1953 25hp Evinrude Big Twin

[oldboat1]

'53 is different on the face of it (parts diagram). Need input from someone with hands-on experience.

(edit. found a '55 diagram, and it's the "new" style like your '56. '53 must be on the cusp....)

 

[oldboat1]

Do a search here in iBoats. (saw a thread on a '54 electric start, although water pump apparently not referenced in that one).

 

[JoeFromAkron]

Thanks for the info and ideas oldboat! I might make a useful hobby out of these old motors yet...
I've been digging around for a few days. I don't think there are a lot of people with these, or at least those that do have them know what they are doing with them, but I still found lots of good info. Like the whole service manual for the Johnson motors from the boatinfo.com website. I made on big .pdf file (If anyone wants it I can share that) and printed it (I work at a printing shop) so I should be able to figure out whatever I need to. It's pretty detailed. Now if I could find my flywheel puller ..... My 2 year old son thinks dads tools are the best toys and I think he made off with it.

 

[oldboat1]

Nicely done. Would like to follow progress on that one, so hope you continue to do some posting. All good.

 

[HighTrim]

Ok, for testing the coil continuity......

If you put your meter leads between the lead that goes to the points, and the ground lead, that tests your primary winding in the coil. It is a short, fat wire, and almost never fails. Even in the old coils. It should show 0 ohms resistance.

If you put your meter leads between the spark plug boot, and the ground lead on the coil, that tests your secondary winding in the coil. It is a long, thin wire, and on a bad coil is often the issue. You will get between 3000 to 8000 ohms resistance here, depending on the coil manufacturer, if it is good. The trouble with testing this one, is sometimes it is just fractured, and your meter will show continuity. Then, when the coil heats up from running, the fracture will separate from expansion, and the coil will fail. You will get back to the dock, test it, and will seem ok. That is where a tool like a Mercotronic comes in handy for testing, as it puts a load on the coil while under test.

So, if you are trying to simply test the spark plug lead, and try to put a lead on the boot, and one on the coil ground, and am expecting to see 0 ohms resistance, you wont. Doesn't mean your spark plug lead is bad.

For the water line, you are correct, it is not like the newer motors. Different beast.

 

[JoeFromAkron]

Ok, for testing the coil continuity......

If you put your meter leads between the lead that goes to the points, and the ground lead, that tests your primary winding in the coil. It is a short, fat wire, and almost never fails. Even in the old coils. It should show 0 ohms resistance.

If you put your meter leads between the spark plug boot, and the ground lead on the coil, that tests your secondary winding in the coil. It is a long, thin wire, and on a bad coil is often the issue. You will get between 3000 to 8000 ohms resistance here, depending on the coil manufacturer, if it is good. The trouble with testing this one, is sometimes it is just fractured, and your meter will show continuity. Then, when the coil heats up from running, the fracture will separate from expansion, and the coil will fail. You will get back to the dock, test it, and will seem ok. That is where a tool like a Mercotronic comes in handy for testing, as it puts a load on the coil while under test.

So, if you are trying to simply test the spark plug lead, and try to put a lead on the boot, and one on the coil ground, and am expecting to see 0 ohms resistance, you wont. Doesn't mean your spark plug lead is bad.

For the water line, you are correct, it is not like the newer motors. Different beast.

Thanks for the good info. After thinking about it i have decided to just replace everything except the coils. They are replacments and look pretty new. My understanding is that they almost never go bad as long as they are not the original ones? It would be a lazy move to go through the hassle of pulling the fly wheel and not replace $30 in parts. I plan on using this as my main motor so i want to make sure its right.

 

[JoeFromAkron]

Nicely done. Would like to follow progress on that one, so hope you continue to do some posting. All good.

Ill keep posting if i have an audience The thing seems to be pretty good so I figure water pump, points/ect and it will be good to go. I might replace the head gasket just because thats easy and i can decarb it a bit.

 

[racerone]

????---------There is no seperate copper water tube on those motors .----Do not need one either.--------Just like some of the newer 3 cylinder and 2 cylinder motors today, no water tube required !!!!

 

[JoeFromAkron]

Well today i tried to replace the water pump. After I dropped the lower unit and found the shift coupler, Its at an odd angle to try to get at it and it has to be shifted to reverse (I think) to get to it. Much to my dismay the slots in the screws are pretty rounded off. They also seemed to be corroded and stuck. I tried to get the screws loose a couple of times and probbaly rounded them off a bit more. Im going to find a big, wide flat head screwdriver and try again. I have the screws soaking in liquid wrench. Anyone have any ideas? I dont want to completely destroy the screw.

