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1971 Johnson 85 carburetor slow idle needle "bearings"? Are there any?

M

Mark85

New member
I'm rebuilding the carbs on this engine. The Seloc manual shows a small white plastic seat they call a "bearing" on the tip of the slow idle needle adjustment. This bearing is included in the kit I have.

Since the day I owned it, it has been a little rough on a slow gradual acceleration, but smoothed out past a certain RPM, so I assumed it might be something in the low speed circuit of the carb. Got the rebuild kits and they have everything for many carb variations over the years. I've run this boat 25 years so I figured a complete rebuild is probably a good idea. When I took it apart, everything looked perfect, even the float needle valve shows no wear at all which was really surprising. Looked like it had just been rebuilt! So, probably dirt somewhere (some fine black powdery debris did come out of the various passages). I can't see a plastic needle "bearing" in the slow idle needle passage (but it's really hard to see down there). Someone suggested that a blunted wood screw could be used to thread into it and pull it out. Tried that very carefully, I could see the screw's thread marks on metal where it begins to taper, but nothing touched the orifice - no plastic needle bearing seems to be in the one passage I checked. Before I risk any further possible damage, did this particular carb have needle valve "bearings", or were they never installed when the last person did a rebuild?

I bought a set of used slow idle needles because the original ones in there showed quit a bit of asymmetrical wear at the tips which made me think they must be resting against something harder than plastic seats. If anyone knows the answer to this question, I'd appreciate sharing the knowledge as it is difficult to find information on a 50 year old engine! Thanks.

Also, what's the worst thing that could happen if I instal them? Wouldn't I still be able to adjust the needles to get a correct slow idle? I've worked on cars and motorcycle carbs, but I don't really understand what the needles do...I think they control the amount of gas sucked in at slow idle (or is it air restriction). I just blindly follow the manual, clean and replace parts and hope for the best! Thanks again.
 
Thanks for the reply. I think you are referring to the plastic retainers. Yes, 2 per needle. It's the bearing at the very tip where the orifice is that I'm wondering about. Not sure if my engine is supposed to have them
 
Thanks, I suppose their absence might explain why two of the needles were worn on one side. They were probably resting on the aluminum of the actual orifice. Maybe that's why it was running rough at slow speed - couldn't seal enough to prevent air from entering....sort of makes some sense. Thanks for getting back to me. I'll carry on with the rebuild tomorrow with the "bearings".
 
314166 Nylon Needle Valve Bearing... 2 per carburetor... 1 per needle valve!

The thing with those 314166 nylon bearings is............

If you don't remove them... and you soak the carbs in cleaner, that dissolves the bearing.
If you don't install them... that allows the needle valve tip to vibrate which wears a groove in the pointed needle portion whereas it's impossible to adjust them.
Best to remove and re-install.

Remove them by screwing a small 4-40 tap into them which is just large enough to gram the nylon but too small to cut thru them to grab the aluminum carburetor material. Pull straight out.

Install the new ones simply by installing it onto the needle valve, then screwing the needle valve into the carburetor.

Make absolutely sure that the old needle valve bearing isn't still in the carburetor when you install the new one, as if it is... and you screw another one in, it will be impossible to adjust it.

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Carb Adjustment procedure
(Dual Carb V/4 With 4 (2 each carb) Slow Speed Adjustable N/Valves)
(J. Reeves)


The adjustment procedure of the carburetor slow speed needle valves follows. NOTE... if the needle valves turn too freely, replace the nylon bearing retainer (the nylon item at the front of the carb that the needle valve goes through first) with the newer type RED retainer #315232. If your engine has that weird linkage that connects all four of those needle valves, the newer RED retainers will enable you to discard that linkage. The RED retainers make it impossible for the needle valves to vibrate out of adjustment.


(Carburetor Adjustment - 2 Slow Speed Adjustable Needle Valves, each carburetor)


Initial setting is: All (4) Slow speed valves = seat gently, then open 1-1/2 turns.


Facing the carburetors, start with the top left needle valve, then the top right valve, then the bottom let valve, then the bottom right valve. It may be necessary to redo these steps to get the adjustments ideally set


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.


