Uncertainty regarding Sierra Gear Case Seal Kit

[STEVEN HOLM]

Working on a real nice 1972 Evinrude Fastwin.  Converting from long shaft to short shaft.  Wanted to do a complete job here, putting new seals in place, prop shaft, drive shaft and shift shaft.  Seems clear, of the two seals, using one in the head assembly on the prop shaft makes sense.  Why? two will not fit.  However, why does Sierra have two in the kit?  They appear to be the same part.  Now, to the drive shaft seal question.  Again, two are included in the kit, both seem to be the same part.  Only one is illustrated to be utilized on the Marinengine.com website.  In this case, room for two in the casting beneath the water pump.  Does anyone have answers to these inconsistencies?  There are situations where newer models have an inner and outer seal, they are mounted one on top of the other, each facing in an opposite direction.  Purpose, keep the water from intruding on one end, gear case grease in place on the other.  In these cases the Marine Engine website illustrates that being the case, depending on year and model. I believe, placing one under the water pump, on the drive shaft is the correct route to take.  However, don’t want to have a failed pressure test and take the gear case apart and have to reseal it again.  Thanks for the help!

[Bob Wight]

Not sure about why the kit includes 2 prop shaft seals if they are in fact the same size but seal kits often include multiple seals that would fit different horsepower size models.   On my 1972 Sportster 25hp, there was in fact 2 original seals used on the driveshaft mounted one over the other, facing in opposite directions as you noted.  Here’s a picture of the 2 original seals I pulled, lower seal on the left upper seal on the right.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[STEVEN HOLM]

Bob, Thanks for the input.  The two will fit under the water pump, makes sense to use them.  I examined all the seals in the kit, with a magnifying glass.  In the rubber, on the prop shaft seal is stamped N182031, also OEM.  Same on both.  Difference though, number 2 stamped on one and a number 3 stamped on the other.  Looking at a second Sierra bag, Seal Kit #18-2884, same exact stampings including a 2 on one seal, 3 stamped on the other.  Drive shaft seals are free of any stamping, in the metal or rubber seal material.  On Marine Engine’s website, the Sierra seal for the drive shaft has a part # 18-2032, a note saying “1 required per assembly”.  Though not shown in the expanded depiction of the gear case (diagram) which includes all the Reference numbers, examining the Gearcase Head Assembly #038757, only $226.43, ouch!   Here it makes a note, to purchase one Sierra part 118-2031 seal.  In addition to all of this, had not noticed something before.  Clicking ones way through, in the Marine Engine website, to the Sierra Seal Kit #18-264, an expanded list of what is included: 1 each of the seals for the drive shaft and the prop shaft with the part numbers 18-2032 and 18-2031, respectively.  The question, why are 2 of each placed in every kit when only one of each is required?  Will leave it there!  Thanks again for your assistance, Steve

[fleetwin]

STEVEN HOLM wrote:

Working on a real nice 1972 Evinrude Fastwin.  Converting from long shaft to short shaft.  Wanted to do a complete job here, putting new seals in place, prop shaft, drive shaft and shift shaft.  Seems clear, of the two seals, using one in the head assembly on the prop shaft makes sense.  Why? two will not fit.  However, why does Sierra have two in the kit?  They appear to be the same part.  Now, to the drive shaft seal question.  Again, two are included in the kit, both seem to be the same part.  Only one is illustrated to be utilized on the Marinengine.com website.  In this case, room for two in the casting beneath the water pump.  Does anyone have answers to these inconsistencies?  There are situations where newer models have an inner and outer seal, they are mounted one on top of the other, each facing in an opposite direction.  Purpose, keep the water from intruding on one end, gear case grease in place on the other.  In these cases the Marine Engine website illustrates that being the case, depending on year and model. I believe, placing one under the water pump, on the drive shaft is the correct route to take.  However, don’t want to have a failed pressure test and take the gear case apart and have to reseal it again.  Thanks for the help!

Yes, Sierra makes some of these seal kits to fit a wider range of engines…  So, there may be extra parts in there you do not need.. Was there any instructions in the new kit?  You must be very careful, sometimes there are slight differences between the two seals, such as different OK, or different ID on the seal lip…  Take your time and compare the seals before assembly…

[STEVEN HOLM]

Fleetwin, thank you for your input here.  There were not any instructions, that is unfortunate.  I have utilized the Sierra carb. kits frequently, they have many, many extra parts included.  You make a great point about the potential for slight differences between items in the bag.  Just ordered the individual OMC labeled parts from MarineEngine.com.  Will compare these to the Sierra counterparts, go from there.  I have several more of these later underwater units to reseal, want to have my ducks in a row moving forward.  The underwater unit on this 1972 Fastwin is the first one I have done.  They are not as easy to work on as the videos on Youtube would have one believe.  For example, those old seals did not just pop out for me.

[crosbyman]

servicing most split case LU is well covered in the johnson bible available for $20 ..just download what is likely the  cheapest  400 pages+ book you can find these days. just print locally double sided and bind.   keep the file on your laptop, pc  friends PC etc…

 

even if it does not cover 1972  a split case is a split case LU  🙂

https://watercraftmanuals.com/outboard/johnson/manuals/johnson-302231.htm

 

Joining AOMCI has priviledges 🙂

[STEVEN HOLM]

Crosbyman, thank you, will download that manual!  Need all the help available, Steve

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crosbyman

[crosbyman]

you will find a lot of similarities with the FD series of older engines.   carbs , magnetos , lu  .

I got mine double  side printed  in 2  books of about  225+ pages  and bound with a large spring binder  with front and back  cover  sheets in  plastic .  Makes for easy flat reading on the bench. 🙂

pressure testing will confirm you did a perfect reseal  job…. some folks don’t bother and just  refill the LU mid-seaon.

https://www.bing.com/videos/riverview/relatedvideo?q=danbar+gear+case+pressure+testing&mid=144AD90360F195315D84144AD90360F195315D84&mcid=79AF59C67C1643CDB536DBB9E05AC0D9&FORM=VIRE

Joining AOMCI has priviledges 🙂

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