Johnson hd 25 water pump?

phatnomad

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Jun 6, 2011
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I recently purchased a johnson hd 25 outboard. The impellar looked good but I replaced it anyway. Where is the tell tale on this motor?
 

1946Zephyr

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Re: Johnson hd 25 water pump?

You should see a couple small holes on the back where the water sprays.
 

phatnomad

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Re: Johnson hd 25 water pump?

Water comes out around a sleeve and also out the exhaust. I just want to be sure it is circulating enough water. I removed a plug at the back of the motor that let me see that the impellar is pumping plenty of water to there, a good amount of water at idle and a full stream that shoots 5 or 6 feet out at higher rpm's, this is where the water enters the motor from the impellar tube, I just ran it 10 or 15 seconds since it wasn't getting water to the engine. Maybe I am being overly cautious. Since the water pump is pumping plenty of water maybe I should just run it.
 

F_R

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Re: Johnson hd 25 water pump?

Run it. The mist/spray you see coming out the exhaust relief is the tell-tale. As long as it is not scalding/steam, it is cooling. Besides, a Johnson HD-25 won't run worth beans if overheated because the fuel boils in the carburetor.
 

1946Zephyr

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Re: Johnson hd 25 water pump?

5 or 6 feet stream out the back?? Holy Moly, you're doing good. I hope mine does that good when I get it running. :D
Never knew one of this recipricators would do that well.
 

phatnomad

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Re: Johnson hd 25 water pump?

So a mist of spray means it is circulating enough water? I just ran it in a barrel for about 15 minutes and it is sparaying a mist out 2 little holes about half way up the lower unit. It sprays more out the exhaust than these holes. The mist was warm but never got hot. I think I will take the boat and motor to the lake this weekend and give it a try. Thanks for the help.
 

phatnomad

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Jun 6, 2011
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Re: Johnson hd 25 water pump?

Yeah it surprised me too. That little impellar didn't look like it would pump much water to me. Now this was out of the plug before the water went through the motor. Do you have an HD 25 as well?
 

1946Zephyr

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Re: Johnson hd 25 water pump?

I have a 1941 HD-20 that I am in the midst of restoring. It's virtually identical to your HD-25, but mine was painted silver, instead of sea mist green. That's really the only difference in the two. My powerhead is all rebuilt now. I had to replace all the innards, but it'll be a nice runner, when I'm done. Sea-Way Marine did really well, supplying me the parts I needed. I ended up buying a new crank, rods, pistons and rings for it, so it'll all be new inside. Right now, I'm in process of stripping down and refurbishing the mid section.
 

phatnomad

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Jun 6, 2011
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Re: Johnson hd 25 water pump?

Mine is missing the gas cap. Where could I find one? or a suitable replacement?
 

1946Zephyr

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Re: Johnson hd 25 water pump?

I would try Sea-Way. Since you own a nice little classic, it probably wouldn't hurt to join the AOMCI. There are bunches of people there who have parts for those or have seen stuff. I recently bought some stuff for mine on Ebay too, just to have spare parts. I bought a powerhead for one like yours, for only like 25 bucks, right after I spent over 300 to rebuild mine. LOL Oh well, mine still has the original block. The same guy also sold me a mag plate assembly in great working order, so now I have spare coils and points. I did manage to find a new pair of condensors at Sea-Way, but they weren't cheap.
 
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