66 Evinrude

66 6hp.Evinrude.
Starts and will run.But needs to have the choke pulled out to run????
Just replaced the float and the air screw gaskets.
Pumps fuel ok.
Pumps water good.
When running, the air screw makes very little difference other than to make it worse to idle.

Any ideas?

Re: 66 Evinrude

Check to make sure that the fuel pump diaphragm is okay as follows:

(Fuel Pump Diaphragm Test)
(Two Hose Type Only)
(J. Reeves)

Note: This pertains only to the regular Two Hose type fuel pumps.

Leave the hoses attached to the fuel pump. Remove only the two screws that attach the fuel pump to the powerhead. Re-insert those two screws and install a nut to each of them so that the fuel pump is securely clamped together. With the fuel line attached to the engine, pump the primer bulb while observing the pressure/vacuum operating hole on the back side of the fuel pump. Should any fuel leak out that hole, the diaphragm is faulty.

If the diaphragm is faulty, the fuel pump will require rebuilding or replacing. Note that repair kits are not available for all fuel pumps, in which case replacing the pump would be necessary.

If the fuel pump diaphragm is okay...... pump the fuel hose primer bulb constantly, acting as a manual fuel pump. If this corrects the problem, the fuel pump is faulty due to other reasons.

If pumping the fuel primer bulb makes no difference, you're overlooking something within the carburetor. If you didn't clean the high speed jet, do so with a piece of single strand steel wire. The jet is located in the "bottom center" portion of the float chamber behind that screw/bolt you see at the bottom front portion of the carburetor.

Re: 66 Evinrude

The idle mixture needle (air screw) only affects idle. That is the way it is supposed to be. A agree, check that high speed orifice in the carburetor bowl. DO NOT make it oversize while you are probing around with that wire. That will ruin it.

Re: 66 Evinrude

Thanks for the quick reply's.
The fuel pump/diaphram is Ok.I pulled the hose while it's running and it pumps great.
I'll take the carb apart again 5th or 6th time.
It won't idle unless the choke is out????
On Force/Chrysler and some others,The initial air screw setting is 1 turn out.What's the Evinrude air screw setting started at?
Back soon.THANKS AGAIN!!!!

Re: 66 Evinrude

(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.

Re: 66 Evinrude

The parts diagram I was using.Didn't show the jet in the bottom of the bowl.
Clogged!!!
Running great.
Thanks for the help.J

Re: 66 Evinrude

jerryjerry05 said:

The parts diagram I was using.Didn't show the jet in the bottom of the bowl.
Clogged!!!
Running great.
Thanks for the help.J

Click to expand...

Yay! Finally fixed one!

Re: 66 Evinrude

Thanks Joe.!!!!!!!!!!!!!!!!!!!!