Water pump parts questions

I recently ordered a replacement water pump and impeller for my Johnny 25hp. The model # is E25RCSA, which according to those in the know this is a 1980 Evinrude. Well, when the new water pump arrived it did not match up to the old one. The impeller housing has the part number 313543. Apparently this is a heavy duty water pump (with a list price of $66.00 for this part alone - ouch!!).

As I work on getting this motor back to mint condition, will I continue to run into this issue of mismatched parts? Or, will the rest of the motor be pretty much standard (not heavy duty). Seams odd that the model number does not indicate heavy duty.

Thanks,
Steve

Steve,
the model number you given is for a Evinrude motor, not a Johnson.
Also, the water pump part number doesn't match up, which is good news.
You can save yourself some dough. Where did you get that part number from?

https://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1980&hp=25&model=E25RCSA&manufacturer=Evinrude&section=Gearcase+-+25

I recently bought this boat and motor off of Craigs List. The motor came with a cowling from a Johnson 25hp Sea Horse. As you pointed out, the model number indicates it is an Evinrude. The part number from the original impeller housing indicates that it is either a heavy duty unit (year unkown) or it is from a 1978 or earlier Johnson.

The motor must be a Frankenstein, cannabalized from a Johnson and an Evinrude. The top half of the motor is green (under the repainted coat of white). The lower half of the motor is blue. Some parts of the top end are blue, and some are green (under the repainted coat of black). It was converted from a pull start to an electric start as well.

If this is true, then I actually do have a JohnnyRude!

BentStick said:

I recently bought this boat and motor off of Craigs List. The motor came with a cowling from a Johnson 25hp Sea Horse. As you pointed out, the model number indicates it is an Evinrude. The part number from the original impeller housing indicates that it is either a heavy duty unit (year unkown) or it is from a 1978 or earlier Johnson.

The motor must be a Frankenstein, cannabalized from a Johnson and an Evinrude. The top half of the motor is green (under the repainted coat of white). The lower half of the motor is blue. Some parts of the top end are blue, and some are green (under the repainted coat of black). It was converted from a pull start to an electric start as well.

If this is true, then I actually do have a JohnnyRude!

Click to expand...

Yea, Frankensteins are not uncommon. My guess you have a 1977 or 1978 LU with a 1980 top. 1977 marked the start of a new generation of 25hp JohnnyRudes. I don't think earlier LUs would bolt-up to a 1980 top, but I could be wrong.
Btw, I have a 1981 Johnson 25hp. It was good little runner, but now I have some problems with it idling. Anyway, enjoy your new motor!

I also had idle problems at first. Cajuncook1 gave me some instructions on adjusting the slow speed idle which resolved the issue. It appeared as though the previous owner seated the ss idle all the way down, probably thinking is was a loose screw or something. After tinkerin' with it a few minutes I got it idling pretty good.

During that process I noticed there was no water coming out of the tell tale so I decided to replace the water pump. When I removed the lower end I found that it had not been installed correctly, the rubber bushing around the water tube was all jacked up, half of it blocking the water flow. Its amazing the motor still works, I assume it had been run like that for several years. That probably also accounted for the frequent fouled plugs. Previous owner told me he was informed by a qualified outboard mechanic that older Johnsons tend to foul plugs often.

Also finding stripped threads here and there.

Guess this is what happens when you buy your first boat.

Good luck with your motor.

A common cause for frequent fouled spark plugs is a bad or missing thermostat.