Got an issue with my 89 150 GT Jonson ran all day stopped to fish and went to load up and motor just cranked and would not fire! Thought it might be the kill switch Nope! Gas starving Nope! I am at lost. There was a mobile mechanic out there anyone have a clue or a connection to the mechanic guy? Fishman

I think it may be a lack of fuel to the motor!

What year is it?

1st check for spark.
2nd check fuel
If the engine ran fine when you shut it down, Then most likely it is the ignition box. On rare occasions, it could be your ememergency switch. Jiggle and wiggle it, then try starting again. Also, you can pull the bottom 4 spark plugs out and crank the engine over, If it was flooded you will purge the cylinders and the motor will try to fire off the top two. Replace the plugs, fire her up, and run her like you stole it.

very first thing is check right above where the fuel line comes into the cowl. there is a small red fuse holder, it is sometimes hard to find. takes a short 20 amp, check this first thing, blew mine and felt the fool when I found it 4 hrs later and 100.00 worth of phone calls later.

Thanks for the coments I will check this out Fishman

Flux capacitor!

Like Mike said ignition box they are famous for them to go out with warning I bet if you tapped on the box it would start or try to start....OPTI

Ive got the same motor and It done basiclly the same thing and I just new my motor was history and what it was Is that I got water in my tank and it dont run on water lol...drained the tank dried it out and filled with goog gas and found where the water was comming in thru the gas cap and she runs like a top now....
One way to check it is to disconnect the gas line from the motor and push the ball in the end and pump gas into an empty soda bottle by pumping the bulb and let it settle a few min. and you will see if it has water in it!!!

I had the same problem with a 96 Johnson 150hp Oceanrunner and after I pulled the wire off of the back of the kill switch it started right up...had a ground