1953 25hp Evinrude Big Twin

[oldboat1]

Maybe a pic from the other side and the rear, if you get around to it.

Might remove the powerhead, and release the upper shift shaft (drop the entire shaft with the gearcase). P.head removal usually isn't that difficult, but would want to be sure a new gasket is in hand or easily available. (I assume there is no release without removing the powerhead, but maybe possible on the '53.)

First though, think I would want to be sure the gearcase can't be dropped even a little more without hanging it by the shift rod. Stack 2 by 4's or similar under the skeg. Think maybe you could turn that whole screw and nut thing out of there if you can rotate it counterclockwise, little by little. A locking needle nose might allow you to grip the nut and break it loose. Or, if you can reach the screw and nut from the back with a socket and extension, seems like that should work. (edit., seems you already thought of that: #58 post).

Somebody got it together somehow (although maybe buggered it up in the process).

edit. BTW, there seems to be some identifying markings on that nut (pic in #58), so might be a factory assembly after all. If that's accurate, not sure whether it's good news or bad -- good news if somebody can identify it.

 

[JoeFromAkron]

Really ?????---I have worked on these motors and there was never a problem changing the impellers.---Do not judge the factory experts because you have a " problem " with your example !!!

I'm not judging. I'm actually really impressed at how well the motors are made. Am I missing something though? I have it shifted into reverse so that the gearcase drops the lowest it can. Is there something else I should do to get to it easier? Also, since you have worked on these do you remember if they usually have the nut in the back like mine does?

 

[racerone]

I have a complete one in the basement.----------Took the lower unit off another one recently and had no problems doing so.--Rest of the motor went for scrap.---And yes these motors were extremely well built !------Very little plastic that will fail like on many newer motors.------Remove what you have and install a brass connecter as mentioned !

 

[Guest]

Saw this post and like what your doing with the 53 Big Twin.

One point to ponder, I think that motor uses a 24:1 gas mixture. Alot has been said about running such motors on the contemporary 50:1 mixture.

I always thought you could do this with all old OMC's, but I have recently learned that only motors with needle type rod and journal bearings can run safely on 50:1.

Motors built prior to 1956 have brass bushings for bearings and required the extra lubricity requiring 24:1.

Thats a quart to 6 gallons (!) of 30 weight oil

I had a an old 63 Johnson 40 back in the mid 70's that called for 24:1, The local Evinrude dealer said at that time i could use 50:1 with no issue and I did. But it was a 1963 model.

I'm not sure what you're using, but if your engine does indeed have the older style brass bearings, you may not want to use a 50:1 mixture.

 

[racerone]

Well those motors used needle bearings on the rods at the big end.---Used needle bearings for the mains too.------If it was ever worked on and had rods replaced it may have needles on the small end of the rods.---They use a lot more fuel than say a newer 25 HP.-----So you would have to calculate the total amount of oil going into the motor over an hour running to decide on an acceptable mixture.-----I always ran mine at 24:1 in the early 1970's------Had to explain many times to folks that the 1949 QD-10 models did indeed have some needle bearings.----Fact is many folks do not know how well built and durable the OMC motors of the 1950's were.----Many of them will outlive the modern junk.

 

[Guest]

I can't argue with you there, Racerone, I doubt very seriously that the modern Yamaha, Suzuki, Honda and sadly Evinrude engines will be still purring along 50 years from now. They rely on too much high-tech electronics and gadgetry to achieve the emissions and fuel consumption.

Meanwhile, the OMC's and even the alot of the old Mercs from the 50's, 60's and 70's are still going strong.
I'm often teased by other boaters who own these modern machines for running my "old technology" 2 strokes ('98 200 OceanPro, '73 Johnson 25 and '93 Evinrude 25). I often dismiss their comments because they are usually new to the sport and only know what the salesman told them. Those fiberglass meatloaf pans they call boats gives them away.

As you well know, you can buy an awful lot of gas and oil for your older engine for the price of one of those new engines, and you never have to sweat about lunching an $1800 ECM on a motor you bought 3 years before.

