Removal of Extension Housing on 1982 4HP Longshaft Evinrude

I was given a 1982 Evinrude 4 HP 2 cylinder 2 stroke outboard. I endeavor to keep a positive attitude. I have spent a fair amount of time replacing worn and broken parts. Presently my effort to replace the water pump impeller has me stalled in the water, so to speak.

Two bolts hold the lower gear case to the midsection housing. On the long shaft motors, a five inch tall extension housing fits between the midsection and the gear case. On the longshaft, the two gear case mounting bolts are about 7 inches long and go from the gear case straight through the extension housing into the threaded portion of the midsection housing. The long mounting bolts go through drilled out castings inside the extention housing.

I attempted to removed the mounting bolts but I rounded off one bolt head that I eventually filed and drilled off the head. The other bolt head I snapped off after twisting it a full rotation.

I had been working on the motor upside down holding it by the extention housing plate. Hammering the headless bolts downwards with the intent of separating the midsection from the extension housing was unsuccessful. Heating the inside castings, liberally spraying Liquid Wrench and hammering on the mounting bolts, I saw no movement after several tries. There is no visible separation at the seam between the midsection and extention housing. I don't have drills long enough to drill out the bolts. I am out of ideas. Is this something a outboard motor shop could easily do? Steel bolts in aluminum housing are just the worst!

Thanks in advance for any advice.

Rob Harold

And if anybody can help me post photos to illustrate my issue, that would be great. I have tried several times without success.

Pictures might be too big.

Do you have to save the extension? If not, attack it with a hacksaw about a half inch down from the midsection, sawing through the bolts. Then after the extension is out of the way you can work on getting the remainder of the bolts out of the midsection.

I imagined I could cut the bolts that hold the extension housing to the main housing by careful drilling into the side of the housing with the intent to save the housing. It worked somewhat with one bolt but the second bolt resisted and though the housing was on a homemade jig clamped to a drill press table, the drill bit began drifting sideways in the soft aluminum housing. I finally hacksawed through the housing and bolt removing the extension housing. The bolt stubs come out of the main housing easily with just heat and Liquid Wrench. Fortunately, I found a used extension housing on the bay for an OK price. Thanks for the advice. I am moving forward with the motor!