1971 Evinrude 25 HP Lower Unit?

[alderman]

I have searched all the previous post and still have not figured out if I have a Problem.<br />Last year had a problem with what felt like hitting a underwater object when running WOT, adjusted shift linkage and replaced prop. That seemed to cure that problem. Rebuilt carb this year and motor ran 100% better. <br />Last time we had it out it broke two shear pins without hitting anything that I could feel. The motor does not act like it is trying to jump out of gear, but what would cause the shear pins to give up just running down the lake?<br />I don't think it is ideling to fast after the carb rebuilt because it is slower and smoother now then it has ever been. Don't have a Tach to check it with, but it sure sounds better.<br />I am about ready to tear into the lower unit and start looking at clutch dog.<br />Sure hope some one has a better and cheaper idea.<br />Thanks for any help<br />Ray

 

[Goodoleboy]

Re: 1971 Evinrude 25 HP Lower Unit?

Your lower unit has nothing to do with shearing pins.<br /><br />Your prop has to hit something to cause it to shear a pin.<br /><br />Where are you getting your pins from? something dont add up. Either your useing the wrong sised pins or your hitting something.<br /><br />Good luck!

 

[alderman]

Re: 1971 Evinrude 25 HP Lower Unit?

Thanks for the reply< should be the right size pin's manuel calls for 3/16 x 1 1/4 inch. Getting the brass ones from local marine supply. They seem to fit tight on prop. shaft and prop.<br />I thought maybe if it was still trying to jump out of gear that might cause the shear pins to give up. I know I did not hit anything the last time out. Both pins broke after running for awhile and then shutting down to fish, After restarting no drive to prop in foward or reverse. Like they broke when it was put in gear.<br />Ray

 

[R.Johnson]

Re: 1971 Evinrude 25 HP Lower Unit?

Try a steel pin. I shift dog jumping out of engagement can shear that brass pin.

 

[alderman]

Re: 1971 Evinrude 25 HP Lower Unit?

Thanks for the reply, thats my thinking also. Steel ones would need to be stainless, otherwise there would be a rust problem. I haven't found any local marine shops around hear that carry stainless steel only brass. I guess some mild stainless 3/16 rod cut to proper length would work, unless someone knows where to get precut stainless. <br />If that is the problem then I guess a rebuild on the lower unit would be the best, sure would like a cheaper fix. If I go to stainless what are the chances of damage to the lower unit if I do hit something?<br />Ray

 

[Goodoleboy]

Re: 1971 Evinrude 25 HP Lower Unit?

They are just plain mild steel. But black oxided to prevent rust.<br /><br />Useing brass, you just as well stick uh stick in it.<br /><br />I would use a 3/16 roll pin. some people call em split pins. You can getem at auto parts place.<br /><br />Theyer heck of alot tuffer than brass. On a scale of 1 to 10... brass being 1 roll pin will be bout 9.<br /><br />Good luck!