There's no reverse intake screen above the anti-cavitation plate on my Johnson

[UpNorthDude]

The model is RDS-23 1961 40 HP Super Sea Horse, Super Quiet labeled

The lower unit is a pale green in color, maybe its from another motor?
I recently purchased this motor from craigslist, Its not broken, but
I am wondering why there is no water intake cover, or hole, above the anti-cavitation plate?

Thanks in Advance

 

[jimmbo]

Re: There's no reverse intake screen above the anti-cavitation plate on my Johnson

I don't ever recall a pale green paint on a johnson, except as primer. About the water intake. Can you post a pic of it?

 

[UpNorthDude]

Re: There's no reverse intake screen above the anti-cavitation plate on my Johnson

Here's a picture, I have since removed the hydrofoil fin, but the motor is at my other home currently so I won't be able to take any new pictures for about 2 weeks.

 

[jimmbo]

Re: There's no reverse intake screen above the anti-cavitation plate on my Johnson

Well I was looking in my old evinrude and johnson brochures, in the 1976 Johnson brochure the pic looks like your unit, while the 76 Evinrude brochure photo shows the inlet. Near the end of the prodution run maybe they decided it wasn't needed and they could save a few dollars. I always figured that second inlet was why OMC made 17 and 22 inch shaft motors instead of 15 and 20. Had to keep that second inlet underwater lest it suck air if the antlivent plate was even with the boat bottom

 

[UpNorthDude]

Re: There's no reverse intake screen above the anti-cavitation plate on my Johnson

Thank you, I was just wondering because I didn't want to order any wrong parts.

 

[UpNorthDude]

Re: There's no reverse intake screen above the anti-cavitation plate on my Johnson

I went to marineengine.com and looked up the 1976 Johnson 40 hp and they had different internals, so maybe mine is still something else.

 

[jimmbo]

Re: There's no reverse intake screen above the anti-cavitation plate on my Johnson

Different internals? compared to what? The 76 40hp model was introduced in 1972, discontinued in 1977

 

[UpNorthDude]

Re: There's no reverse intake screen above the anti-cavitation plate on my Johnson

Compared to my 1961 Johnson 40 hp Super SeaHorse

 

[F_R]

Re: There's no reverse intake screen above the anti-cavitation plate on my Johnson

Fer gosh sakes, the 1971-up gearcases won't even bolt up to a 1961. However, the 40hp gearcase was changed twice about 1967-70. The change redesigned the water intake, eliminating the bypass plate, and strengthening the gearcase which sometimes cracked behind that plate. Both of the 1967-70 gearcases will work on the 1961, if the proper water tubes are used with it.

If BOTH water tubes coming down from above enter the water pump housing, it is 1967 gearcase. If ONE water tube enters the pump housing, and the second one goes down into the gearcase, it is a 1969-70 gearcase. The change was made mid-year 1968, so both types were used that year.

EDIT: Years clarified and corrected.

 

[Chris1956]

Re: There's no reverse intake screen above the anti-cavitation plate on my Johnson

Is the whale-tail covering the inlet?

 

[UpNorthDude]

Re: There's no reverse intake screen above the anti-cavitation plate on my Johnson

No I took off the hydrofoil fins and it wasn't under there. I think that you are correct that it is the 1967/68 Johnson 40 hp lower unit, based on the parts lists from marineengine.com (engines older than 1968, they show you the original parts books specific to your model).
Mine did have the two water tubes enter the water pump.



This gearcase is not one that i picked up, it was the one I removed from the engine, sorry for any earlier confusion.

 

[Chris1956]

Re: There's no reverse intake screen above the anti-cavitation plate on my Johnson

Didn't those early 60's motors have one watertube in front of the other? The rear watertube was the return line, back to the water pump.

 

[F_R]

Re: There's no reverse intake screen above the anti-cavitation plate on my Johnson

Gearcase in picture very definitaly is a 1967 or early 1968. No question about it. I was there when it happened (the design change). Note the short brass tube leading to the pump from the water intake screen. That is why it doesn't have a bypass plate that you are looking for.

Now, about the water tubes, they have always been side by side until the change made in 1968. Then the return (down) line was aft of the Up line, and went down into the gearcase instead of into the water pump cap. However, the V-4 motors had one in front of the other.