Looking at a 4hp that I believe is a 1990 E4RESR that the guys said ran rough when he put it away a couple years ago. It's cheap enough but when looking for parts availability I see that the power packs seem to be non existent for these and other similar models. I know that it's 24 years old but everything else seems to be available. Is there a replacement or is it an anchor when the power pack goes?