Carb trouble

[tphoyt]

Hi all it’s been awhile but I’m back on a new project.
I have an 87 J25rcur that’s running rich.
I have had the carb apart several times now and there is no passage that has not been cleared.
The only thing I have left to try is to try and get the nylon seat for the slow speed Neddle out and replace it. Any tips on how to get this out would be helpful. My plan now is to use a dental pick that I have ground down to fit in the valve chamber. I think it will work but thought I would ask for any other tips.
the motor does run but it won’t idle well and is clearly running rich. It’s smoking, the plugs are wet and it will cough back thru the carb from time to time.
Everything electronic on this motor is brand new as well as the fuel pump. Primer choke was rebuilt and is not passing fuel when it’s closed so I don’t know what else to do aside from replacing the carb which I have considered but I can find one.
Feel free to ask questions.

Thanks for reading
Tim

 

[Joe Reeves]

That small white nylon front taper bearing for the SS needle valve..... gently screw a small 4x41 tap into it. The threads of the tap will grab the bearing/bushing BUT will not go through it so as to touch the aluminum. Works for me.

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(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 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.

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[jakedaawg]

I'll just add that some of those carbs for a number of years had a float that could be installed upside down. If you end up with flooding issues check that. It's kind of counterintuitive just looking at it. Upside down kind of looks right.

 

[tphoyt]

Thanks for the tip and other info Joe.
I’ll give it a try.
Have a great Day
Tim

 

[Vibemanrts]

Sorry to jump into your topic but I am also running into a similar issue with a rough idle. Have discussed this back and forth with Willyclay and am not sure how to tell if the slow speed needle has that bushing or not. Seems we all have the same carb on our motors (Mine-J20CRCOS, WillyClay-J25RLCOS) and the parts breakdown that I can find does not show the white plastic bushing that comes in the carb rebuild kit.

1. Other than looking into the slow speed needle valve opening is there a way to tell if your carb should or should not have it? My eyes are not as good as they used to be!

2. I've looked on the intenet for a 4x41 tap and have come up empty. Can you paste a link as to where I can get one?

Thanks

Steve

 

[racerone]

better luck finding a 4-40 tap I think.

 

[Vibemanrts]

Racerone...Have one of those on order!

Thanks
Steve

 

[Joe Reeves]

Vibemanrts.... The J20CRCOS &-J25RLCOS does not have that bearing/bushing.

Tpholyt.... Yeah, sorry, 4x40 is what I meant. No idea how I typed that!

 

[Vibemanrts]

Thanks for the info!

 

[oldboat1]

http://ww2.iboats.com/Carburetor/dm/cart_id.059711324--session_id.202843207--view_id.1537714

I don’t see a nylon taper bearing for your carb, but maybe there is one in the carb you have installed. Did you get the domed expansion plug (#5) on tight (light tap)? Ideally, you will have checked in the top passage with the plug removed to make sure the opening is clear — to include no old needle point jammed in there.

Check out the float with post 3 in mind. You will be looking at the float bottom side with the carb top inverted.