet when I got home. (and taking the air box off and plugging the intake for all the carbs with my palm when running sucks up fuel)
So I am fairly satisfied it is not fuel related.
Checked the compression, Rang out the coils, checked all connections and cleaned everything again, nothing found that I would say was a fault.
Ran the motor and getting good voltage on all cylinders from the CDI and good sparks at the plug ends, colourtune put on shows good combustion in each bore.
Now I am going out tomorrow to try it as I can't do a full load test in the driveway but I suspect it will run fine based on what is happening at home now.
Anybody have any suggestions why this fault only appears after running for several hours. I am going to try and borrow a spare coil to try but other than a slightly dodgy one of these I am reaching the end of the things I can check.