1967 big twin evinrude wont crank

crandleman1

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My buddy next door has a 1967 big twin 40 hp outboard. When he bought the boat the guy said it ran its just old. He was able to get it to turn over but never fired up. He said he had sprayed carb cleaner in what he thought was the front of the carb or the air intake where the choke is. He said that is when he noticed it not turning over anymore. On my motorcycle and four wheeler i Have to drain the carbs everytime i let it sit for a long time. I have basic knowledge of my bike but minimal to nothing about boat motors. I checked his battery and it seems to have juice and when he turns the key the motor knocks one time and tries to turn over but doesnt. It has a pull start put it seems impossible to pull and have anything turn. Im not sure where to start other than making sure its getting power. I have it on a trickle charger for him and were gunna try in another day or so to rule out if its the battery or not. I feel like there is spark because the motor does something. but again i have no idea. he said he replaced spark plugs and bought a new battery and thats all that he tried. I hooked the battery up to his car battery with jumper cables and then tried to start the motor but again the same knock and tries to turn but wont keep turning over. Im guessing the solenoid or whatever it is, is the knock when it initiates the gear and then goes back down please help
 
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crandleman1

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Re: 1967 big twin evinrude wont crank

Does it sound like the starter and does is that what pops up and spins the flywheel?
 

Daviet

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Re: 1967 big twin evinrude wont crank

If you remove the spark plugs can you rotate the flywheel with your hands, the engine isn't locked up is it?
Have you checked for voltage to the starter, what type of voltage do you have?
 

crandleman1

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Re: 1967 big twin evinrude wont crank

I dont believe its locked up. He says it used to turn over and then he couldnt get it to fire. After he said he sprayed carb cleaner straight into the air intake around then was when this all started. I have not checked voltage to the starter. I really dont even know what the starter is, i think i do but not positive. i need a tester for the voltage but its my neighbors boat. Its in his garage so i will have to check at a later time on voltage. I will get back to you
 
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Daviet

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Re: 1967 big twin evinrude wont crank

Keep in touch, let us know what you find out.
 

crandleman1

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Re: 1967 big twin evinrude wont crank

ok so, I checked the voltage and the starter is getting atleast 7.5 volts when i turn the key and 13 at the battery i put the old spark plugs that he had replaced. After the old spark plugs were put in it turns over now. So problem voltage and bad starter are ruled out. Now i primed it and even tried shooting starting fluid in to see if it would fire and it wouldn't. So now I am convinced I have to take the carb off and I need to find out what i need to remove to get to the carb or if i can access the proper screws and nuts without removing the starter or flywheel or something.
 

Daviet

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Re: 1967 big twin evinrude wont crank

You should have more than 7.5 volts to the starter, check all the cable connections and make sure that they are clean and tight.
When you had the plugs out did you check the spark at the plug wires, it should jump a 1/4" air gap and be bright blue.
You shouldn't use starting fluid in the engine, it has no lube in it. Use a spray bottle with fuel mixture in it and spray directly into the carb.
 

crandleman1

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Re: 1967 big twin evinrude wont crank

how do i go about checking the spark at the plug wires? and no i didnt check im still learning. I will try that fuel mixture tomorrow and see what happens.
 

crandleman1

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Re: 1967 big twin evinrude wont crank

I think i understand how to check the plug and wire. I will unscrew the spark plug and replug it into the wire and place it near metal and see if there is an arc. I appreciate your help daviet. I am also going to clean up all connections after the battery that could be causing a lower voltage on the starter. Although, it seems to be cranking over at a sufficient pace(quickly).
 

Big Jay

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Re: 1967 big twin evinrude wont crank

Reading post #6, am I to understand the motor would not turn over with the new spark plugs in, but when the old ones were re-installed it would?

What plugs does he have? Old and new... Should be Champion J4C or J6C for that motor

Are the new plugs different from the old ones? Longer maybe?

Also, any idea when the carb was last fitted with a kit? Or at least cleaned?
 

jb93

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Re: 1967 big twin evinrude wont crank

Since this motor hasn't ran or ran right in some time, I would back up and start at the beginning. Check compression - if good then get a factory service manual and get after it. Required reading list below, and others as well using search. I restored a 1957 Evinrude 18 using this info...compression was good, rebuilt ignition system, cleaned and rebuilt carb, rebuilt lower unit, painted, runs. It was not that hard and I am no mechanic.

http://forums.iboats.com/johnson-evinrude-outboards/top-secret-file-updated-8-1-2012-a-299680.html

Reviving a Vintage Big Twin - Part 1
 

Big Jay

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Re: 1967 big twin evinrude wont crank

If the new plugs were long, it might be worth looking at the pistons ...
 

Daviet

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Re: 1967 big twin evinrude wont crank

Checking spark by using a spark plug grounded to the block is not an accurate way to do it.
You need to see if the spark will jump a 1/4" air gap and is bright blue. Either get a air gap tester from a auto parts store or stick a screwdriver in the plug connector and try and hold it a 1/4" from the block while someone cranks the engine over. Just remember that if you are holding onto the metal part of the screwdriver you will get shocked.
 

crandleman1

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Re: 1967 big twin evinrude wont crank

To BigJay- yes when i took out the plugs to see what was going on I noticed they were much longer. It seems to be that the piston must have been hitting it and that is why it wouldnt turn over. Once i put in the autolite spark plugs he had in the motor when he bought it back in it would turn over. both were autolite plugs just the new ones were way longer and he is upset at the guy who sold them to him. They actually got the boat in December, so 9 months ago. They guy who sold it to them was an old man and he said last year was the first year he hadnt taken it out so thats why he sold it in december. No idea of kit replacement on the carb. I wouldnt have any clue on how to check the pistons to see if anything was wrong.

To Jb93- Thanks for the links, Will be helpful. Im going to have to figure out how to check the compression. I will check your links here in a little bit. Im a little intimidated to start taking too much apart not having a clue and you're right, he needs to get a manual.


To Daviet- I will try the screwdriver tonight to see if there is even an arc at all. I hear anything with a magneto is a hell of a shock too. I will be careful.
 

Big Jay

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Re: 1967 big twin evinrude wont crank

Crandleman...

To check the pistons, shine a flashlight through each spark plug hole. Check for debris before rotating the flywheel any further, if clear of debris, you can then turn the flywheel slowly clock-wise. As each piston comes up, just closely inspect for any physical damage that may have occurred with the long plugs in (dings, scratches, holes).

If you see any metal particles or shavings remove them immediately, you don't want to score the cylinder walls...

I don't have any personal experience in this matter, but it's what I would do.... I'm thinking it's a possibility that the power from the starter likely rammed the piston into the plug, could've hurt something... maybe not... but maybe.
 

crandleman1

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Re: 1967 big twin evinrude wont crank

I shined my light in there when I was over there today and didnt see anything but empty holes but i didnt rotate it. I will check it out tomorrow. Today the spark plugs didnt spark and the screwdriver test worked good with a little blue arc. Did not work when i plugged the spark plug into the wire and put it on the block an few different ways where the screwdriver worked. I found a place here in my town that sells the champion J4C that will work for his motor.
 
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