a bang when i start my motor

[Meul]

hello there,<br /><br />when i start my motor when it is cold i hear a bang (sort of explosion sound).<br />after that the motor is starting fine and it runs good without troubles.<br />when the motor is warmed up it just starts without the noise.<br /><br />i just bought the motor, the seller told me it is a johnson 20 pk short but the serial/model(20202R)is from an evinrude from 1972. so i guess somebody changed the cap.<br /><br />can anybody tell me if this is something i have to fix?<br /><br />thanks in advance,<br />Jan

 

[DJ]

Re: a bang when i start my motor

Meul,<br /><br />I believe what you are hearing is a lean "sneeze". The big twin OMC's could be a bit cold blooded.<br /><br />More fuel is the answer. Monitor and use the choke (manually-slightly in and out)during warm up.

 

[Meul]

Re: a bang when i start my motor

Hi djohns19,<br /><br />thanks for your reply.<br /><br />yes it could be a lean sneeze.<br />as told before i just bought this motor and tried to start the motor without using the choke just to try out if the motor really needs the choke.<br />i forgot to tell that sometimes it seems as if the motor is going to take out, a sort of little gap, as if the motor is getting no petrol for a little moment, this also happens when the motor is warmed up.<br />this happens not very often but it feels a little uncomfortable when you are on the middle of a big lake or something <br />i have to get used on this motor a little i think.<br />its all new for me.<br />in the middle of the front of the motor, is a round knob that i can turn from left to right<br />do you know if i can use this to give the motor more petrol, or is this knob used for something else?<br /><br />thanks for the help.<br />Jan

 

[steelespike]

Re: a bang when i start my motor

The knob is probably a low speed adjust.<br /> which you adjust at low speed to the best setting.It should be set so the motor responds smoothly as you speed up.<br /> You may need to go through the fuel system from tank to carb clean and repair as required.

 

[Meul]

Re: a bang when i start my motor

hey steelespike,<br /><br />ok thanks for the info.<br />personaly i am not being able enough to do this myself i am afraid.<br />when i open sometihing with a screw in it and try to put it all back on his place i always have left 3/4 of the parts <br />so i better let a professional fix this for me.<br /><br />again thanks for the help guys,<br />jan

 

[Maximerc]

Re: a bang when i start my motor

I have had a couple of Johnsons that did the same thing and a dirt bike too. never would start with out a huge backfire.