Johnson Seahorse Starting Issue

[Bondy123]

Hi, i recently finished doing some work on a '57 johnson 18 hp i bought and it wont start. When i put it in a test bin and put the choke on and pull it it will do one of 3 things. 1: it will do absolutely nothing 2: it will "sneeze" or 3: it sounds like it wants to run for a split second but then dies. I have no idea what to try next. Compression it good, flywheel key is not sheared, points are at 20 thousandths, carb was cleaned. Any help appreciated

 

[gm280]

Have you check to see if fuel is in the carb? Can you mix up a 50:1 fuel ratio in a little bottle and squirt some in the carb and see if it will fire and run for a few seconds? If you can, then the fuel pump or primer bulb is bad. Just remember, don't use starting fluid on any 2-cycle engine. There is ZERO lubricant in starting fluid and it will start up dry. :nono:

 

[Bondy123]

I can shoot some gas in there and see a little later. The motor uses a pressure tank so it doesnt have a primer bulb or a fuel pump.

 

[oldboat1]

24:1 fuel mix. Idle speed air/fuel mix needle 1 turn out from seated, h.s. needle 3/4 out. The primer pump button is on the top of the tank -- should hear fuel going to carb and see the glass bowl on the side of the powerhead fill (Make sure the filter is clear, and the gasket is in place -- thumb nut snug.) Should check spark with an adjustable tester (about 3/8"). If you changed out plug wires, make sure the inner wire is in contact with the spring connector in the boots, and contacts the spike in the coil(s). Coils should be new or newer -- no cracks. Depending on spark, you may need to clean and readjust points. Plugs should be J4s (?) gapped at .030.

Should check compression if you haven't done that already.

great motor!