 

[JoeFromAkron]

I can't argue with you there, Racerone, I doubt very seriously that the modern Yamaha, Suzuki, Honda and sadly Evinrude engines will be still purring along 50 years from now. They rely on too much high-tech electronics and gadgetry to achieve the emissions and fuel consumption.

Meanwhile, the OMC's and even the alot of the old Mercs from the 50's, 60's and 70's are still going strong.
I'm often teased by other boaters who own these modern machines for running my "old technology" 2 strokes ('98 200 OceanPro, '73 Johnson 25 and '93 Evinrude 25). I often dismiss their comments because they are usually new to the sport and only know what the salesman told them. Those fiberglass meatloaf pans they call boats gives them away.

As you well know, you can buy an awful lot of gas and oil for your older engine for the price of one of those new engines, and you never have to sweat about lunching an $1800 ECM on a motor you bought 3 years before.

I honestly considered financing a brand new motor to put on the old boat. I looked up some of the prices of the parts and was amazed. I had some bass boat guy snickering at me yesterday about my 15 hp. All I could think was I literally got it for free, put in $50-$60 worth of parts about 10 hours time over the winter and I can do the same thing you can. Where I am in NE Ohio there is a popular chain of lakes that are no wake almost everywhere. I am amazed at the amount of money someone will spend to go 5 MPH in a bass boat.

 

[JoeFromAkron]

No Title

Got the flywheel off tonight. I had to go buy a new puller cause my son hid my old one.... It was on there pretty good. My kid thought the popping sound was hilarious and I was mildly concerned I broke something. The points are actually greasy so it's no wonder it wouldn't spark.

 

[HighTrim]

Well, ya got good coils though!

 

[JoeFromAkron]

That's the important part I noticed something strange. The bottom 3-4 threads on the flywheel nut were stripped out. Basically missing.The crankshaft is fine. Anyone know the part number or is it nothing particularly special and I can use any nut that fits. I think it is a 7/8 nut? Cant remember.

 

[oldboat1]

uh, oh. another mystery -- designed that way, or messed up by a PO?

That motor is interesting. The cover with two screws behind the flywheel -- Wondering if It's a t.stat, or maybe part of an automatic choke? Looks like there is a link arm -- maybe throttle advance during warm up?

 

[racerone]

?????---Really, no such thing as a thermostat on that motor and no such thing as an automatic choke either !!!!

 

[oldboat1]

and....what is it? under the cover? really.

Is the flywheel nut stripped? Is it a feature????

(edit. "cylinder water passage cover", on the '56 30hp. not sure what the function is. good flushing point, maybe, whatever the purpose.)

 

[JoeFromAkron]

The nut is stripped for sure. It looks like someone unscrewed it crooked or something and took the threads off the nut.

 

[oldboat1]

sounds like a PO's work was pretty uneven, but hopefully limited.

nice to have a hands on parts source at some point -- sounds like Racerone could be helpful if he decides. might PM him so he doesn't toss something you need. (good luck.)

 

[JoeFromAkron]

There is a place called Bridges Boats in my town. I will probbaly see if they have it. They have been in business for decades and have tons of hard to find parts. Plus I've known the owner since before I could talk.

 

[oldboat1]

sounds like a great source -- able and willing, and hopefully reasonable ($$).

edit. used to be an old-time place in southern Michigan (Cold Water, I think). Never visited, but saw some of their advertising -- lots of old iron. Don't recall the name, unfortunately, but unique enough to be recognized if still there. Also recommend a place on the Eastern Shore in Maryland (mail/online ordering for you) -- American Outboards (Cordoba, MD). Huge stock of old motors, parts. Check for website. Ask for Dora.

 

[racerone]

Place near Coldwater would be -----Hildebrands Marine-----Visited many years ago.--Seemed to want 1/2 of new for parts.

 

[oldboat1]

Yup. Thanks. Think that's it. Pics of the inventory looked interesting, anyway -- never got around to checking further.

 

[JoeFromAkron]

No Title

Home alone with the kid again so I can't do much. I was trying to clean up the magneto a bit and noticed the top thread on the crankshaft is "flattened". I'm sure it has something to do with the nut being stripped. Any ideas what I can do? I'm imagining just filing off the top thread so I can get the nut on but that sounds like a terrible idea