Re: Mercury500 Thunderbolt 50HP
ScottG76 states:
Have two quick questions. I'm looking at picking up one really cheap ($200) from a long time friend. He left the lower unit off the motor and now there is rust up and down the gear "spine" that connects the motor to the gear case. Can this be cleaned up or does it need to be replaced?
Maybe maybe not. Rust around the place on the driveshaft where the waterpump seals run are the major issue on the older mild steel drive shaft engines.
Are these good motors or should I start looking elsewhere?
They are very good engines fer fresh water, not so hot fer salt water. The mild steel drive shafts rust, (as you know). 
Supposedly it runs and obviously I would turn it over before I purchased, just skeptical because it's old and I don't know how well this motor holds up.
Keyword: supposidly. I would also be "skeptical" of ANY older engine that was taken apart and left to rust by the owner. When I buy one of me old girls I look ta see if they are virgins, (wire nuts on the old silver blocks still in place). If they have been worked on my "SKEPTICIZM" INCREASES EXPONETIALLY. Not so worried by carb R & R et al, but crackin' the crank case gets me attention.
Factory work at Mercury is a known quantity. After factory work is not. The only rebuild I ever did was a 1976 1500 inline6 that had pistons mixed and matched so I had ta buy 6 new ones, OUCH!
Plus it's a 4 stroke and I didn't even know that they made 4 stroke outboards that long ago, lol.
You obviously don't know much about outboards. The Merc 500 was a two stroke. If the feller tryin' ta sell it to ya claims it is a four stroke ya may have much more ta worry about then the lower unit.
BTW: the Homelite Bearcat was a similar vintage four stroke.
This would work out perfectly if I could use it. It would mean that I got a 16 foot runabout restored and sea worthy for around a grand! Thanks for the help guys.
I don't know how much help I have been. Before I buy any old engine I fire it up and watch it run and idle n' shift it, and I also check the cornpression if it is priced as a running engine. $200 is too much ta pay fer any parts engine in rusty pieces, IM not so HO.
Good luck, JR
