1963 Evinrude 40 hp lacking power

Eoughphily

Seaman
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Dec 29, 2014
Messages
63
I recently purchased a 1963 Evinrude 40 HP lark V selectric shift. I am able to start it no problem, it idles OK, could use a little tune up, probably a carb adjustment or cleaning. Shifting works, has an even 80 psi using the pull start, haven't checked that yet using the starter. I pulled the fly wheel and examined the coils, no cracks. Cleaned the points, wasn't too concerned with gap as it starts easy. Anyways, undergo, it really seems to be lacking power, especially at WOT. Here is a link to a video I took on the lake today at full power. It has about as much power as my 1956 evinrude 15 hp.

https://m.youtube.com/watch?v=YklOaGeca_4&feature=youtube_gdata_player

Any advice would be appreciated , thanks.
 

Bosunsmate

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Apr 7, 2012
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Cadet, your video is set to private, i cant see it
Have you done a drop test on each cylinder?
 

Eoughphily

Seaman
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Dec 29, 2014
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Oops, sorry Captain. I have fixed the link, thank you. As for the drop down test, I do not have that tool in my inventory yet. Just a basic compression tester from harbor freight.
 

Bosunsmate

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Cool its working.
As for the drop test all you need is your hand and some pliers with insulated handle, just pull off one sparkplug wire and check that the motor drops by some rpm.
Then put back the spark plug wire and do that to the other spark plug. Was the rpm drop down the same or was one less than the other or did one not change things at all. That way you can check whether a cylinder isnt working properly or whether the problem s common to both cylinders.

By the way your fuel tank, the big red plastic one looks bowed in. Is that due to a dent or is it under a vacuum? If its under a vacuum your tank vent might be blocked and that will make the motor starve for fuel.

Nice calm water you have their cadet, its winter gales here in New Zealand
 

F_R

Supreme Mariner
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Messages
28,195
It's running on one cylinder. Do the cylinder drop test to tell which one, then fix the other one. You don't even need the insulated pliers, just pull the plug wire while it is not running, and ground it. Start the motor and see how it runs. Then do the same with the other one. Chances are it won't make any difference with one grounded, but won't run at all with the other one grounded. That's the good one. Grounding the plug wire is not so stressful on the ignition system as just pulling the wire..
 

Eoughphily

Seaman
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Dec 29, 2014
Messages
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Bosunsmate, the fuel tank is new. It does that during storage over night with the tank vent closed. I make sure to open the vent before starting the motor.

Out of all the reading I've done on this forum the drop test is a new one for me. I thought you were talking about the test similar to a compression test but checks to see how well it holds the pressure. I will certainly give that a try, possibly tomorrow. I am? suspicious of one of the coils. Its not cracked, but I can tell its older then the new looking coil, and it has the cloth insulated old school wires.

Thank you for the great advise both of you. I have a question on the drop test. What's the best way to ground the spark plug wire?
 

Bosunsmate

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I think you are referring to a leak down test there, that is quite a level up, never done one myself as ive only got a compression tester. I think they are done more on four strokes as they show whether exhaust valves arent seating etc. Not a problem on a two stroke as theres no exhaust valves.

As for the grounding, yes thats good advice, just clean up/sandpaper back to metal a bolt on the head and slip it on to that
 

Eoughphily

Seaman
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Dec 29, 2014
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Doh!! Well, I don't have a barrel big enough to run my motor in while mounted to the boat I have to do all my tests at the lake. So, going off the thought its probably running on one cylinder, I decided to replace the old coil and wires since I already had them. When I pulled the flywheel off the key was sheared. I was intact yesterday when I examined it before taking it out. Most likely the vibrations from running on one cylinder broke it. Will be picking up a new key Tuesday when the shops are open. Then I can update you on how it runs
 

Bosunsmate

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You have to torque those flywheel nuts down accurately. Too loose they break the flywheel key, too tight you damage the crankshaft and itl go off balance.
Did you use a torque wrench, if so what torque value did you use?
Unusual for it to break loose from one cylinder running
 

Eoughphily

Seaman
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Dec 29, 2014
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Previously when I removed the flywheel I noticed the key was a little torn up from the previous owner. Anyways, got a new key today. Replaced coils, spark plug wires, checked and cleaned the points. Checked and cleaned the spark plugs, one was fouled from not firing as it was clean before I took it out. Now it runs nice and smooth. Unfortunately, its not enough power for my boat. I have a 1973 Rivera 17' fiberglass boat that's been gutted, weighs about 1200 lbs. I've never been on a boat before until 3 months ago when I bought this one. Nor did I know anything about motors or outboards till I started tearing into these old vintage ones figuring out how they work and bringing them back to life (new hobby). So now I'm in the market for a bigger motor. I'm debating between a 1962 evinrude 75 HP or a 1969 evinrude 115 HP, $150 each. Which would you recommend?
 

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