hard start. spark plugs? mixture?

[Jefffrey]

I have a 1985 johnson 15 hp. After new plugs are put in it usually starts well. when plugs are used for a while there comes a point where it wont start. im wondering if my mixture of 50 to 1 is to rich and plugs are fowling, on the side of the motor it says 100/1. does the mixture need to be 100/1 instead of 50/1. Any help on this problem would be much appreciated. thanks Jeff

 

[oldboat1]

Your oil mix is correct according to current recommendations (50:1). Your air/fuel mixture might be incorrect -- idle mixture needle on top of the carb. Close it clockwise until gently seated, then open 1 1/2 turns and start. If it starts, adjust clockwise until the engine lean misses or stalls, then open 1/4 turn -- should be correct.

Your carb may need cleaning, particularly the idle passages on top under the domed plug, but before that check spark with an adjustable tester available at auto parts stores -- not the inline tester, rather the open air style. Set it for 3/8 inch (open to correction from other listers), and look for a strong, bright spark. You are testing the magneto strength.

 

[F_R]

Dealers were told to remove those 100/1 decals.

 

[Jefffrey]

Your oil mix is correct according to current recommendations (50:1). Your air/fuel mixture might be incorrect -- idle mixture needle on top of the carb. Close it clockwise until gently seated, then open 1 1/2 turns and start. If it starts, adjust clockwise until the engine lean misses or stalls, then open 1/4 turn -- should be correct.

Your carb may need cleaning, particularly the idle passages on top under the domed plug, but before that check spark with an adjustable tester available at auto parts stores -- not the inline tester, rather the open air style. Set it for 3/8 inch (open to correction from other listers), and look for a strong, bright spark. You are testing the magneto strength.

Thanks for the info. i will give all of this a try.

 

[Jefffrey]

Dealers were told to remove those 100/1 decals.

thanks for the info.

 

[racerone]

Check the thermostat.----Check compression and post the numbers here.