1963 Johnson 40 HP - IMPELLER

[mict_sg]

Hello All.

Needing some help.

I have a 1963 Johnson "Sea Horse" 40 HP model RDSL-25D.

I rebuilt the carb recently and she runs great.

However, the motor is not spitting the water out that it should. It is more of a trickle.

By the fact that water is moving... I am thinking that all the passages are clear. This leads me to believe that the impeller needs replaced.

I bought a manual but come to find out it?s a parts catalog.

Has anyone replaced the impeller on this outboard? Can someone provide step by step directions?

If not can someone point me to a manual that will show me how to remove the impeller?

I have the exploded diagram of the lower unit, but I hate to tear into it without directions.

Thanks for your time. Thanks in advance for the advice.

Seth

PROUD OWNER OF ALL ORIGINAL 1963 CRESTLINE

 

[R.Johnson]

Re: 1963 Johnson 40 HP - IMPELLER

I would really recommend a service manual. You are going to want it to keep your engine in service regarding other maintainence items'.

 

[F_R]

Re: 1963 Johnson 40 HP - IMPELLER

It is not supposed to spit a lot of water when the thermostat is closed. It will spit more when it is open. But should be some water anytime it is running. The thermostat constantly samples the temperature and opens and closes as needed to maintain the ideal temp.

To replace pump:
Remove the lower rear cover (whole bunch of phillips screws)
Remove the triangular access plate on side of midsection. Remove the second plate behind that one.
Remove the lower screw from the shift rod connector inside
Remove the six smaller and one big bolt holding the gearcase on.
The gearcase will now come down and off and the water pump is looking right at you around the drive shaft

Make sure the o-ring is in place on top of the pump housing when reinstalling. It won't run with the hood on if you leave that out
Make sure the o-ring is in groove at top of drive shaft. Lube splines
Use a flashlight and peer inside to make dang sure the notch is perfectly aligned with the hole in the shift rod connector before installing screw. If the screw drags on the notch it will wipe the threads off the screw every time. Then it will fall out 5 miles from the dock.

 

[HighTrim]

Re: 1963 Johnson 40 HP - IMPELLER

Keep an eye on ebay, the seller SEARAYMAN13 usually has what you need. Other than that, outboardbooks.com has factory re prints.

Getting the lu off though is half the battle, although much easier the first time with the aid of a service manual.




This video may help. Copy and paste without the " "

"http://www.meegsonline.com/tmd/waterpump.wmv"

Sorry FR, was typing at same time

 

[mict_sg]

Re: 1963 Johnson 40 HP - IMPELLER

Hello All.

By the fact that water is moving... I am thinking that all the passages are clear. This leads me to believe that the impeller needs replaced.

Do yall agree with my train of thought?

Could the thermastat be the source of my problems?

I had it wide open and it does not seem to kick out enough water.

The motor does not seem to over heating.

Thanks for the comments.

 

[rodbolt]

Re: 1963 Johnson 40 HP - IMPELLER

ok, back in those years they made the 40 in both electric shift and mechanical. the rear cover must either be removed or notched to provide access to the top aft bolt.
saltwater motors get rather interesting to dissasemble
last I needed one the impeller housing was NLA, that engine uses a pressure control ball and spring assy as well as a thermostatically controled cooling system with a duel water pump.
one tube takes water up the other returns it to the pump, make up water is from the screen in the exhaust snout.
been a long time but in the 80's and 90's we ran 9 of them on 3 dories as you cant kill them in the surf.
if yours is electric shift be very careful with the wires, they break easy and last I looked NLA.

 

[F_R]

Re: 1963 Johnson 40 HP - IMPELLER

RDxx is mechanical shift. I was trying to tell you that the thermostat is constantly opening and closing. It will almost always be closed at idle. Don't be so quick to condemn it. Go ahead and slap a new one in if you want.