First off, Glad to be here. I am a Newbie to these forums, but not a newbie to forums in general.
Here goes: purchased this motor (model: j25rwlcos) a week ago from a guy I met at the local lake. Motor was all he said it would be. The motor had been sitting for a few months, but when I went to buy the motor, the guy started it right up for me. It took about 5 pulls then it started. Took the motor home and mounted it on my boat, attached my lines and if fired right up everytime I tried it. Reved it up a little and that seemed fine as well. Changed and gapped the plugs (0.30), drained gas tank and bought new gas and mixed at 50:1. Took the boat out to the lake and the motor started up fine. Gave it a little throttle and that was fine. Gave it a little more throttle and it started to bog down. When it bogs if I back up off the throttle it idles fine again. Tried throttle again and it will start to jurking and will cut off if I leave the throttle accelerated. Always starts right back up.
After playing with the throttle by feeding it slowly after time, the motor started to run fine. Fished a little then started the motor back up. Started and idled fine. Let it run a while easily feeding the throttle and after maybe 20 minutes or so I could get some speed out of it. Never went full throttle though.
Came home and found this site and started reading through the old threads. Got some ideas from various posts, maybe not pertaining to my particular motor but made sense. Replaced a couple of hoses. One from the Carb that runs around the motor to the Fuel Pump and one that ran from the primer to the bottom front of the carb. Started the motor and still the same thing. Played with the fuel air mixture. Eventually the motor got right, but it was with the fuel air mixture at it's original location. 1/4 turn out! ( yes I know, I will get to that part) bare with me please. Purchase a Carb rebuild kit. Took the carb to the local boat repair shop and they put the carb in some expensive machine they had back there. The tech told me that te carb looked pretty clean for starter, but he cleaned it anyway. I explained my problem to him and he told me that it's sound too lean especially with the current fuel/air mixture setting. He told me to start with 1 1/2 turns out. Thats where I started once I re-installed the carb and all of it's attachments. Motor still stalled when given gas. I played with the fuel/air mixture while the motor was running for about 30mins. Then the motor finally started to allow me to give throttle. The motor ran just fine after that. I could turn it off and crank it back up and it still ran properly. Took it out to the lake today and it started right up. Gave it some throttle and the same problem occured. Played with it for a while by steadily giving more throttle. Fianally it would take the gas. Took the boat out , fished a little bit and started it back up to go to another location. Same problem again. Help me im stuck!
Note: I am no boat motor mechanic by no means, but im pretty good with small engines. I know how they work and what keeps them going. I haven't bothered the ignition, timing, points etc. at all though. It seems to fire good to me and compression is good so I didnt fool with it.
Thanks in advance. I will answer anything that I may have left out. Oh, pumping the gas tank ball when trying to accelerate doesn't change anything. Im guessing this rules out a bad fuel pump. Also the fuel filter never stays full of gas nor even half full.