Ok, I just bought this motor a 92 Johnson 15 horse shortshaft. I knew it had a problem when I bought so no surprises. I'm hoping I can fix it.The guy said it rough idled. Well I've been tinkering with it today and here is what I got. It will start but only with the choke on. It does NOT rough idle. It is very smooth but dies shortly after it fires up. It sounds as if it is running out of gas. If you spray carb cleaner in the carb as it dies it will rev back up. You can keep it running indefinatly like that but as soon as you stop thw motor will die. Then you choke it and it will fire right back up. I took the carb. Apart some but couldn't find any jets. I was figuring this might be the problem. The only thing I see that regulates the fuel is the lean mixture control knob.(Does this motor have fuel jets in the carb?) I took that out cleaned it wih cleaner replaced it and kept cranking it throughout all differwnt adjustments. I get the same results still. I also squezed the bulb as it was running to see if maybe it was a fuel pump problem but that had no effect on it. So I kinda ruled a bad fuel pump out. The motor is a 92 two stroke short shaft. I'm hoping someone can give me some suggestions as to where the problem may lie.