1955 evinrude 25hp upper crank case seal

[cbouchard]

I am making progress on this motor.....one step forward hopefully only 1/2 step backwards......over the weekend motor ran great, started easily, carb dialed in, no problems. Took it home and it sat in the garage overnight and in the morning noticed oil coming down out of the cowling.....took a look and the side of the motor was covered in oil/gas mix. Believe that it is the upper crank case seal. I looked on line and cannot find any utube instructions on how to replace it nor can I find the part number of the seal.. Any adice, comments would be appreciated. Cliff

 

[oldboat1]

could be the seal. But check the drain/overflow (?) line that runs vertically on the side of the powerhead.

 

[cbouchard]

The only thing I see that resembles a vertical tube seems to be dry........I looked at my 1960 5.5 evinrude and there is a rubber tube that runs close to the top of the engine down to the bottom...all on the same plain as the crank shaft. I do not see this on the 1955 25 HP. Anyway, if it does have to be replaced is it a difficult job and where can I find the part number. Thanks cliff

 

[oldboat1]

Can't help with the '55, Cliff. Similarities between years and models, though. iBoats starts with '68, but here's one for a 33 hp: http://ww2.iboats.com/Power-Head-Gro...iew_id.1549623 (#12 "oil return", plus connections -- which probably differ). The '55 probably had a copper tube and compression fittings.

 

[cbouchard]

I do see a copper tube and compression fittings......no leaking there. Also, when I look up under the armature plate there is a bunch of oil/grease.....wasn't there before I started to run it. Now just to find the proper seal.

 

[oldboat1]

Try this too, for for various info.: http://www.fiberglassics.com/library/images/a/a7/Evinrudeservice002.pdf

Sounds like it's not the return. It could be just somebody's over greasing under the plate. If seeing fuel mix up there anywhere, though, could be the upper crankshaft seal.

 

[oldboat1]

Oops. That was your initial suspicion (crank seal). Sorry -- don't have a pn on the '55.

 

[F_R]

Do you have a RD-17, RD-17S, RD-17R, or what? Different seals were used that year, according to model number. Also, many powerheads were replaced under warranty that year, which means it may not have the original.

 

[cbouchard]

It is a evinrude 25018

 

[F_R]

Aarrgh. I posted Johnson models. For Evinrude, we need the rest of the serial number. Like 25018-xxxxx

 

[cbouchard]

25018-10002

 

[F_R]

If it still has the original powerhead, seal is 303804, replaced by 0321467 (18-2060 here at iboats).

Hate to say this but you have one of the ones that had a lot of failures. Water got in through the lower seal and destroyed all the bearings. Lower seal is same as upper, if you want to go for it. Good luck.

 

[cbouchard]

If a new seal is put into the bottom does that fix the problem with the water getting into the bearings??or was it a design problem

 

[cbouchard]

Also is there any big trick in replacing the lower seal..is it basically same process as top except off course need to remove the power head..appreciate your advice and ongoing support. Cliff

 

[F_R]

If a new seal is put into the bottom does that fix the problem with the water getting into the bearings??or was it a design problem

It was a design problem. Some genius at the factory figured out they could save a dollar by using a conventional lip-type seal instead of the previous complex carbon seal. Trouble is those 303804 seals were crap and fell apart. Saving that buck cost them a mint. They went back to the carbon seal in mid-year 1956.

Yes, replacing the seal will fix it as good as new.....that is as long as the seal holds up. Replacing it is similar to the upper one. However, if the seal has failed and already done it's dirty work, it is too late.

The seal can be retrofitted with the carbon seal, but crankcase has to be opened up and lower bearing replaced.

 

[F_R]

The 303804 seal was also used on other models and caused the same grief.

 

[cbouchard]

Ok parts on order thanks for your help...cliff

 

[cbouchard]

Your indulgence one more time??do you have the part number for the power head to tower gasket?? 25hp 25018 evinrude. Thanks cliff

 

[cbouchard]

Do you have the part number for the gasket between the power head and tower...thanks again. Cliff

 

[F_R]

303974 replaced by 0304545.