Now that the firewall is cut for the pushrods and the hole for the fuel line to the carburetor, I went ahead and sealed the wood with thinned 5 min epoxy. Rubbing alcohol works great to thin out some epoxy so it can be brushed on with a throw away flux brush. I found that sometimes a gasoline engine will spray a little fuel out the intake of the carburetor when it is running a little rich and I didn't want my firewall soaking up that fuel during the engine break-in period when I will undoubtedly be starting the engine rich before it has a chance to be leaned out any.

For the final installation of the DA-50 I applied Blue (Medium) Loctite to the bolts to ensure vibration wouldn't loosen the standoffs. I chose to use hardened bolts with a hex head to fasten the motor to the firewall. The allen head bolts were too hard to tighten enough for my liking, plus the hex head bolts have a wider footprint to apply even pressure to the fender washers I put on them. The key, I think, is to apply a generous amount of force but spread it out a little, that way the firewall will be as strong as can be for those Hare-y maneuvers and abuse I'll be sure to put the plane through (intentionally and by accident).

To get these bolts tight I used a rachet, a knuckle, two extensions and a 7/16" socket. The top bolts were tough to get to and required the knuckle. I am confident that the bolts are tight and will hold!