I have an older 2.5 hp johnson I bought with my 10' jon boat this winter.  It will start and then die.  It has new gas in it and everything (mixed 50:1) What else could it be?

The first thing I would do is clean the carb.

Second would be to clean an gap the points

Since it does start, it's probably the carb, easy way to check that is to spray a mist of premixed gas into the carb and see if you can keep it running.

Thanks W2S I was wondering about the carb but didn't want to take anything apart until I got a bit of imput.  I was also told about the points from a few people...how do you clean those?

well i got it running with a little bit of playing with the screws on the front for fast speed low speed (rich and lean) got it will idle and everything just it sounds a bit clunky probably just needs a good run (sounds like a lawn mower for the first bit when you start it up in the middle of spring after sitting all winter) I broke the choke thing though that pulls the choke forward and back so have to order another one but other then that it sounds and looks like it may be a good motor.

To set the points, sometimes they have an access port in the flywheel. It will a thin metal cover hold in place by one, sometimes two screws. You use a burnishing tool, which most likely you won't have to clean them. A second option is fine emory cloth. If you can't come up with that, use a match book. Then gap them so a .020" feeler guage slides smoothly through them without moving them but has a slight drag on it.

It's not actually "cleaning" the points. After a while the constant zap of electricity going thru the points creates a high point on one side. This makes the points actually close sooner than they are supposed to which changes when the spark ultimately goes to the plugs. It changes the timing. Get a point file at the parts store. Emory cloth or a matchbook will do but a point file is best. They are only a couple of bucks usually. File that high part off, file any crust off the other side (don't file off too much, just a few scrapes will do) and then clean the shavings from the points with a small cloth dipped in rubbing alcohol. Let it dry for a few minutes as alcohol is flamable, check the gap, reset as needed and you should be good to go.

Come to think of it, points are cheap at the parts store. They probably won't have a listing for those points so remove them, take 'em down to the parts store and have them match them up with new points and reinstall. That's probably your best bet. The points in that engine are probably pretty old and burnt anyway.

After messing with the points, either adjusting the old ones or installing new, always check the timing because the point gap affects the timing as well.

Hope this helps.

           

Thanks....I order both a file and new points to have on hand ill try the file to clean them up altough they don't look too bad at all but they are dirt cheap so wont hurt to have extra just incase.   Thanks for all your input.

Actually, you should never file a set of points, works in an emergency but if you file them, you should replace them as soon as possilble. Most point files are still too course and leaves scrathes in the platnum surface, if they are pitted or have a burr, replace them.

Points will get an oxidized glaze over them when let set for a long time and you can "clean" that off but not with a file.