Carb Low Speed Orifice

[mfwyatt]

I hope no one has asked this before. I did some searching but couldn't come up with anything. I have a 1985 Johnson 50 HP and I was rebuilding the carbs earlier. I disassembled the top carb, cleaned, then rebuilt it. Moved onto the lower carb. Once inside the lower carb, I removed the low speed orifice and it was clogged up. Not with dirt or grime. It looked as if someone took a bead of solder and clogged it up intentionally. The upper carb's low speed orifice was clear as a whistle. Why would someone have done this or is it possible it clogged up over time with metal shavings? I went ahead and cleaned it out. After I reinstalled both carbs, I had to turn my idle wayyyy down. I wasn't having any serious issues with the carbs before the rebuild, I just wanted to do it to see if it fixed any of the small issues I was experiencing.(engine was really cold to start, it would die out in reverse 85% of the time.) Engine seems to start really quick now, but want to see how it does once it hits the water.

 

[Craig-]

Re: Carb Low Speed Orifice

You did the right thing.

Should have 36 (std.) or 34 (long) on it, an idle orifice. It's an air bleed.
Closing down an air bleed would make the corresponding cylinder run rich.

I don't see it getting full of a metal substance on it's own.
Your main orifice behind the drain plug should be a 51D.

 

[mfwyatt]

Re: Carb Low Speed Orifice

good. I have never worked on anything with 2 carbs and I didn't know if the dual setup required one of them to be blocked off. My manual didn't say anything about it so I cleaned it out. I wish i would have taken a picture of it before I cleaned it. It looked as if it was soldered shut or jb weld. Thanks for the info. I'm hoping i can get it out on the water this evening to see how she does.

 

[mfwyatt]

Re: Carb Low Speed Orifice

How do I tell if I have a 34 or a 36? I may just need to buy a new one. I took it out tonight and it seems to start easier and reverse works a lot better but it will only idle for about 2 minutes then it dies. I wasn't able to get all of the substance out of the orifice so I'm hoping I can either heat it up and get the "solder" out of it or just buy a new one. Any suggestions?

 

[mfwyatt]

Re: Carb Low Speed Orifice

Also, I turned the idle adjustment back up quite a bit and it still dies out after a couple minutes.

 

[Craig-]

Re: Carb Low Speed Orifice

Number is on jet.
Try this link, you might want to rebuild them.
Did you get new kits on rebuild?
http://shop.evinrude.com/
Click on Johnson in scroll on upper left.

 

[Craig-]

Re: Carb Low Speed Orifice

Does pumping bulb keep it running?

 

[mfwyatt]

Re: Carb Low Speed Orifice

I did get new kits from Sierra. I will be taking it back out tomorrow with a buddy to play with the idle adjustment a little more. I'll try pumping the bulb. Would that tell me if the orifice is not letting enough fuel in?

 

[mfwyatt]

Re: Carb Low Speed Orifice

Ok, so I tried pumping the bulb to keep it idling once it started to die out. It didn't really make any difference, it still stalls. I turned the idle up 1.5 turns and it seems to keep the motor at idle but I'm sure its idling a little faster than what would be IDEAL. Think it would be best just to buy a new idle orifice for that carb? Thanks for all the help.

 

[Craig-]

Re: Carb Low Speed Orifice

Ok, so I tried pumping the bulb to keep it idling once it started to die out. It didn't really make any difference, it still stalls. I turned the idle up 1.5 turns and it seems to keep the motor at idle but I'm sure its idling a little faster than what would be IDEAL. Think it would be best just to buy a new idle orifice for that carb? Thanks for all the help.

It only costs a few bucks and might make all the difference if the original one was drilled and then filled. Give it a shot. You could even get both sizes and see if one works better than the other.

 

[mfwyatt]

Re: Carb Low Speed Orifice

So, when I pull the carb the idle orifice will say on it if it is a 34 or a 36 or is it listed somewhere else? Also, I guess I should check to see what the other carb has in it? Do the idle orifices need to be the same in both carbs?

 

[mfwyatt]

Re: Carb Low Speed Orifice

Well, I found out I have #36 idle orifices. $14/each....for a litttttle piece of brass. I figured I would have to buy a new one for the lower carb so I went ahead and pulled the orifice out and heated it up with a propane torch. It was most definitely plugged with solder! I managed to extract most of the solder with some copper wire. It appears to be very clean and it looks identical to the upper carb's orifice.(except it is silver colored instead of gold) I am going to be testing it on Saturday. Hopefully it is fixed. If not, guess i'll order the new one. Stay tuned for an update on Saturday!

 

[mfwyatt]

Re: Carb Low Speed Orifice

I am confused. I ended up taking the boat out for a spin today to test the work i did. It ran like crap. Wouldn't idle at all. No matter how much i turned the idle up, it would rev fast and then slowly die off. I made sure the carbs were in sync.(when the top butterfly is wide-open the bottom carb's butterfly is also) The only think I can think of, is that the PO intentionally plugged that idle orifice because he was having problems. I am seriously considering plugging that SOB back up with solder. UNLESS, anyone else has any suggestions for me. Just a list of things I have done recently. Cleaned and Rebuilt Carbs with new kits, rebuilt water pump with a new kit, installed new rectifier, raised motor up 1 hole on the transom. The only way I can get it to start is to raise the fast-idle lever on the controls and push the key down while cranking. Once it starts, I turn the fast-idle lever down a bit. If i push it all the way down, i either have to kick it in gear verrrry quick or just let it die. Please help. I'm out of my wits on this thing.

 

[mfwyatt]

Re: Carb Low Speed Orifice

anyone?

 

[SolingSailor]

Re: Carb Low Speed Orifice

Well, I think all the advice seems to be to get a new orifice.

$14 for a little piece of brass seems pretty cheap to not have to waste any more days fooling with it.

I'm sure you will have more response from the experts here once you follow their advice.

 

[Craig-]

Re: Carb Low Speed Orifice

Don't plug it up. Have you checked ignition? Spark test?

 

[mfwyatt]

Re: Carb Low Speed Orifice

Yes and its fine. spark jumps 7/16 gap.

 

[mfwyatt]

Re: Carb Low Speed Orifice

compression is 125 in both. spark plugs look great and jump a 7/16 gap. wiring harness is in great shape.

 

[Cofe]

Re: Carb Low Speed Orifice

I was looking at your idle jets for the carb. One says standard, and the others description is long.
If this was my motor I would try both. Here is a link

http://www.boats.net/parts/search/BRP/JOHNSON/1985/J50TELCOB 1985/CARBURETOR/parts.html

 

[mfwyatt]

Re: Carb Low Speed Orifice

HEY! Thanks. You found a website that has a cheaper price on the orifices. I am gonna play around with the throttle linkage today just to make sure i didn't miss something. If I can't get it going, I'll order one of each of the orifices. Thanks for the website.