Rebuilding Evinrude 225 lower unit = Binding issue

[cecilfrankum]

Lower unit broke several teeth had to rebuild. I have run into a problem never seen before. I replaced the regular gears with the Sierra heavy duty gear set which include pinion gear to match. I also have the OMC tool for setting tolerance from drive shaft bearing housing assembly to pinion. The new lower drive shaft + new pinion measured .025 without any shims added. Per OEM the spacing should be .02. When I tighten the screws on the upper drive shaft bearing housing the lower unit gears bind. Any one ever run into this problem. I have rebuilt several lower units over the past 40 years and never ran into this.

 

[jonesg]

Re: Rebuilding Evinrude 225 lower unit = Binding issue

Is it supposed to be preloaded?

 

[cecilfrankum]

Re: Rebuilding Evinrude 225 lower unit = Binding issue

It is. I had the tool set per the specifications. I believe I may have found the problem after thinking it through. If you place .002 shims on the upper drive shaft housing and measue from the bottom of the shims to the top of the pinion it is very close to the factory spec of .002. Just was not thinking straight by the time I got to that point. I appreciate your response. If this does not work I will be back later today.
Thanks again.

CF

 

[cecilfrankum]

Re: Rebuilding Evinrude 225 lower unit = Binding issue

Anyone working to rebuild a lower unit for the large gearcase ( "O TYpe - V4 V6 V8 1979 - 2006) used by Evinrude & Johnson beware of parts tolerance from Sierra. I worked ten hours to resolve a binding issue when the upper drive shaft housing was tightened. I bought new lower drive shaft (two part shaft) and all the gears-bearing-shims from Sierra versus the OEM. I also bought the shiming tool recommended in the repair manual to determine .020 clearance for the pinion gear. Without any shims the measurement was .032. Very difficult to substract .032 from .020 (factory repair manual tells you to measure difference in reading using shim tool from .020). After several futile attempts to make other alterations I decided to pull the old thrust washer from the trash to take a look. It was 1/2 the thickness of the new Sierra thrust washer Part # 21645. After using the OEM washer the measurement was .005 requiring 3 .005 shims to bring it to tolerance. Solved that problem. Later after assembly of all parts except the prop bearing housing assembly I ran into another problem with tolerance. Could not bolt the housing into the case due to it being "1/8" inch too long. Had to take all the parts back out and checked measure against old parts. Every part in the lower unit were Sierra aftermarket. Found the "1/8" inch in the gear set. Hope this helps someone save many hours. I have rebuilt and repaired my boats for the past 40 years so i am not a rookie on this process. Beware of tolerance on all Sierra aftermarket parts.

 

[boobie]

Re: Rebuilding Evinrude 225 lower unit = Binding issue

Thanks for the good tips. I usually try to stick to the OEM parts. Never had a prob with them in many years.