Old Evinrude info

skynyrdcat

Petty Officer 2nd Class
Joined
Mar 11, 2007
Messages
157
A friend asked me to take a look at his old (approx 1968) 33 hp OB.

He can't get WOT (BOGS DOWN).

I've not looked at it yet and have never worked on a motor that old (and have no manual for it).
My first thoughts are carb or maybe points, compression...

Anyone got any links to specs for these older engines (point gaps, ignition ohms tests, compression etc)?


Again, I have not looked at it yet, but when I do I can post the model numbers (if needed).

Thanks in advance.
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: Old Evinrude info

Compression should be approximately 100+ psi and even on both cylinders. Is it?

With spark plugs removed, the spark should jump a 1/4" gap with a strong blue lightning like flame...... a real SNAP! Does it?

If the above is okay, suspect that the carburetor is fouled, gummed, clogged. Remove, clean, and rebuild it using a complete carburetot kit.

Depending on which carburetor that engine might have, use one of the following methods to adjust it.

(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.

--------------------------------------------------
(Carburetor Adjustments - Two Adjustable N/Vs)
(J. Reeves)

Initial settings are: Bottom high speed = seat gently, then open 1 turn out. Top slow speed = seat gently, then open 1-1/2 turns.

Setting the high and low needle valves properly:

(High Speed) Start engine (it will run pretty rough), shift into forward gear, take up to full throttle. In segments of 1/8 turn, waiting for the engine to respond between turns, start turning in the bottom high speed needle valve. You'll reach a point whereas the engine will either start to die out or spit back (sounds like a mild backfire). At that point, back out the needle valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest setting.

(Low Speed) Slow the engine down to where it just stays running. Shift into neutral. Again in segments of 1/8 turns, start to turn the top needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running. Eventually you'll hit the point where the engine wants to die out or it will spit back. Again, at that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

When you have finished the above adjustments, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
 

skynyrdcat

Petty Officer 2nd Class
Joined
Mar 11, 2007
Messages
157
Re: Old Evinrude info

Thanks Joe (very good info).
I expect him to bring it by this afternoon, but it may be later in the week.

I'll keep you posted.
 
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