1955 Evinrude Big Twin 25hp Restoration

carl2782

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Got her fully torn down today. All surfaces where rollers sat look and feel perfect with the exception of one of the rods, which I've included a picture of. It's not rusty, but I can feel indents there. I'm assuming I need to replace that rod. Any other tips or input on where to go from here?
 

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F_R

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I'm surprised that it looks as good as it does. That rod is toast. And the roller bearings that were in contact with it. How about the crankpin that it came off of? And how about the main bearings?
 

carl2782

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The crankpin looks all good to me. You can see in the first picture that it's slightly dark where one roller was, but I can't feel any indent there. The main bearings are the same, some discoloration but no etching that I can feel. I'll get some more detailed pictures of those today.
 
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carl2782

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Got all the parts and ready to start putting this together tomorrow! There's one thing bugging me though (right now, I'm sure there will be more) - I bought a rod and piston assembly based on the above parts list, but the numbers don't match those on the rods and pistons that came out of the motor. My rods show part #302544 and pistons show #302574. Everything appears to be the same, only difference I can identify visually is that the wrist pin on the rod is a bit different. F_R, any help here?
 

carl2782

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Ah, right. Confused me because the replacement parts I bought do have the part # listed above cast in the same spot.
 

carl2782

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Time for an update! Just about got her all back together. Just need to bolt the crankcase up tomorrow when the new lower bearing comes, didn't realize I needed to change that to fit the improved seal. Carb, lower unit, starter, ignition gear etc are all cleaned up and rebuilt with new parts where needed. Should be easy to bolt her together and start up tomorrow!

Been searching for some info on correct running in procedures but haven't found anything specific to these. Can anyone tell me correct oil ratios, rpms, hours for one of these?
 

F_R

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24:1 fuel mix. Run at part throttle for the first hour, with short bursts of full throttle, returning to part throttle. It is advisable to get it up on plane first, then back off to part throttle, maintaining plane. Avoid continuous full throttle operation for the next few hours. Do all this on a boat, on the lake.

EDIT: Oops, posted wrong fuel mix. It's fixed now.
 

carl2782

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Help needed! Can't get this thing to spark at all. It has all new coils, points, condensers, gapped correctly, new leads, boots, plugs... took it all apart and redid everything, just no spark at all. Flywheel magnet is fine. I can move the flywheel and crankshaft up and down about 1/16". Remembered seeing once that that was a sign of bad bearings which could affect spark, but I just put a new centre main in and the others seemed fine. I'll upload a picture of wiring now in case there's a mistake there I'm not seeing. Help! 20160830_154234.jpg
 

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HighTrim

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Nothing is jumping out as wrong there. Ground wires should be pulled in tighter to coil to prevent the flywheel from tearing through them though.

Almost every time I fix a no spark on someones motor that just did a new ignition it is because the points are dirty/hazed over. Even new points should be dressed and cleaned after install.

Run some fine grit through them, or a points file, etc many times, blow off with compressed air, then clean by dipping paper stock, business card in acetone and running that through. Then blow off again.
 

carl2782

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Thanks for the quick reply Hightrim. I cleaned the new points on install, but didn't dress them. Just took the points out again, dressed them up with some 320 grit, cleaned with Acetone and reassembled... same result. One thing that's bugging me is I'm having a hard time getting the points to line up exactly dead centre. Is that a big deal?
 

BigB9k

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Does this engine have the grounding wires? AKA Stop switch?
Are they connected?
If so disconnect them and try. I've yet to see an original one still working.
 

carl2782

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Morning, it does have the stop switch, but it's only on one cylinder. I've tried disconnecting it at the points, made no difference. Can anyone think of anything it's possible I did wrongly in assembling the timing plate to the motor? It all seems to me to go together only one way. I initially had greased the plate which holds it down, but cleaned that all off to allow it to ground. Any other traps there?
 
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carl2782

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Well, spent another 4-5 hours on this this morning trying to get it to spark... pulled all the points again, polished them up with 1000 grit this time, wiped with acetone, compressed air, put back together, acetone, compressed air again. Nothing.Tested resistance from coil to the end of the plug leads, about 15 ohms from both sides of the coil. Everything I tried testing I got the same results as on my Johnson 6hp which runs, except 50% higher resistance on the leads due to them being longer. I'm using NGK plug boots which are for bikes, snowmobiles, that kind of thing - but also tried the older spring and spike type connection and it didn't make a difference.

