rebuild- break-in?

[worley1]

I just had a rebuilt motor put on my boat, 1981 rinker bow rider 15', I had a 1990 Johnson 70 hp power t/t put on it it is a complete rebuild new pistons, cylinders bored 30 over, carbs the whole nine yards my question #1 is what is the proper break-in proceder question #2 the guy that put this motor on said he put a 15" prop on and told me if it was not the right prop he would send me the right one. how do I know if it is the right prop? please help

 

[The Marine Doctor]

Re: rebuild- break-in?

Break in.<br /><br />First tank of fuel mix @ 25:1. NO PULLING<br /><br />No full throttle starts...Midrange and lowspeed only and vary the throttle. Do not sit at any given Rpm for more than 45 seconds.<br /><br />Second tank of fuel mix @ 25:1...vary cruising speeds...May run at Full throttle for spirts of 30-45 seconds.<br /><br />Third tank of fuel mix 50:1...Go have fun.<br /><br />TMD

 

[worley1]

Re: rebuild- break-in?

thanks for your quick response Marine Doctor, do you know anything about prop size?

 

[Ranger Dave]

Re: rebuild- break-in?

I just rebuilt my 4hp. I ran 25:1 for the first tank and vary the speed often. I ran at low, mid and high rpms on that first tank as well.<br /><br />Second tank was 50:1 and drove it at all speeds including WOT.<br /><br />The engine runs like a champ.

 

[Hooty]

Re: rebuild- break-in?

You're gonna have to wait until after the break-in period before you can prop it correctly. Correct proping will require wfo operation, tachometer and speedometer. <br />After the engine is broken in, post back, let us know how it's running and we'll get into proping.<br /><br />g'luck & c/6<br /><br />Hooty

 

[worley1]

Re: rebuild- break-in?

Thanks Hooty I'll break it in then check back with you have a great holliday fishing weekend