78 25hp Johnson noise

I bought this motor for 50 bucks! Replaced the plugs and it fired right up but has a loud noise sounds like its coming from the flywheel. I doesn't sound like piston slap. I have a video on my phone but tapatalk doesn't let me post pics or videos!! Ill be at a computer on Monday but just wondering if anyone knew maybe from the description on what it is?

Hope this video works. I uploaded it from my phone someone please let me know if this works or not View My Video

Any help would be greatly appreciated. I'm going to buy a 14 ft tomorrow and would love to be on the water asap.

That sounds like an "external" rattle to me. Maybe part of the recoil starter? I would not have it idling quite that high unloaded. Drop the idle down to normal, and if it's still making the noise start pushing on the parts that should be stationary with your finger. My guess is when you push on the part causing the problem the noise will go away. Then you should find that a bolt, or a nut has vibrated loose.

That's what it sounds like to me is a nut or bolt just vibrating really bad. Ill double check when I get back in town. When u say unloaded do u mean not in the water? Sorry iv never messed with these outboards. And I found the idle screw at the end of this video.

[url=https://www.tinboats.net/forum/viewtopic.php?p=335601#p335601 said:

BeardedFisherman » Sat Nov 30, 2013 8:16 pm[/url]"]That's what it sounds like to me is a nut or bolt just vibrating really bad. Ill double check when I get back in town. When u say unloaded do u mean not in the water? Sorry iv never messed with these outboards. And I found the idle screw at the end of this video.

Click to expand...

Meaning throttling up with it in neutral and no resistance on the prop.

Gotcha

Difficult to assess where the noise coming from remotely. Couple of suggestions to isolate where the noise is coming from.

- Remove the manual starter on top, but leave the lower starter brackets on. You can then manual rope start the motor or use the electric starter. If the manual starter pawls/springs are damaged they may be rattling.

https://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1978&hp=25&model=25E78C&manufacturer=Johnson&section=Rewind+Starter

- Another thought, that someone was under the flywheel and did not properly line the charge coil (number 21) in the diagram link below. The flywheel may be rubbing up against the charge coil. This can cause damage to the flywheel magnets and the charge coil.

- Also look at the throttle linkages under and around the flywheel for being loose.

https://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1978&hp=25&model=25E78C&manufacturer=Johnson&section=Magneto


We assume that people or mechanics that do the work on the motor (prior to you owning the motor) knew what they were doing. That is not always the case. There are a lot of mechanics out there that do not know how to work on motors older than 20 years old.

**Look at the obvious stuff prior popping off the flywheel.

Cajun probably nailed it with the mis-located coil under the flywheel.
A quick visual check will verify this.
you can turn the flywheel by hand and watch the mag plate under the flywheel. If it looks like something is "grabbing" it and rotating it with the flywheel for part of the revolution then that is the issue. They will definitely make some racket if grossly mis-adjusted.
Also, in 1976 the Delrin ring that serves as the bearing and locator for the mag plate was made of a sub standard material and wore very quickly. If this is the issue the engine will never idle quite right and the mag plate can be moved side to side and up and down easily. This also can cause a noise at idle. If this is it simply replace with new.