I don't want to sound like I know more than I do. I am definitely not and expert. This 70 is the first and only outboard I've ever had to lay healing hands on. I know that your 150 is a different beast, but I would still check out the stator and do some other creative trouble shooting before replacing more parts. If you don't have a service manual, you are definitely going to need one to trouble shoot this yourself. Having a mechanic that understands the inner workings of the powerpack and quirks of your motor and is willing to answer questions would be a great help. Just don't try to "fix" more than one thing at a time and you will eventually find the problem. Get a spark gap tester and check your spark both before and after you have the problem if you can. A manual will tell you how to set your tester and any special considerations for your motor. I assume that you looked over all of your wiring under the cowl and checked for abrasions, corrosion, and cracked insulation. Something else you could check would be the fuel system. Run the motor like you normally would that causes it to die. Immediately go to the primer bulb and check it. Is it partially deflated? Does the bulb pump up like normal or does it take a lot of extra squeezes to bring the pressure back up. You could be fuel starved from a partially clogged fuel line, weak fuel pump, or an air leak. You can test with a portable fuel tank to decide which side of the quick connect fuel connector the problem is on. Another place I was able to get a good bit of help from was a forum called iBoats. I did alot of reading there, but I'm afraid that my problem stumped those folks. Of course it also stumped me and my local Johnson guru as well so I don't count it against them. I was able to find plenty of things to check for ruling out problems. Just remember, you need 3 things to make an engine run: fuel, air, and spark. Now you just have to figure out which you are loosing and why.