1971 65hp merc

[utfyrfytr]

Went to look at a 1966 Hydro Swift with a 1971 65hp merc engine to possibly purchase. Compression checked out fine 100-105 over all four cylinders. When I checked the gear lube in the lower unit it has water in it and was a chocolate brown color. The unit shifts well and there is no noticeable noise or play in the prop shaft. It has been in the same family since new in 66 and always stored inside with annual maintenance until the last two years that a grandson has owned it. He admits to just running it and has never had a problem with it. I can get the boat which still has the original upholstery in excellent shape, the 65 horse merc and a seldom used 10 yr old Merc 40 4hp trolling motor for under a grand. My thoughts was to drain the lower unit and refill run it for a day and see what the new oil is like. My question is how can I tell without tearing it apart to see if a seal kit is all it may need or does it need a rebuild? What would a rebuild cost and can I do it myself? I have most tools and quite a bit of mechanical experience just not on boats. Sorry for the long post and thanks for your help.

 

[fastjeff]

If you have a Mighty Vac (a hand held vacuum pump) you can pull a vacuum on it and see.

Jeff

 

[utfyrfytr]

Would that tell me if it is simply seals or if a rebuild is required? Where can I get the vacuum pump?