 

[HighTrim]

Hit it with some heat. Then hit it with penetrating oil. Use a large screwdriver, with a square shank. Then you can put a wrench on the shank, and use it to turn it. Makes it much easier. Worst case scenario you just drill it out. But try not to get to that.

 

[JoeFromAkron]

Im going to have to do something. There is not enough there for a screwdriver. I am thinking of trying to turn it out with a punch and hammer?

 

[oldboat1]

this is in the shift coupler (sounds like the l.u. is partially dropped)? If the coupler is the brass style used in later models, could sacrifice and replace it. Dremel tool?

(I use vise grips, similar to what HighTrim describes in run of the mill cases, clamped up close to the screw.)

edit. if brass connector with one side threaded -- and access only to that screw, might grind off the head and pry the coupler apart to remove the shift rod.

 

[JoeFromAkron]

No Title

Heres what im working with. Im following the manual. You have to drop the LU and access the screw from the back. You only have about an inch or so to work with but the coupler is actually higher than the space so you have to angle the screw driver to get to it. I tried to spin it with a punch to no avail. Im thinking of "modifying" a hack saw blade to cut the bolt off on the back of the screw? I am thinking ill grind half the blade off so i can angle it in there. It will take about a week to cut through it but im not getting a dremel in there. Edit: the picture makes it look wierd but I think its brass. I think a newer style one could work if i could get this one off. I'm also thinking i might try and find a long nut driver and see if i can turn the nut on the back

 

[oldboat1]

thanks. looks similar in design to the "modern" ones. If like the newer ones, could swivel the connector to give side access. But the connector is apparently unique to the earlier models, and can see why you would want to preserve it. Maybe it's quite a bit different (assuming it fits up like the newer ones, but maybe not).

With straight on access, though, you could reach it with the dreaded Dremel and a cutting disc or one of the little grinding attachments. It looks in the pic like there is a little bit of a slot left, so might be able to improve it with a hacksaw blade (rather than cutting it off). Then reach it with a regular shaft screw driver. Presumably have to hold it in place with a needle nosed pliers, or similar. Would try to drop the lower unit a tad more, and/or adjust the shift lever a little to move the connector a little. Whatever it takes. Can you manage to get at the top screw (assuming that's what is showing up there -- would be similar to the brass connectors.)

might want to get one of those mini hacksaws if you don't have one. Not sure how much reach you need in there.

edit. assuming that cutting the head of would give you a chance to loosen the connector's grip on the shift rod, but that assumes the connector is made like the newer ones (slotted).

 

[JoeFromAkron]

What is actually showing is the nut on the back of the screw. I never thought of deepening the slot. I might try that. I think my problem is actually at the nut. It's rusted on the back of it. I was trying to heat it up with my heat gun to see if that would loosen it but that didn't work either.

 

[oldboat1]

impression is the screw and nut acts like a double nut (locks up, similar to a lock washer). If you can reach in and turn the nut a little, you will probably break them loose -- assuming it's a nut there, and not a molded part of the connector. (If molded in, would think it's not threaded -- threaded portion would be on the other end so the connector pinches the shift rod when the screw is tightened down, like your 15.) Takes quite a bit of heat, if going that route, and not sure what metals you have there. Care needed. Some overnight soaking.

edit. see in your earlier post you tried unsuccessfully to spin it. Wish I had some hands on experience with that one. Seems strange that it would be engineered for only the single access point.

edit. bladed screwdriver inserted on the flat side of that nut -- couple of taps (but don't bugger it up).

edit. and actually, any "pinching" of the connector (above) is probably incidental to securing the shift rod -- think it's the screw or hex bolt in the rod slot that secures the rod. Maybe in the newer brass connectors, that flexing or pinching has the effect of keeping the retaining screw in place, like that screw and nut assembly might do in yours.

 

[HighTrim]

Sounds like someone has buggered up the threads of the original connector, and have now run a bolt through it with a nut instead.

Personally, if it were me, I would cut the brass coupler then put on a good one when I re install the gearcase, but that is me. That nut and bolt will be trouble every time you try to drop it.

 

[JoeFromAkron]

Im going to work on something to cut it. Its a real pain to get to. Apparently they expected their impellers to last forever in 1953....

 

[racerone]

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 !!!

 

[HighTrim]

Can you post a pic of what is going on? Should not be that hard to get to if everything is as it should. Maybe something is amiss.

But I do believe someone has stripped your threads, hence the nut and bolt. That could be a problem in the small gap.