Need advice on adjusting rich/lean setting johnson 18hp fd-18

[FD-18]

Getting good spark and engine starts and runs only if fuel is sprayed into carburetor. Have all new fuel and cleaned carburetor. The shaft for the low speed jet just keeps turning in place and cannot be removed. Need to adjust this correctly. It is the upper shaft that is connected to the RICH/LEAN knob, not sure what the lower shaft connected to knob does. Have tried a few times to remove upper shaft, but it just turns in place, seems stuck.

Engine is not getting fuel.

 

[kfa4303]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

Here you go FD-18. this should help. The upper needle is the "Low Speed" needle and is used to adjust and dial in the idle, while the lower needle is called the "Hi speed" and is used to adjust fuel delivery at speed. This link should help....

http://forums.iboats.com/showthread.php?t=167352

 

[FD-18]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

Here you go FD-18. this should help. The upper needle is the "Low Speed" needle and is used to adjust and dial in the idle, while the lower needle is called the "Hi speed" and is used to adjust fuel delivery at speed. This link should help....

http://forums.iboats.com/showthread.php?t=167352

Thanks, will check that link and work on carb tonight.

 

[FD-18]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

Any ideas on why the upper shaft just turns in place? Not sure if turning it is doing anything?

 

[lindy46]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

You obviously did not "clean" and rebuild the carb properly. If you did, you would have removed both low speed and high speed needles, removed the packing nuts, and cleaned the old packing out and replaced with new packing. If the needle is just slipping, you must first remove the packing nut, and the needle (with its' threaded bushing) should pull right out. The threaded bushing is just turning in the orifice. Once everything is clean, replace the bushing, insert new packing, tighten the packing nut and it will hold the bushing in place so it doesn't spin. Then you can insert the needle and it will properly thread into the bushing.

 

[FD-18]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

Is the packing nut the large nut at the front? The low speed needle is in the center of it. I'll try again to remove the needle after removing that packing nut. May be some crud in packing.

 

[cr9c1]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

What is happening is the needle bushing is just spinning instead of being held in place by the packing nut. What they're saying is to remove the packing nut, remove all the old packing washer material and bushing, then reseat the bushing, put new packing washers in, and tighten the packing nut. What is happening is the bushing is spinning because its not being held in place tight enough. Without being sure you installed the low speed parts correctly, you may have inadvertanly put the packing washers behind the bushing instead of in front where they belong, or not have tightened the nut enough to keep the bushing from spinning, or didn't get all the old material out so the bushing and new packing washers never seated correctly.

 

[FD-18]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

Thanks, I was able to remove everything, there were two packing washers in front of the bushing. I was not able to seat the jet even without the packing washers, the threads were not catching. Tried pushing hard, but could not get threads to start. Jet point was shiny and clean. The black packing washers were fine, very good fit. Problem is jet will not seat, just keeps spinning clockwise. I tried to find a service manual for FD-18, could only find the parts manual.

 

[FD-18]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

Problem seems to be low speed needle will not seat, metal threaded bushing may be incorrectly installed by previous owner.

Found these instructions for seating, but needle will not seat. Where can I get the rebuild kit for a Johnson FD-18 carb?

Screw in the bottom (high speed) needle until seated and then back out 1 turn.

Screw in the top (slow speed) needle untill seated and then back out 1.5 turns.

 

[cr9c1]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

The bushing doesn't thread into anything. It sits in the bottom of the carb, and the packing nut compresses the packing washers against it to hold it in place. The needle threads through the bushing, but the bushing just sits in there and is held in place by the packing nut. (At least, its this way on my 57. It may be different on yours but I'm not sure.) Can you remove the needle and bushing and take pictures of it and post them here so I can look and see what you are dealing with?

 

[FD-18]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

Here is the link to parts diagram. There is a threaded bushing behind the packing nuts.

http://www.marineengine.com/parts/v...ntage-evinrude-johnson/380047/38004700006.htm

 

[FD-18]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

The needle valve has to be threaded into something. It has threads at the back. but cannot get it to seat at all. Even without the packing nuts, needle valve will not seat or thread into anything.

 

[cr9c1]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

The bushing is threaded inside, but not on the outside. That looks like the same carb my 1957 18 uses. The bushing is kept from spinning by the packing nut. In my carb, the bushing goes in, then the packing washers, then the packing nut. It has to be relatively tight (but not super tight) to keep the bushing from spinning. The needle valve goes through the middle of the bushing and catches the threads in it. The needle valve doesn't actually thread into the carb, only the packing nut. The needle threads into the bushing, which is kept from spinning by the packing nut. The bottom half of the carb is different than mine, but the top half all looks the same.

 

[FD-18]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

Thanks, then the metal bushing with the threads inside must be the problem, it is frozen on the needle valve threads, not moving. I guess it should allow the needle valve to move through it. Will soak the bushing and needle valve for a while.

 

[cr9c1]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

Try some PB Blaster. Soak it. I usually use pliers and pull it out, if its stuck, but some may disagree with my methods.

 

[lindy46]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

Yup - just free up the needle valve to bushing threads so the needle valve turns freely in the bushing.

 

[FD-18]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

Thanks, took a while to figure this out, but now I see the needle valve is supposed to turn in and out through the bushing. Will soak it for a while.

 

[FD-18]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

Thanks, now have bushing turning freely, have ordered the carb kit with new packing washers. The bushing had a lot of chewed up packing material in the threads.

 

[cr9c1]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

My carb kit didn't come with a new nylon washer to put in front of the packing washers. Let me know if yours does. I was disappointed. They put them in there to keep the packing nut from destroying the packing washers.

 

[FD-18]

Re: Need advice on adjusting rich/lean setting johnson 18hp fd-18

Mine had the nylon nuts included, and two packing washers, instructions showed one packing washer and one nylon washer for the low speed jet.