Heading away with some friends tomorrow, the trip was my target for having this done. So disappointing not to be able to bring the boat because of this! I would maybe be able to spend a couple more hours in the morning if anyone has any other suggestions at all?
 

tomhath

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Have you watched the resistance to ground change when you open and close the points? The coil only has a couple of ohms, but you should be able to see that when the points are open, and it drops when the points are closed.
 

HighTrim

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There is really not a whole lot that can go wrong here.

How are you testing spark? Are the plugs out to make it easier to pull over for testing? Tester set at 1/4" gap, and grounded well? Tester work on another motor?

If the tester is fine, and you have it set up properly, and still not spark....

1. I know the coils and condensors are new, but did you test them at all? If you don't have access to a tool like a Mercotronic or Stevens tester, at least check the primary and secondarys. See link below.

http://www.pochefamily.org/outboard/Coils.htm

2. The coil heel to air gap, is it too large? The coils laminations should be at the edge of the mounting boss, should have it out as far as you can, where you wont catch your nail when you run it up the flat side of the boss. Too far in, no spark. Too far out, they hit the magnet.

3. good connection under the coil from the spark plug lead? did you thread it into the coil?

4. The point gap is at 020 when the flywheel key is aligned with the rubbing block?
 

carl2782

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There is really not a whole lot that can go wrong here.

How are you testing spark? Are the plugs out to make it easier to pull over for testing? Tester set at 1/4" gap, and grounded well? Tester work on another motor?

If the tester is fine, and you have it set up properly, and still not spark....

1. I know the coils and condensors are new, but did you test them at all? If you don't have access to a tool like a Mercotronic or Stevens tester, at least check the primary and secondarys. See link below.

http://www.pochefamily.org/outboard/Coils.htm

2. The coil heel to air gap, is it too large? The coils laminations should be at the edge of the mounting boss, should have it out as far as you can, where you wont catch your nail when you run it up the flat side of the boss. Too far in, no spark. Too far out, they hit the magnet.

3. good connection under the coil from the spark plug lead? did you thread it into the coil?

4. The point gap is at 020 when the flywheel key is aligned with the rubbing block?


Thanks Chris. Couple of good things there I can use. The tester I am struggling with a bit. It was a cheapie, and when I tried it on my Johnson 6 which runs fine I also couldn't see spark - so since I didn't trust it, I also checked with plugs against the block on the 6. Got spark there, so I tried spraying fuel mixture in the plug hole on the Big Twin. Not even a cough and plugs were wet.

I'll test the coil primaries and secondaries in the morning. I'm pretty sure I was getting 0 ohms (continuity) on both those circuits when I tested today, but I'll pull the coils off and make sure that's right. If it is, dud coils?

Lastly, point 2 is interesting in particular. Didn't realize it needed to be super tight to the magnet so I have been pushing the coil heels back as far as I could. Generally this is less than a 1/16th back from flush though, not even as far back as the end of the small bevel at the top of the boss. Are they that sensitive that this could be the problem?

I'm all good on points 3 and 4 for sure. Thanks for all the help.
 

carl2782

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Have you watched the resistance to ground change when you open and close the points? The coil only has a couple of ohms, but you should be able to see that when the points are open, and it drops when the points are closed.


Could you clarify between where and where I should be testing here?
 

carl2782

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So, tonight's updates - still no spark. Put the tester on the other motor again, turned out to be just a weak spark I guess. Would only jump about a 1/8 gap, so tried that on the Big Twin just in case. No luck with that or with plugs against the block.

Adjusted the coils again to be more flush with the bosses - nothing, and then again to be just over in case the magnets in the flywheel were worn. Coil heels were now rubbing against the flywheel in a couple of spots, still no spark. The coil heels are slightly more worn on the bottom, above where the plug wire connects. I wonder if they were not quite sitting flat. How tight is the tolerance we are talking here (to the flywheel)?

Anyway, have the coils out again on the table. Primary shows continuity, secondary just over 10,000 ohms resistance. One thing that seems maybe unusual is I'm getting infinity resistance across the condensers when I test those. Using 2,000kOhms setting on the multimeter for this. I think it's supposed to start at infinity and go back to 0 as the capacitor charges, correct?
 
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