1985 Johnson 30 HP - Impeller, Bugs, Need Advice..

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deadspot

Cadet
Joined
Jun 8, 2009
Messages
7
Hi, well, thanks to reading a lot of posts and getting a subscription to an online manual (which I am mixed about) I decided to try to replace my impeller (1985 Johnson 30 HP outboard) after noticing a very weak indicator stream.

I was able to remove the lower unit and remove the pump housing. I found some creatures were making a home and I assume they are the reason for the poor water flow (I still need to inspect other areas). I came away with a couple questions I wanted to seek some feedback on if anyone can help.

First, is there anything in particular that should be used to thoroughly clean out debris in the channels around the impeller? Of course I scraped or brushed out what obvious debris (include my little friends). Should I just do my best to flush out with water? I just wanted to make sure there wasn't something else people use or do.

The online manual mentions this when talking about installing the housing - "Lubricate the inside surface of the water pump with light-weight oil." Is this oil like WD-40? And exactly what part are they referring to ? The inside metal ring within the housing that the impeller turns within?

Also, the drive shaft had a bit of rust along the upper portions (above the area of the water pump housing. Is this an issue? Should I just remove the rust? Just wondering if it indicated a problem. (sorry the picture is a little fuzzy)

I attached a couple pictures - thought this post might help others out.

Thanks!
 

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alangf

Petty Officer 2nd Class
Joined
Apr 12, 2009
Messages
105
Re: 1985 Johnson 30 HP - Impeller, Bugs, Need Advice..

deadspot said:
Hi, well, thanks to reading a lot of posts and getting a subscription to an online manual (which I am mixed about) I decided to try to replace my impeller (1985 Johnson 30 HP outboard) after noticing a very weak indicator stream.

I was able to remove the lower unit and remove the pump housing. I found some creatures were making a home and I assume they are the reason for the poor water flow (I still need to inspect other areas). I came away with a couple questions I wanted to seek some feedback on if anyone can help.

First, is there anything in particular that should be used to thoroughly clean out debris in the channels around the impeller? Of course I scraped or brushed out what obvious debris (include my little friends). Should I just do my best to flush out with water? I just wanted to make sure there wasn't something else people use or do.

The online manual mentions this when talking about installing the housing - "Lubricate the inside surface of the water pump with light-weight oil." Is this oil like WD-40? And exactly what part are they referring to ? The inside metal ring within the housing that the impeller turns within?

Also, the drive shaft had a bit of rust along the upper portions (above the area of the water pump housing. Is this an issue? Should I just remove the rust? Just wondering if it indicated a problem. (sorry the picture is a little fuzzy)

I attached a couple pictures - thought this post might help others out.

Thanks!
Click to expand...
Critters in the check tube can cause a weak stream but the check stream is just that, a check stream. There is a lot more water flowing than just the check stream. Unless the critters were actually inside the pump housing (I'm assuming they are mud daubers or something similar) they should cause no problem and should eventually just wash out. If they were actually inside the pump housing (a condition I have never seen in 55 years of boating) I would clean them out and make sure there is no opening in the system that allowed them to get there. If the system is solid the only way they could get into the pump housing is through the check tube.

The lube goes on the metal surface or on the arms of the impellor. A very light coating is all that is recommended. I would use a light coat of vaseline rather than WD40.
 
A

alangf

Petty Officer 2nd Class
Joined
Apr 12, 2009
Messages
105
Re: 1985 Johnson 30 HP - Impeller, Bugs, Need Advice..

deadspot said:
Hi, well, thanks to reading a lot of posts and getting a subscription to an online manual (which I am mixed about) I decided to try to replace my impeller (1985 Johnson 30 HP outboard) after noticing a very weak indicator stream.

I was able to remove the lower unit and remove the pump housing. I found some creatures were making a home and I assume they are the reason for the poor water flow (I still need to inspect other areas). I came away with a couple questions I wanted to seek some feedback on if anyone can help.

First, is there anything in particular that should be used to thoroughly clean out debris in the channels around the impeller? Of course I scraped or brushed out what obvious debris (include my little friends). Should I just do my best to flush out with water? I just wanted to make sure there wasn't something else people use or do.

The online manual mentions this when talking about installing the housing - "Lubricate the inside surface of the water pump with light-weight oil." Is this oil like WD-40? And exactly what part are they referring to ? The inside metal ring within the housing that the impeller turns within?

