This is a 1992 J10ELENA. I totally overhauled it, converting it to a 15hp. It has the 15hp carb and exhaust. Bored to thirty thousands over, new carb, new spark plugs and wire. Engine was broken in according to standard procedures. I now have about 30 hours of run time on it. It starts, idles and runs great, with the exception of it loosing 2 to 300 rpm's at WOT. Explanation: After initial warm-up from a cold start, I throttle up to WOT. The boat quickly gets up to plain and runs at peek RPM for 25 to 30 seconds and then quickly looses 2 to 300 rpm and stays there. If I leave the motor cool down for about 30 minutes or more it runs as I previously describe. Note: The motor is not running hot. It feels like normal temps, oil mix is at 50:1. Things I've tried to do to figure out what the problem is; Tried letting off the throttle then back to WOT, taking the cover off the motor, slightly closing the choke to see if could get a reaction, squeezing the prime bulb, change the fuel pump, rechecked the timing, dismantle and inspect the carb, change spark plugs, checked resistance in the ignition components, even checked the lower unit for binding. All of the things I tried had no effect, the resistance checks were ok.
I?m wondering if I need to increase the main jet a couple sizes to compensate for the thirty thousands increase of the bore?
I?ve simply run out ideas of what to check, unless, I need to get new hamsters to replace the old ones I put back in.
I?m wondering if I need to increase the main jet a couple sizes to compensate for the thirty thousands increase of the bore?
I?ve simply run out ideas of what to check, unless, I need to get new hamsters to replace the old ones I put back in.