Do not attempt to gradually adjust all four of the valves 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.


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.

********************
 
Joereeves: Thanks very much for the information. As is often the case a simple morning job is becoming complex and frustrating and I fight the impulse to grab some dynamite and cure it for good! If I get the light just right, I can look down that needle passage and I don't see any nylon bearings. I see metal that tapers slightly and I can see where my attempt to pull them with screw has caught the start of the taper. It looks like brass, but maybe it's just aluminum. So I came to the conclusion the last person to rebuild these over 25 years ago never installed them. Two of the needles were quite worn on one side as if resting on metal rather than nylon. I didn't soak these carbs assembled (because I learned my lesson screwing up a motorcycle carb). I did spray carb cleaner through all the passages I could and removed one welch plug -which was pointless because it was crystal clean underneath. I attempted to instal the new bearing on the needle, but the bearing would not move in far enough for the needle to grab the threads, so I couldn't screw the needle in to push the bearing down. When I pushed a little harder to try and reach the threads, I broke the bearing (cracked the nipple away from the collar) and had to remove it. I tried again on the other slow idle passage with a small drift to allow some collapsing of the bearing so that it could clear the threads, but it was a repeat failure. The kit bearing can not clear the passage's inner threads for the needle. I'm at a loss. I will put them together as is and maybe get another pair of nylon bearings to try later...will not be as easy as on the bench. So I am wondering if there are different diameters of nylon bearings or maybe I've got some variation of the normal carb. It seems that there were those with an orifice and no needle, and those with needles. I believe this is a Chinese carb kit, but everything looks absolutely identical to the OEM parts I'm replacing. Maybe the supplied bearings are incorrect? I'm going to gently try your tap method, but I'm 90% sure there is no nylon bearing in these passages. I'll let the forum know if I get some success. Probably other guys messing around with similar issues. Thanks again.
 
Can't seem to post images taken down passage. Trying but images don't seem to attach to post. Maybe it isn't possible? Anyway, I took some images and I can't see a nylon bearing down those passages. Was hoping to show the experienced eyes on here.
 
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Just a follow up to my needle bearing question: I had to take a day off work to go to the only shop in my city that deals with Johnson/Evinrude within their working hours. There was an old mechanic who said he has worked on these engines for abut 50 years (he seemed slightly indignant that I would question his advise). He told me that he never bothered putting those bearings in when he rebuilt those carbs back in the day because there was more than enough support for the needle with the threads and the plastic retainers and that the needle would do what it is supposed to do once seated correctly in the receiving seat of the orifice. We measured the diameter of their new OEM nylon needle bearings with vernier calipers and they were exactly the same diameter as the ones in my Chinese kit (the kits were probably made in the same factory). So there was no way they were going to be installed with success, and they couldn't see existing bearings at the ends of the needle passages with their inspection scope. So, I was told not to worry about it because they were never put in many years ago and my new needles would probably solve the problem of rough idle as 2 of the old ones were clearly worn ( I had pictures under a microscope of the needles to show them). I think I may be out of luck on this one and will have to be satisfied with that since the bearings supplied in the generic kit will not fit and are probably slightly larger and harder than those that were originally in the carb in 1971 (long since discarded by the guy who last rebuilt them 30 or so years ago). I've used that engine for 25 years with no needle bearings, but I suspect that likely did result in the wear on 2 needles. However, I now have another full set of good needles. Maybe that will be good enough for my slow idle issues for the next 25 years! If you have a similar engine with slow speed adjustment on needle jets, might be an idea to keep an eye open for some spare needles in case you come across this issue on a rebuild. I would not bother pulling the old ones up as you'll likely wreck them (or the orifice) in the process and then find you are unable to get the new ones installed without breaking them. One post I read somewhere stated that the mechanic never bothered with replacing them...probably good advise. I'm rewiring, repainting and replacing almost everything on this old engine. My boat (same vintage) currently has no transom, floor or stringers. It will be quite a while before I actually am able to test the engine at slow idle (possibly more than a year away). I will post the results when I'm eventually done. Thanks very much for trying to help me out! I appreciate it!
 
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