I have a 15 HP 2004 Nissan 4 Stroke that will idle pretty well. When I try to rev it while under a load, it chokes out. It will die completely unless I back off the throttle. If I slowly work the rpm up, it will gradually get there, but still is working way too hard to push my 19' boat at 2.5mph. When I first got it, 1 year ago, it was basically new from Cabelas. The prop shaft had been rebuilt when someone backed into a rock. It ran great then...pushed the boat to 6mph no problem at wide open throttle.
I pulled the 2 plugs and replaced them with new. Ran better, but still bogged down under a load. If the motor is not in gear, it will rev up fairly decent...but not if I goose the throttle.
Could I have a gas line issue...or did something vibrate out of wack on the carbs? I believe this is fuel injected...I'll have to look tonight.
Does anyone have any ideas of what to try next?
Thanks for any help.