Please Help Identify My Impeller!?!?!

[stemper57301]

Hello Everyone,
I have kind of a problem I'm hoping someone can help with. I have a johnson 40 hp outboard, but I am unsure of the year it was rebuilt and they removed all identifying tags. A local guy told me it was either a 67-69, but all parts match to the diagram of a 1970-1973. My problem is that i want to change the impeller and have no clue which one i need. I have ordered 2 different ones and neither were right both 18-3006 and 18-3083. 18-3006 is VERY close but the center bushing is too small. I took a caliper and measured the old impellers center bushing diameter and it is .688, 18-3006 is .632 so it is very close. I have spent a lot of time looking through old OMC books and sierra manuals and cant find one with that sized center bushing. If anyone has any clue please help i want to get boating!

 

[SigSaurP229]

Re: Please Help Identify My Impeller!?!?!

Pics of the motor and controls would help, as they will have a different set of controls. 67-69 should be Electric shift 70-72 would be hydro electric and 73 would be manual shift. check the transom tag.

 

[tx1961whaler]

Re: Please Help Identify My Impeller!?!?!

Wrong motor. The 40 hp was offered with a manual every year. It had a Selectric model (the RK/ES series) 1962 through 1970. The 40 never had a hydro-electric or hydro-mechanical gearcase.
Does the water pump have 1 or 2 water tubes?

 

[stemper57301]

Re: Please Help Identify My Impeller!?!?!

The pump has 1 tube coming from it. Any help will be great, as i dont even truely know the year! There are no numbers anywhere other than outdated OMC/Johnson part numbers on things like the head and carb. I will post pics in a bit, it's snowing here right now and I'm trying to get my driveway cleaned up. I appreciate your help guys!

 

[F_R]

Re: Please Help Identify My Impeller!?!?!

Ok, let's narrow this down.

Those two impellers you mentioned should fit any 40 hp built from 1960 through 1973.

Did you have to remove a rear cover (whole bunch of screws) from the midsection in order to remove the lower unit?

No? Then how did you disconnect the shift rod, through an oval access plate, or below the carburetor?

Does your motor have thru-the-propeller exhaust? Two carburetors??

 

[stemper57301]

Re: Please Help Identify My Impeller!?!?!

F_R, no i didnt remove a rear cover. I loosened the shift likage behind the oval access plate, dropped 6 screws out and pulled the lower unit free. I dont think the exhaust comes out of the prop but it only has 1 carb.

 

[stemper57301]

Re: Please Help Identify My Impeller!?!?!

P.S.- The drive shaft is still in the motor it didn't some off with the LU, not sure if it should have or not? Alos what pics would be useful to help identify the motor i can post them.

 

[dew2]

Re: Please Help Identify My Impeller!?!?!

Have you ever tried looking at the welch plug on top the engine with the model stamped on it?

 

[stemper57301]

Re: Please Help Identify My Impeller!?!?!

There is no number on the welch plug apprently it was rebuilt or something and I have no numbers to go from at all

 

[clanton]

Re: Please Help Identify My Impeller!?!?!

I would measure the shaft size, call some of the parts houses, tell them what you have. I just looked at 2 later model waterpump kits, the installation instruction ref 2 difference size impellers, both smaller then what you have. Post the shaft size. I doing a very big house cleaning, may be of some help.

 

[SigSaurP229]

Re: Please Help Identify My Impeller!?!?!

Wrong motor. The 40 hp was offered with a manual every year. It had a Selectric model (the RK/ES series) 1962 through 1970. The 40 never had a hydro-electric or hydro-mechanical gearcase.
Does the water pump have 1 or 2 water tubes?

Based off of the assumption that it is a 1967-1969 then it very well could be a selectric A pic of the motor and a gear case could really help

 

[tx1961whaler]

Re: Please Help Identify My Impeller!?!?!

P.S.- The drive shaft is still in the motor it didn't some off with the LU, not sure if it should have or not? Alos what pics would be useful to help identify the motor i can post them.

The drive shaft should have come out with the lower end. It will be pretty difficult to assemble otherwise.
Show some pictures of the whole motor with the cover on, then both sides of the powerhead so we can see what accessories on on it. A picture of the water pump housing would be good to see.

 

[dew2]

Re: Please Help Identify My Impeller!?!?!

Think he may have buggered up the impeller housing.leaving the impeller pin in and dropping without the driveshaft?? Never get it together without the driveshaft off.Well not with the impeller installed corectly anyway

 

[stemper57301]

Re: Please Help Identify My Impeller!?!?!

Ok here are some pics of the powerhead, LU, and a few others. I'm not sure why the driveshaft didnt pull out, it feels pretty damn solid in there. The housing has 3 screws that go into the lower unit and the driveshaft slides through the center hole, it all pulled out pretty easily, didn't have to pull too hard or anything. the impeller and housing all slid downward off the shaft. Not sure if I messed anything up but it seemed the flow of things without pulling hard or anything.

 

[stemper57301]

Re: Please Help Identify My Impeller!?!?!

More pics

 

[F_R]

Re: Please Help Identify My Impeller!?!?!

Your motor is 1974 thru 1976. Impeller is part number 386165. You have to get it from an Evinrude dealer, Sierra does not make it, and iboats doesn't sell it, that I know of.

That drive shaft should have pulled out easy. It is stuck (rusted) in the crankshaft, and may never come out. Eventually, it may rust so badly that it won't drive any more. Hopefully you can put it back together the way it came apart. You may have to file a small notch in the pump housing to allow the pin to slide through.

 

[1946Zephyr]

Re: Please Help Identify My Impeller!?!?!

P.S.- The drive shaft is still in the motor it didn't some off with the LU, not sure if it should have or not? Alos what pics would be useful to help identify the motor i can post them.

The driveshaft is still in the powerhead? Yikes. You should do what you can to remove it. Spray some PB Blaster up inside there and wiggled it around till it's free. Apparently, the o-ring isn't present either. You'll want to make sure you get a new o-ring on top of the drive shaft, or you'll end up with this issue again.

 

[F_R]

Re: Please Help Identify My Impeller!?!?!

I think you will find that it has the o-ring in an internal groove in the crankshaft, not an external groove in the drive shaft as in years past. Yep, a big "improvement". Yeah, right. Too bad they messed up a good thing.

It was probably left out by the last guy that worked on it, or knocked out, or rusted out. Anyway, it is inaccessable without pulling the powerhead.

EDIT: You will also find that the carbon seal has been eliminated from the bottom end of the crankshaft, and replaced by regular lip seals. Another "improvement". Just like the last time they tried that, back in 1955. Some of those didn't last one year. So sad, newly hired engineers refuse to study the history.

 

[stemper57301]

Re: Please Help Identify My Impeller!?!?!

Wow awesome guys thank you so much. I ordered the part earlier today. Here is my question I want to get that driveshaft out if possible so just a couple of questions. Should I have it in Nuetral,forward, or reverse? also how stuck can it be, I have already sprayed half a can of PB on it and it doesnt budge. Thanks again guys!

 

[tx1961whaler]

Re: Please Help Identify My Impeller!?!?!

It can be VERY stuck. I have resorted to turning the motor upside down and soaking it for days, the using a car jack and vise grips to pop it out.