Jump to content

Unofficial Home of Old Simplicity & Allis-Chalmers Garden Tractors

Need a carburetor opinion, maybe a carb expert


bkassulke

Recommended Posts

I'm working on a 23afb carb with the three bolt bowl. It is in a '64 landlord that I picked up. I know it isn't the original engine but it was a fresh rebuild. I didn't get the carb with it so I sourced one from a 23a I had sitting in my B1 . While getting all the necessary carb linkages found as it was missing quite a few I cross referenced part numbers in my "82 briggs engine manual so I know I have all the original style linkages for the carb. After rebuilding the carb, which entailed soaking in carb solvent and the works, i bolted it on the "64 and was amazed it started with out choke on the first rope pull.

 

That being the good part now we enter the real question here. I cannot get the engine to run past an idle for more than a second or two until it tries to die. It chokes itself out while smoking in the color black like a smoke tuned diesel. So i tried leaning out the main needle valve. I even tried an array of 9 different spark plugs 5 of which came from good running briggs engines. So I feel I have honestly tried about every adjustment I can think of. I even bought another carb kit, compared it to the original pieces and the pieces I had installed in the carb during the rebuild. I am at a loss. A carb has never given me this much of an issue. Which leads me here, does anyone have any ideas of what I am missing or maybe the carb is just a pile and I need to get another one. The thing is that it idles so well and I just hate to admit defeat by a chunk of metal that I am having a hard time convincing myself to go and buy a brand new one. I had also previous to installing the engine in the tractor checked the engine out for correct timing and checked the whole engine over as I have a hard time trusting the work anyone else that I don't know.

Thanks for the help guys

Link to comment
Share on other sites

Did you check float level?  If it is set too high, it can cause problems.  It sounds really rich to me...Especially if you can start it without choke.  I'd pull my jets, make sure the tips are CLEAN and the brass is complete (like the points are not broken off) and reset the idle to .75 turns out and the main to 1.5 turns out.   If its still rich,make sure the air filter is clean.

Have you checked condenser?  Maybe weak spark?  I know you said you checked the plugs, but plugs won't make a difference if the condenser isn't any good.   

Link to comment
Share on other sites

Is there any chance the carb you have has the opposite direction on the throttle lever? There are some that the governor rod  for some of our engines pulls the wrong way. I think our normal is down to open, up to close. Some three bolt carbs have the throttle plat arm for an opposite action.

That would cause it to possibley rich out and then quit?

I could be completely wrong here, just guessing.

 

Link to comment
Share on other sites

I had wondered about the float level being to high so I had tried setting it down to the point I could not get any fuel into the engine and than started working my way up until i could just get it to run. I have reset the main and idle jet i don't even know how many times. The spark on the engine is really strong. I adjusted the points and I have a strong purple/blue colored spark and it did get me once and it is one of the worst shocks I have had since I hit by a GM HEI spark at work. I haven't even put the air cleaner on yet since couldn't get the engine to run past idle yet. That should technically lean the mixture out.

On the throttle lever I guess I never even thought to check the direction of pull. I have the throttle from the tractor set to actuate the way the old briggs manual recomends for direction of actuation the way it is set up for the landlord. And the throttle lever which hooks to the governor arm is set up according to the my parts manual but I will verify, when I have time after work, that the operation is the way it needs to be. 

Thanks for the thoughts so far guys. This thing has me quite flustered.

Link to comment
Share on other sites

Float should be set level with the mounting surface of the upper carb half...In other words, flip the upper half upside down and set the float so that its parallel with the body.  

Link to comment
Share on other sites

I understand that the float needs to be set with the float parallel but since it seemed to be running too rich and I usually have to set carb floats slightly off of parallel due to ethanol being added to fuel. I played with the float setting to see if that had any bearing on the engine running issue. I know like on the quadrajet carbs I had worked on prior I had to keep the float level off of parallel to keep the float closing the needle at the correct time, due to the float setting different in the ethanol enriched fuel. When I first set the adjustment on the float with being level it leaked through the carb overflow and straight out the air cleaner elbow half. So i played with the float level until it didn't run any out, taking measurements as reference points to make sure that a float level change was actually changed.

Now for the throttle shaft. It orientated the same as what my briggs parts manual shows for orientation and it operates the same as my HB212, 212 variable, and B110 engine. Those being the three easiest to get to and check for similarities.

Link to comment
Share on other sites

sometimes the jets are backwards on carbs in that turning them out is leaning it and turning in richens. Not common tho. It does idle fine...it will sit and run good till you give it gas? Almost has to be the high speed jet. I wouldn't really buy a new carb as much as find a used one or a donner to try for troubleshooting. I had a big go round with the carb on an onan. It would flood out like what you are saying. I did buy a new one...played with float levels and cleaned it many times. It has an air filter housing that has 3 mount screws and also another hole for a breather...I had rotated the housing and was covering up the breather. Found that out by firing it up without the housing and it ran strong!!

