not running right

[lil mikey]

hello All,,I have a 1993 evinrude 50 hp,the motor doesnt run past 4200 rpm,it's not pulling like it should. I changed fuel filter,fuel source ( ran boat out of gas can). when I pull the top plug wire off it does still run a lil ruffer, when I pull the other off it kills the motor,I am pulling off one at a time. Does this sound like a plug wire or coil? I did change spark plugs. any help would be great,,,thanks Mike,

 

[Joe Reeves]

Re: not running right

Start your trouble shooting procedure as follows:

Remove the spark plugs.

Check the spark to see if it will jump a 7/16" gap with a strong blue lightning like flame... a real SNAP! Does it?

You can use a medium size philips screwdriver (#2 I believe) inserted into the spark plug boot spring connector, then hold the screwdriver shank approximately 7/16" away from the block to check the spark.

Then with both s/plugs still removed, check the compression. What are the individual psi readings on the cylinders?

 

[lil mikey]

Re: not running right

joe,thanks for the reply. compression is 110 & 105,,,,spark jumps with solid blue arc,,one thing we did find was the nylon roller on the throttle thats works with the timing was only half there,the boat ran great last time out and today it didnt ,,I also ordered a ign coil and wires along with the roller. We are thinking that half the roller was in when the boat ran good and when it didnt the roller ,,cam,,bushing wasnt in place.. Again,,thanks for the help !

 

[Joe Reeves]

Re: not running right

Yep, a broken throttle cam roller will really screw up the works.... good catch.

 

[lil mikey]

Re: not running right

Yep, a broken throttle cam roller will really screw up the works.... good catch.

time will tell,,,thanks again for the response joe

 

[digidog00]

Re: not running right

I am having a similar issue with my Johnson 70. Wont go over 3000 RPM. Cant figure it out. Looking forward to your results