Engine motor drags down when blads are on

[johndeerman]

I have a 2082 cab cadet with 20hp twin kohler with 60 in deck . I replaced the front oil seal on shaft an now when you turn the blades on it drags the motor down , but you turn blades off an mower runs fine . what could it be ?

 

[johndeerman]

I found the problem , it was a bad coil . it was just firing on one cylinder . changed coil an it runs an mows just fine .