I purchased an older 30 inch rear engine snapper mower for my 8 year old grandson to mow their yard. Everything is good except he can't push the blade engage lever forward enough to lock it in because the spring is to stiff, I think. I haven't been able to find an adjustment for the spring tension to make it easier for him to engage the blade. Could anyone give me any advice how to relieve some of the pressure on the spring? Thank you.