Are 1971 Mercury 500 50 hp thunderbolts maintainable?

[Frank Thomas]

Hi. Just joined and first post and just bought my first boat last week. Having fun learning about it.

The boat came with the above motor. I am curious about general opinion of this motor and availability of parts. The prop shaft is sloppy. A mechanic looked at it briefly and found it had 2 or 3 shims in it.

I have taken the boat out three times. It's an electric start and has started great every time and ran smoothly. On one run it was me and a friend and we are both big guys. On a 14' Sea Sprite we started out strong but the motor lost some power shortly into the run. I dropped him off and went out by myself and it ran consistently keeping the boat going 20-25 knots or mph at full throttle. Don't recall the units of the speedo. It seems the boat should go faster?

Finally when I got back to the dock after about 15 minutes I had trouble keeping the idle up and it would stall easily. It restarted ok but had to give it throttle to keep it running.

So any comments are welcome. I am going to look for a mechanic to look at it. Thanks!

 

[Frank Thomas]

I should have added that it is a 4 cylinder 2 cycle.

 

[Scott Danforth]

welcome aboard

everything is maintainable. parts are still available.

however the first thing one should do with any new to you boat motor is replace the raw water pump impeller (or the whole pump kit). your describing either fuel issues or an overheat issue. (motor loosing power)

 

[Frank Thomas]

Thank you Scott!