Is there any way to tighten up the contact in the brass gears for the throttle in my tiller handle? The motor is a 56 15hp johnson. The gears tend to just grind when the throttle is opened, unless I use a lot of pressure in my grip, and seems like the problem is becoming terminal now. Is this a common problem with these old motors? Is there any place to get these gears?<br /><br />Thanks for your help