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PostPosted: 13 Nov 2017, 19:57 

Joined: 05 Nov 2017, 13:28
Posts: 28
I have a 1973 25 hp evinrude that I thought I would put a new water pump impeller in. Some things seemed unusual while I was pulling it appart. Is the no seal on top of the pump housing to seal the drive shaft? Also there where no gaskets anywhere is this normal? I’ve been wondering why this thing won’t pump water with the muffs hooked up it appears to drawn water from two locations see photo below. Is the only way to run this motor on land to put it in a bucket? Please help!

PostPosted: 13 Nov 2017, 20:25 

Joined: 10 Oct 2017, 11:19
Posts: 33
Location: South Central PA
Parts diagram shows no gaskets and only an o-ring at the top of the pump housing where the driveshaft protrudes. You can easily check this at Crowley Marine's website and many others . This is a similar set up used on '70 and '73 Johnson 6 HPs that I owned, except those didn't use the o-ring in addition to having no gaskets.

Also the water pickup is very similar. Most (or all) of the water is picked up at the screened opening in your photo. There is another opening in the gearcase that looks like a water pickup, but I can tell you that putting muffs there will not enable the motor to draw in water. You do have to submerge the gear case in a container of water to run the motor (unless there is some attachment for that screened pickup configuration that I don't know about).

Additionally, with the 70 - 73 6HP motors, the water level in the container has to be a few inches higher that the screened pickup opening (I think it was 3"-6"). My guess is the same is true with your 25.

1983 Starcraft SL14
1981 Merc 9.8, <15 hrs
1982 Merc 25
1994 Johnson 20
1993 Evinrude 30 - parting
1982 Merc 18 - Parted
1982 Merc 7.5 - sold
1970 Johnson 6 - sold
1973 Johnson 6 - sold
1971 Sea Nymph 12S - Sold
PostPosted: 13 Nov 2017, 20:26 

Joined: 08 Aug 2017, 22:43
Posts: 1
That is normal. Run it in a bucket.

PostPosted: 14 Nov 2017, 10:48 
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Joined: 15 May 2010, 00:38
Posts: 2609
Location: Central Florida
If you have been trying to run it on muffs then there is a good chance you have damaged the impeller already. Only takes a few seconds to start damage.
If you want to run in a "bucket" make sure the water level is up above the level of the water pump. One of the reasons no gaskets were needed is because the pump was designed to be submerged to prime. Once up on plane your water pick up will force water to the inlet side of the pump.
There should be a seal beneath the lower plate on the water pump. That seal is a driveshaft seal. That the one you are asking about?

PostPosted: 14 Nov 2017, 13:13 
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Joined: 02 Mar 2014, 19:52
Posts: 3193
Location: Central FLORIDA - The Sunshine State -
like Pappy said: with boat level, a trash can works well.
if the bucket is not high enough, support it with blocks.

25 Johnson.JPG

25 - johnson 004.JPG

keep the water hose running so the water pump does not suck in air.


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