1982 johnson seahorse 4hp waterpump question.

johny 4

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Nov 17, 2014
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Hey im new to this 'forum business' and thought id give it a go as here in NZ finding much info about specific maintainance of my 4hp is really difficult. I was given this engine and have given it a good service (useing info from the very cleaver contributers of this forum).
Its a j4brcnr sn A692011..
So the last mission I have is the water pump/ impeller check, and It didnt start extremly well when i looked and realised one of the two lower unit bolt heads was snaped.. sorted that and found impeller to be in good condition, do I need to use sealant on the housing? What type/brand? Someone said to they used permax or something? Not sure we have that here in New Zealand.. I did scrap some stuff (looked to be old sealant) off the houseing of the impeller where it meets with the plate/metal gasket. It appears the plastic houseing is maybe ever so slighly warped as I could possibly poke a playing card between it and the plate below it (havnt put any sealant on yet , waiting to see what you guys think.. also os there anything else to watch out for when putting lower unit back together.
Thank you very much for ur time in advance..
Guy
 

johny 4

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Nov 17, 2014
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Or maybe a light sand/ file with a stone to flatten and return bottom of houseing to it original completly flat base so I wont need to apply sealant ( or not as much)?
 

Boat Doctor1

Petty Officer 2nd Class
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Sep 29, 2012
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actually -no sealant is needed at all!! dont tighten those upper housing screws too much either as top housing is plastic!! is there any water in lower unit oil?? if so as ur in there now=??--- u can replace the lower water pump seal -thats where the water usually comes from!! also id water?? replace the reat propshaft seal too!! bearing places will have those seals-or marine dealers. Hope u got the broken bolts out?? when used in salt water - usually have to use a torch to heat & remove the bolts or they will break off due to corosion!!
 

johny 4

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Nov 17, 2014
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Thanks for the reply boat doctor, no i didnt see any water in the lower unit so i assume its ok that I dont go crazy replaceing all seals? I think this moter has been well maintained/serviced, as its been looked after by a mechanic...
So my main concern is the gap (maybe only a millimeter) between the plastic water pump housing and the metal plate under it., I will lose presure/vacume if theres a gap right?
 
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johny 4

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Nov 17, 2014
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It will lose pressure/vacume if this isnt resolved right? Surely waterpump houseing needs to be well sealed? Thanks in advance again ur advise is very helpful!
 
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johny 4

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Nov 17, 2014
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Ive taken a photo of the housing, notsure itllbe anyuse, This is the best shot I could take to show the slight gap between plate and housing, the impeller is not in there currently, when its in there It pushes the plate away further, quite alot of force is required to push plate flat to bottom of houseing, otherwise it wont seal, hence why sealant was there previously!? Any advice would be greatly appreciated, im not too keen to buy a new houseing and impeller, I bought sum crc rtv 340 degree celsius silicone sealant, it says I can use it on water pumps.. should I put a 1 or 2 mm bead on both sides of the metal plate/gasket?? Thanks for ur help in advanve again :)
 

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racerone

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Dec 28, 2013
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Post a picture of the bottom of the housing.------Look at the bottom of the housing.----On some pump housings it is they way they are made that shows a gap on the outside edge.
 

johny 4

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Nov 17, 2014
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I sealed the plate to the lower unit matting, then very carefully applyed a very small amount of sealant to the plastic housing, (unfortunately I had to do this twice as after turning the driveshaft clockwise (while looking down at it) i felt more resistance than when i turned it anti-clockwise,strange..., lighbulb went off and i realised that i had installed the impeller the wrong way!!! ( impeller fins pushing insted of dragging if u know what i mean) but yes I understand exactly what u mean 'racerone', there are a couple slight (maybe 1mm) recessed sections when looking at the base of the housing but unfortunatly they are unrelated to my gap, have I done the right thing useing sealer on this? Im abit worried the sealant wont hold or a bit of it might go where it shouldnt! I used the smallest amount possible.. any feedback is super helpful, cheers
 

johny 4

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Nov 17, 2014
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Would really appreciated some assistance on this one.. ive heard 'vic' is the master with these engines. :) .. any input from an expert would be much appreciated .
 

tblshur

Senior Chief Petty Officer
Joined
Aug 24, 2011
Messages
688
johny 4 you sound like a solid thinker so i would say just keep engine temp in mind first few trips out and enjoy your motor:joyous:
 

johny 4

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Nov 17, 2014
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9
Thanks tblshur! I took it out the otherday for its maiden voyage ( under my ownership) and i was stoked as its running really nicely and didnt get very hot at all!
A week prior while servicing the engine I did notice and remove a large plastic obscurity ( maybe a chunk of old sealant) about the size of a drawing pin from the top of waterpump housing (just below rubber grommet that takes copper watertube) guessing this was causeing engine to run abit hot... but it never ran so hot that the flat plate or engine heads paint discolored. Im happy, great wesite! Thanks all for ur help
Now its fishing time! :)
 

raczekp1

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Mar 30, 2010
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1,327
i had some problems to fit gear shaft in hole located in lower unit and fit water pump tube at the same time.
i hope you did it corectly
 
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