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Tan
Tan, MerCruiser Certified Technician
Category: Boat
Satisfied Customers: 10632
Experience:  40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.
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I have a 1956 15hp evinrude twin that has no spark. I noted

Customer Question

I have a 1956 15hp evinrude twin that has no spark. I noted that the coils were cracked and points were pitted. So I replaced both coils and points and still have no spark. I'm wondering if I've connected the spark wires correctly to the coils. It appeared that the wires just were threaded into the port under the coils. The spark wires have continuity. Is there any help you can give me as to what my problem is?
JA: Sometimes things that you think will be really complicated end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Is there anything else the Marine Mechanic should be aware of?
Customer: Not that I'm aware of. THANKS for your help!
Submitted: 3 months ago.
Category: Boat
Expert:  Tan replied 3 months ago.

Hello, I'm Tan. Welcome to JustAnswer. I'm reviewing your question and will reply momentarily.

Expert:  Tan replied 3 months ago.

Did you disconnect the stop switch use to turn the engine off? If not disconnect it and check spark.

Customer: replied 3 months ago.
THANKS for responding, Tan. This engine has that control on it's handle. To the best of my knowledge, there is no "OFF" switch. The handle label says: STOP, SLOW, SHIFT, START, then a longer space and finally FAST. Each time I tested for spark, I have turned the handle to START. On the rotating plate that holds the coils, points, condenser and spark wires underneath, there are machining marks which are aligning marks for the positioning of the coil's armature ends and I've taken pains to get them aligned. And the magnets in the flywheel will easily hold a section of a hacksaw blade. This rotating plate has an eccentric bracket that controls the throttle and this bracket ends just after slow, so I know that the throttle is well closed by the time the handle is turned to STOP. I'm stumped, that's why I called for help.
Expert:  Tan replied 3 months ago.

What do you have the points gaped at?

Customer: replied 3 months ago.
It says on the flywheel .020.
Expert:  Tan replied 3 months ago.

You should have 2 wires coming from under the flywheel with quick dosconnects. Disconnect one of those wires. Check for spark.

Customer: replied 3 months ago.
No, Tan. I don`t have ANY wires coming out under the flywheel. The only wires coming out under the flywheel are the spark plug wires.
Expert:  Tan replied 3 months ago.

Did you replace the spark plug wire? Just because they have continuity that doesn't mean they can't have holes or breaks in the insulation for spark to go to ground instead of firing the spark plug.

How are you checking for spark?

Customer: replied 3 months ago.
No, that's the only part of this system that I haven't replaced. (Remember this is a 2 cylinder, so 2 of everything.) I'm checking for spark by using a simulated spark plug with an alligator clip fastened to one of the flats of the hex and the usual grounding strip of metal on the bottom removed. My dad had an automotive repair shop years ago and this is one of the things I kept when he sold his business. In other words, the gap on this tester is from the center electrode to the metal side of the plug, much more than the normal plug gap of .030. But I've used it on other pieces of small engine repairs with success. Got a better way of testing or is this OK?
Expert:  Tan replied 3 months ago.

Ok when the ignition system is working correctly it should jump a 3/8 gap when using a spark gap tester with adjustable gap. So your tester will verify spark just not how strong the spark is. Spark always wants to take the shortest path to ground. So if the plugs wires are old and the insulation isn't that good it will spark to ground where there is no resistance before it will spark at the tester.

Now just by process of elimination that is the only thing left that you haven't replaced. With everything new you should have good spark.

Does this make sense?

Customer: replied 3 months ago.
Sure. Now give me some time to get some new S P wires. I would assume I could just buy an automotive set and make them fit. Am I correct? How about you give me until Monday before I get back to you.
Expert:  Tan replied 3 months ago.

Only if they have a solid wire core conductor. There are no time limits take as much time as you need.

Customer: replied 3 months ago.
TAN: I'd prefer to wait until after I have installed the new S P wires to see if your advise is correct. They will arrive on Friday 10/28.
Expert:  Tan replied 3 months ago.

Ok no problem. You are still going to be charged. Rating only gives me credit for helping you.

Customer: replied 2 months ago.
I`'ve replaced the S. P. Wires with solid core wires, but to no avail as I still have no spark! I wonder if there is a ground wire missing. Since the platform that holds the coils, points & condenser rotates around the top of crankshaft, I`m wondering if there is no ground in this system. The motor`s control arm is connected to this platform by a slip joint, but it sure is not a good ground. What`s your opinion?
Expert:  Tan replied 2 months ago.

Run a jumper wire from the plate to the engine.

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