Wilsons Sandbox

Greetings, A small leak (weepage, I think the term is) has begun at the adjuster bolt for the doohickey. I see from the parts fiche there's an O-ring on the bolt that seals the bolt against the exterior engine cover. I'm guessing there's no way to replace this O-ring without removing the engine cover; I've had the cover off three times (once for the doohickey repair, once to replace a broken counterbalancer weight, and the last time to replace the original gasket that leaked after the counterbalancer weight repair) and don't want to take it off again, especially since I really glued (gasket adhesive) the gasket and metal mating surfaces together. But, before I fill the cavity the bolt sits in with silicone, I thought I'd ask if anyone has experience with a different fix for this leak. It's my understanding the adjuster bolt has a flange that will prevent it being removed from the engine cover. Also, anyone have a recommendation for a particularly good silicone or other filler for the cavity? I'm resigned to scraping some of the filler out periodically to access the adjuster bolt. Thanks in advance for your replies, Glenn San Jose, CA