what year merc outboard?

[steelhead49]

I have an older merc outboard serial number 3577398 The cover says Thunderbolt 500.Can any one tell me what year it was made?I also need anew prop any suggestins? Irun this motor on a17 foot express duck boat that fully loaded weighs approx1750lbs.What size and pitch prop should I use?? THANKS!!

 

[JB]

Re: what year merc outboard?

Hi, Steelhead.<br /><br />Welcome to the Board.<br /><br />I'll move this to General Outboard for you.

 

[rickdb1boat]

Re: what year merc outboard?

1973 Model 500(50)<br /><br /> web page <br /><br />As for prop, if it's a lightly loaded, I would go with a 10-1/4 X 13, which is the only one the Michigan prop selector shows. 13" sounds about right for your boat, depending on the total boat weight when loaded. What are you running now? You can always have a prop shop re-pitch it 2" either way, if need be. Are you having problems with it??