Where can I download a free manual for Evinrude 4HP motor.

Try this site.

https://www.manualslib.com/

https://www.ebay.com/itm/1971-4-hp-Johnson-Outboard-Motor-Repair-Service-Manual-Evinrude-4hp-/192360652417

the smaller one is for idle speed, the larger is adjusted at high speed to highest rpm and smoothest running. high speed and low speed jets. High speed is on top and is adjusted at full throttle.

the side of the motor has a wiring diagram, pictures also help us fixya guys help u

My E4RCCS 1988 outboard has a diagram at the fuel inlet that says 100:1 fuel mixture

the problem with the sound is the bearings inside the motor are going out. i have the same pump and i have to replace the motor. replacing the bearings is very hard and will cost you about the same after you carry the motor and new bearings to a shop to be pressed in. hope this helps!!

C. MOTOR HUMS, BUT DOES NOT START—
Check for:
1. Centrifugal switch stuck in open position.or if capacitator start could be bad capacitator. Possible loose connection.
2. Binding of motor shaft. (something stuck in impeller) Does motor turn free. IF not check for jamed impeller. If it she sp2605x7 you can view a manual here:
http://www.haywardnet.com/products/Manuals/pdfs/manual113.pdf

You should have a High Speed carb adjust and a Low Speed carb adjust. If it's running fine while idling, adjust the high speed setting. If you have two nobs, its the lower one. May be set wrong. If you don't have two nobs, remove the carburator and check the jets to make sure they are completely clean or better yet, order yourself a carb rebuild kit to take care of all of this. I just rebuilt my 1971 evinrude 4hp and the carb kit made the world of difference.

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/matthew_d24b835e574ef6ca

Open the fuel valve ( at the back near the spark plugs).
Pull the choke knob ( SB side at the lower front of the motor)
Set the throttle handle in 'start' position ( abour 1/4 of the travelling way from SB to Port)
Pull the rope starter.
Should start easily.

Try this link and see if you can find what you are looking for. Hope this helped and best wishes.
http://www.marineengine.com/parts/parts.php

the proper mix is 50 to 1 or 16 oz to every 6 gallons,in my little boat I put 4 quarts in the 48 gal tank and its been running for 22 years,your running way to rich and your plug is probaly fouled,take it out clean it up/dump your fuel and mix it right,thats a great motor you got,I hunted with it for years,oh yeah when you get started run it till all the smoke is gone or you will have carb problems ,if you dont have them all ready,a little carb cleaner wont hurt but get it running first,or all that trash will foul you out,have a great trip bartriley1