Engine will not stay running

[jwigg21]

I have a 1975 Johnson 115 outboard. I had the engine running great was starting for with no problem and all. The other week I took it out and got a tree branch stuck in my propeller. I took the tree branch out went out and fished for about an hour, but the engine was off. When I got back to the ramp I noticed that the propeller was bent. I bought a new one took it back out to the lake and ran it for about 30 minutes. Right as I was about to head back in the engine just shut off on me. It would start back up but as soon as I give it a little bit of gas it will shut off or if I leave it running it will shut off in about 2 to 3 minuets. I made sure I had fuel in it, made sure I was getting fuel all the way up to the fuel pump, I changed the spark plugs and it is still doing the same thing. Does anyone know what my problem could be.

 

[gm280]

Re: Engine will not stay running

There are four things to support ignition. Fuel/air, Spark, Compression and least but certainly not least Timing... If any one of those is not present, you will not run. So I suggest you check (not guess) each one and verify you have them as a good place to start. You stated that you thought there was fuel getting to the pump but does it equally get to the carb(s)? If you know for certain you have fuel/air, than check for spark. If you also have spark, then next check compression and the timing. You could have sheared or nearly sheared a keyway in the flywheel that has come separated now and not sparking at the proper time. You did say you hit a tree branch and they could have started the shearing of the keyway. Of course that all could be a mere coincidence and you have ignition pack or packs failing now too. So start with the basics and eliminate each and move on till you locate the true problem... However, never assume anything, verify everything...