58' Evinrude 18hp fast-twin

[G-loomis]

Hi I have bought this older motor a month ago and need some help, I am having trouble with the carb adjustments both are turned in all the way, the carb leaks gas like crazy when I prime the double line steel pressure tank I know it runs great when I bought it, I just put new plugs in, It back fires when I try to start it. there was black gunk coming out of the back of the motor when it ran, so I changed the gear case oil.

Thanks for any help.
BRAD

 

[Joe Reeves]

Re: 58' Evinrude 18hp fast-twin

Purchase a carburetor kit at this site if it's available, or at your dealership, or NAPA. Purchase a service manual at this site if one is needed and/or available.

Remove, clean, and rebuild the carburetor. Use Champion J4C or J6C spark plugs gapped at .030. The J6C plugs may provide improved performance.

(Carburetor Float Setting)
(J. Reeves)

With the carburetor body held upside down, the float being viewed from the side, adjust the float so that the free end of the float (the end opposite the hinge pin) is ever so slightly higher (just ever so slightly off level) than the other end. And when viewed from the end, make sure it is not cocked.

(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:

NOTE: For engines that DO NOT have a shift selection, obviously there is no NEUTRAL position. Simply lower the rpms to the lowest setting to obtain the low speed needle valve adjustment.

(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.

http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store

 

[G-loomis]

Re: 58' Evinrude 18hp fast-twin

Joe Reeves: thanks for the info, I have taken the carburator apart once already I am thinking that the cork float is no good anymore and needs a new one, just wondering a carb kit is ??? and where on this site may I find one.

Thanks
BRAD,

 

[kkirsch]

Re: 58' Evinrude 18hp fast-twin

Have a similiar problem. The solution is either a new float or go to the local hobby shop and pick up some clear airplane dope. Allow the carb float to dry really well and may be good to soak and dry in lacquer thinner or carb cleaner to thoroughly clean it. Then apply 3 coats of dope to the float. That will bring it back to life. Also: check the fuel lines from the sediment bowl to the carb. They may be plugged or restricted. Finally check the filter in the bowl. put in Lacquer Thinner or Acetone over night then blow out with compressed air. If none of that helps work your way back to the tank checking the tank for sediment or bad gas.