Engine backfires when blower is off help

[waverunning]

"my engine runs perfect when i

"my engine runs perfect when i turn blower on and as soon as i shut it off it backfires and runs crappy,i turn blower back on and it runs and throttles up fine.any ideas what might cause this."

 

[william_m]

Your engine ground is bad. Tak

Your engine ground is bad. Take a jumper to the (-) side and hook to the block.

 

[waverunning]

"i will try the ground and let

"i will try the ground and let you know,i replaced the hole fuel system ,rebuilt the carb,installed new coil all this year and put new points in,the points closed up and it ran like crap,i readjusted them and it ran good for about an hour,i will check my points and the grounds.my boat is a 89 sun runner with volvo penta 4cyl 230a/sp"