Major problems with my carb, on my 25 HP 72; Johnson

[miketer]

Hello

I'm new here, and I have some major issues I need help with.

first let me explain totally what is going on and what I have done.

I first of all just rebuilt my Carb because of poor performance. I use an original Carb rebuild kit I also replaced the Slow speed needle.

Here is my first problem the motor will only run with the choke closed all the way, and dies when the chock is opened. Now if i turn the slow speed needle all the way out many turns away from the initial 1 and 1/2 turn setting I am able to run the motor with out the chock but it dies as soon as the speed is increased.
Now today I checked all hose connections, and gaskets, as well as the fuel pump, and all lines for leaks thinking that an air leak is making the chock over compensate. I found nothing.

Now here is the real puzzle. As meticulous as I am when I put the carb apart I also removed the core plugs. when I did this I replaced them however I don't remember if I removed three plugs or two. The reason I ask this is because I put three back in and ON plug over a hole that is in the inside of the carb under the float valve but I'm not sure if I was suppose to do this. The kit came with four plugs so I assume the kit is for other carbs.

Now the exploded view in the original parts manual shows no plug going inside the carb body under the float. What I need to know is if anyone knows if there are more then 3 core plugs on my carb, or if there is in fact a plug that goes in the hole under the float.

i have attached some pics of my carb.

I did adjust the float tonight, and that improved the idle at low speed but I still had to keep the chock on.

so Here is my question what is the most common place for a leak on these things, and or why is the carb trying to compensate for the rich mixture. I'm at a loss and I really want to get this boat out on the water this year at least once. Help!!!

 

[miketer]

Re: Major problems with my carb, on my 25 HP 72; Johnson

how do people get help on this forum?

 

[tashasdaddy]

Re: Major problems with my carb, on my 25 HP 72; Johnson

Welcome to iboats forums.
First you posted rather late in the evening. this is not a chat room. patience, and waiting for someone to come on that knows the answer to your question. would you rather have a guess. the core plug does not belong there, remove it, should solve your problems.

 

[miketer]

Re: Major problems with my carb, on my 25 HP 72; Johnson

I apologize for my last post. I was not trying to be rude. I'm just very very frustrated, but it was uncalled for.

thank you for you reply...

So you think that core plug does not belong there?

I will remove it and try that.. and get back with you guys.

Mike

 

[miketer]

Re: Major problems with my carb, on my 25 HP 72; Johnson

sorry to double post, however, that port (hole) in my picture looks like it was made to receive a plug. If i remove that plug and it runs worse than I will have to order a rebuild kit because that is were I got the plug to begin with and since there is not part for it in the original manual I will not know what to ask for... so I will waste money on a whole rebuild kit if it does not work without the plug.

just another thought.

Mike

 

[14ftgrumman]

Re: Major problems with my carb, on my 25 HP 72; Johnson

What's that screendoor spring for in the first picture- I've got 2 of these motors and no spring like that.

 

[bktheking]

Re: Major problems with my carb, on my 25 HP 72; Johnson

TD is correct, I was going to post the same thing yesterday afternoon as it does not appear in the parts breakdown on shop.evinrude.com. The kit you purchased was probably a multi carb kit which has multiple core plugs for different carbs. As a rule of thumb and idea for you in the future that I have found to be more than helpful in the past is a digital camera, if you are working on something new and have a terrible memory like me until you've done it 5 times, take pictures before you start pulling things apart.

 

[Joe Reeves]

Re: Major problems with my carb, on my 25 HP 72; Johnson

The engine runs only with the choke on? Fuel must flow freely thru the high speed jet located in the center portion of the float chamber before it can gain access to any other fuel passageway.

Clean that jet with a piece of single strand steel wire.

(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.

Note 1: 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.

Note 2: If the engine should be a three (3) cylinder engine with three (3) carburetors, start the adjustment sequence with the center carburetor.

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.