detailed carb instructions

Joined
Jun 4, 2008
Messages
27
can anyone give me detailed instructions for rebuilding carbs on a "74 50hp johnson. i have sone instructions but they are a little vague and i just want specific instructions....mabey from a repair manual or something. i dont care about copyright infringements and sorry i am not buying a shop manual but the rebuild kits are on the way so any help will be much appreciated . thanks in advance !
 

ftltony

Petty Officer 2nd Class
Joined
Dec 21, 2007
Messages
117
Re: detailed carb instructions

They're not really that tricky and its mostly common sense.

There are a few things you need to be concerned with and those are the jets, the needle and the float. Along with the gaskets, its pretty much simple from there.

There is a post on this site that covers BASICALLY everything you need to do. I posted the link below. Go there, read it and give it your best shot.

REMEMBER, not every carb is the same so these instructions should be used as a "guide". For example, on some carbs, as described in the "carb rebuild link" below, it mentions you may need a "special" tool for removing your jets. On my carbs, I didn't need any special tool, I was able to use a regular screwdriver but everything else was basically the same.

http://forums.iboats.com/showthread.php?t=244013
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: detailed carb instructions

these instruction, are clearer than the manual, were taken from rebuilding 50 hp carb. the only difference is that your slow speed need is adjustable at the top center of the carb, you turn it out with your fingers, the high speed is as per instructions. when you reassemble the carbs with the kit. set you adjustable jet a 5/8 out from soft seated, and then adjust from there. per these instructions

(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.

Note: As a final double check setting of the slow speed valve(s), if the engine has more than one carburetor, do not attempt to gradually adjust all of the valves/carburetors at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve/carburetor. It may be necessary to back out "all" of the slow speed adjustable needle valves 1/8 turn before doing this final adjustment due to the fact that one of the valves might be initially set ever so slightly lean.

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.
 
Top