Also, the drive shaft had a bit of rust along the upper portions (above the area of the water pump housing. Is this an issue? Should I just remove the rust? Just wondering if it indicated a problem. (sorry the picture is a little fuzzy)

I attached a couple pictures - thought this post might help others out.

Thanks!
Click to expand...

I just looked at the pictures. The critters are mud daubers (or dirt daubers) and are not in a position to do any harm as they are external to the actual cooling system. If they bother you just scrape them out with a screwdriver. A certain amount of driveshaft rust is not unusual especially with salt water use. As long as the splines on the shaft are clean its OK. If the splines were corroded you would have caught hell getting the lower unit to separate. There is a recommended lubricant for the splines but I have always used wheel bearing grease and have never had a problem. Good luck!
 
E

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: 1985 Johnson 30 HP - Impeller, Bugs, Need Advice..

If those are in fact mud daubers, then your water intake screens must be bad. The screens are necessary to keep particles out that can damage the impeller and clog the thermostats, so they should be replaced if broken.

Rust on the drive shaft is sometimes an indication that the anodes are not being maintained.
 
D

deadspot

Cadet
Joined
Jun 8, 2009
Messages
7
Re: 1985 Johnson 30 HP - Impeller, Bugs, Need Advice..

Thank you for the helpful reply - yes, the mud daubers were only in the area below the housing/gaskets and not within the housing around the impeller or anywhere like that. But I still need to get back and inspect other areas. I will also inspect the screens - didn't pay attention when I removed them but there must be a hole that allowed the inspects in. I will report back on the outcome in case it helps others.
 
D

deadspot

Cadet
Joined
Jun 8, 2009
Messages
7
Re: 1985 Johnson 30 HP - Impeller, Bugs, Need Advice..

Question for those that have purchased the Sierra Impeller rebuild kit - Item Number 18-3382. It seems the kit comes with only one impeller plate gasket. But from looking at the parts i removed and the instructions of the manual, there should be a new gasket put under the plate and over the plate. Is this not the case? I checked online at the parts that come with the kit and it seems it is only a single plate gasket. Can someone offer some advice?
 
D

deadspot

Cadet
Joined
Jun 8, 2009
Messages
7
Re: 1985 Johnson 30 HP - Impeller, Bugs, Need Advice..

A bump and a restatement of the question - does the impeller replacement require two gaskets - one under the impeller plate and one over the impeller plate? The rebuild kit I purchased had one plate gasket but the online manual indicates two are needed. Thank you.
 
D

deadspot

Cadet
Joined
Jun 8, 2009
Messages
7
Re: 1985 Johnson 30 HP - Impeller, Bugs, Need Advice..

Well, i am replying back just so the next person has this info. It seems according to the diagram of my engine that two gaskets are needed - one under the impeller plate and one over the impeller plate. However, the rebuilt kit i purchased - 18-3382, Sierra 18-3382 Water Pump Repair Kit w/Housing - has only a single gasket.

The online manual i purchased from Seloc online indicates: "Coat both sides of a NEW second water pump gasket with sealer, and then slide it down the driveshaft and into place on top of the water pump plate" - and I believe I have the correct description for my engine.

So it seems I need a second $1.99 gasket which will cost $8 to ship. Either the manual is wrong or the rebuilt kits are not good kits - either way it's a pain. Anyone have experience with this issue on this particular motor?
 
D

deadspot

Cadet
Joined
Jun 8, 2009
Messages
7
Re: 1985 Johnson 30 HP - Impeller, Bugs, Need Advice..

ok - last update - and again correctly so nobody has to deal with the same problem... turns out the online manual from Seloc was incorrect. The folks at Seloc were very helpful and have corrected the text. Only a single paper gasket is needed and the contents of the rebuild kit was correct.
 
rcmickey

rcmickey

Seaman
Joined
Jun 23, 2008
Messages
66
Re: 1985 Johnson 30 HP - Impeller, Bugs, Need Advice..

Gent's I need your help!!! I have 100HP 1991 4 cylinder Mariner that does not pee. I have pulled out the thermostat and replaced the impeller and still no pee. I even pulled out the pop-it valve and ran it with out it. Still no pee. The motor runs cool on the muffs and idles all day without getting hot, but no pee ever comes out. I did get it to pee out the little hole in the pop-it valve, thermostat cover when they were not in, but the cover was on. So what gives???? :confused:
 
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