4 horse Johnny cooling issues?

[bitterboater]

I recently got a '71 4 horse Johnson from my wife's grandma. It was stored in her basement for the last 15yrs.

When I tank tested it last weekend, it doesn't seem to produce much water through the 8 holes in the shaft.

It does not have the standard telltale hole near the top at the motor housing.

It runs smooth, and quiet, and it does not seem to have any other issues.

I have not inspected the impeller just yet.

 

[jonesg]

Re: 4 horse Johnny cooling issues?

Change the impellor every 3 yrs anyway.
Its only $12 or so, not a hard fix at all.

A cheap digital infra -red thermometer is handy for checking temps.

 

[Rick.]

Re: 4 horse Johnny cooling issues?

Those holes on the back are your indication it is pumping or not. You won't see a stream ever. Just a steady spit/mist. What a nice gift you got there. You must do the impeller, leg oil, clean and adjust points and give it a carb kit and some new plugs. I would also check the coils and if cracked replace them as well. Give it some grease where ever you feel inclined. Should last you a very long time. Best of luck. Rick.

 

[mikesea]

Re: 4 horse Johnny cooling issues?

I also strongly suggest a new impeller before leaving port.It will breakdown,leave you stranded and possibly allow small pieces of the dried out impeller to travel thru the engine.Nice gift,enjoy

 

[Chinewalker]

Re: 4 horse Johnny cooling issues?

Also - those motors do NOT fully cool the cylinder head or the exhaust cover. The head only gets a little cooling water at the edges and the exhaust cover has no circulation through it at all, so it'll get quite hot. Water circulates through the cylinder block, though, and you should be able to touch the top the block without burning yourself...

 

[bitterboater]

Re: 4 horse Johnny cooling issues?

I just got done pulling the lower unit.

The impeller looks brand new (I'm gonna replace it anyway), the O-ring at the top of the shaft needs to be replaced (broken).

What I saw before I pulled it apart (after tank testing) was a fairly steady mist out of the holes on the shaft.

Otherwise, the plugs looks clean. While testing, the motor got hot, though the top of the motor was not all that hot to the touch.


Thank you all for your responses.

 

[Rick.]

Re: 4 horse Johnny cooling issues?

I just got done pulling the lower unit.

The impeller looks brand new (I'm gonna replace it anyway), the O-ring at the top of the shaft needs to be replaced (broken).

What I saw before I pulled it apart (after tank testing) was a fairly steady mist out of the holes on the shaft.

Otherwise, the plugs looks clean. While testing, the motor got hot, though the top of the motor was not all that hot to the touch.


Thank you all for your responses.

Change the impeller. Based on what you say here I think your cooling just fine. Rick.