I get questions occasionally regarding sealed vs shielded front bearings for engines. A well designed and machined engine will run quite well with a shielded front bearing. Most modern engines come that way nowdays. Occasionally, you can get an engine that is on the extremes of manufacturing tolerances, or where the crankcase has worn due to eating a lot of dust and dirt. For these engines, the fit of the crankshaft and case just isn't close enough to actually seal the crankcase any more. The result is either a lot of leakage out the front of the engine, or an engine that just can't be shut off by the throttle. The easiest (and cheapest) cure for that is using a sealed front bearing. We will be adding kits with these bearings in them over the next few weeks. Right now, we have a kit for all OS .40 to .55 glow engines. If you need one we don't list, call us and we likely have the bearings in stock already. We can make up a special kit for you.
18th Mar 2018