Harry

Link to comment
Share on other sites

3 hours ago, bkassulke said:

I understand that the float needs to be set with the float parallel but since it seemed to be running too rich and I usually have to set carb floats slightly off of parallel due to ethanol being added to fuel. I played with the float setting to see if that had any bearing on the engine running issue. I know like on the quadrajet carbs I had worked on prior I had to keep the float level off of parallel to keep the float closing the needle at the correct time, due to the float setting different in the ethanol enriched fuel. When I first set the adjustment on the float with being level it leaked through the carb overflow and straight out the air cleaner elbow half. So i played with the float level until it didn't run any out, taking measurements as reference points to make sure that a float level change was actually changed.

The leaking through the air cleaner runner is common on these old briggs flo-jet carbs, and is not a sign that the float is too high.  The aluminum corrodes and the brass does not seal where circled.    Also, if it was taken apart previously from someone who didn't know what they were doing, it very possible the nozzle is broken.  It should extend into the Upper half of the carb.  A lot of the times, people will pull the top half off the bottom half and break the nozzle.  The proper way to disassemble (in case you need to know) is to remove the main jet needle and the nozzle, then pull the upper half off.  flojet_mainjet_leak.jpg

 

Neither of these will explain why its running rich though...I think linkages being backward might make more sense.  Do you have the governor springs on? Can you post a pic of the set-up?  That might help.

Hope I'm not insulting you with this information.  Its always hard to tell how much knowledge people on a forum have, so I always start with basics.  If you've messed around with quadra-junk, these carbs should be a piece of cake!  

Also, look up ZippoVarga on Youtube.  He has a whole series of carb videos on these old engines.  I think there is a four part series that will walk you right through the whole set-up.  From what I remember, different years and styles of engines had the throttle cable attached slightly differently.  That might be part of the issue too...

 

 

Edited by Mike_H
Link to comment
Share on other sites

If it was running that rich you would likely be seeing fuel flowing out the bottom of the carb.  I agree though that if it is putting out black smoke it is a sign of running rich.

The float could be sticking or the float needle and seat may not be a correct match.  The rebuild kits for these old carbs often give extra parts to accommodate carbs without a replaceable seat and if the wrong needle was put in it may not be closing off the fuel or it may never be closing the fuel regardless of float position.

I believe for carbs with non-replaceable seats you use the solid metal needle.  If using a brass seat you use the needle with the rubber tip.

A properly running engine should not need the choke on to start in warm weather especially if the float bowl is full of fuel so it does not have to work to pull any in.
Also, set your idle screw a little higher while troubleshooting the carb adjustments so you know it should be getting enough fuel past firing up.

Verify you have no leaks around the gaskets and that your throttle shaft is not overly worn and sucking/blowing air/fuel out the side of the carb.
 

Link to comment
Share on other sites

Mike-H said  "Neither of these will explain why its running rich though"

 Mike, To my understanding, If the shoulder on the nozzle is not seating properly, These carbs will run rich. The fuel is allowed to stand in the bore and bypass the jet adjustment when vacuum is present. Fuel will also sometimes leak from the small holes in the nozzle while not running because they are so close to the fuel level in the bowl. (Leading people to sometimes think there is a crack in the bowl or some such because the needle and seat seem to be fine)

 Many times I have found these older carbs to have dirty (oxidized) and or fouled threads where the nozzle installs making it hard to tell / feel when the nozzle is seated. A q-tip with a little polishing compound on it works cleaning the inlet seat as well as the seat for the nozzle BTW.

 As I said, this is the way I remember things and it is possible that I am mistaken. 

  • Like 1
Link to comment
Share on other sites

Use caution on tightening the nozzle to assure proper seating...brass threads and screw slots are VERY easy to strip. Be sure to use the exact size blade on the driver to match the slot on the nozzle or you will end up having to drill it out to get it removed....don't ask me how I know this!9_9

Link to comment
Share on other sites

11 hours ago, Tarheel said:

Mike-H said  "Neither of these will explain why its running rich though"

 Mike, To my understanding, If the shoulder on the nozzle is not seating properly, These carbs will run rich. The fuel is allowed to stand in the bore and bypass the jet adjustment when vacuum is present. Fuel will also sometimes leak from the small holes in the nozzle while not running because they are so close to the fuel level in the bowl. (Leading people to sometimes think there is a crack in the bowl or some such because the needle and seat seem to be fine)

 

That makes sense...If it can leak one way, it sure can leak the other! :)

Link to comment
Share on other sites

  • 2 weeks later...

Well after finally being able to get a good chunk of time to mess with this tractor after all my work and life obligations were fulfilled... SHE RUNS and yes I meant to yell  that... I checked spark once and still had a spark that would jump a 3/8ths gap from the plug wire to the head when I tried to throttle it up I left the spark system alone. I still don't know exactly what was wrong but I can get it to throttle up all the way to 3600rpm with out a stutter, it does not leak any fuel out of the carb and I couldn't be any happier. My guess is something was stuck in the carb or my patience just had to be tested to its limits. I would figure that I took the carb on and off about 50 plus time and apart near as many times. But for a 50 dollar investment on a tractor and freshly rebuilt engine, I guess I could take time to make another one run to get the satisfaction of saving something that would have been parted out otherwise. Now for the finishing touches on the ol '64 Landlord. She won't be pretty when I'm done since she will have some allis colored parts on her but she will work.  Eventually the pics are to follow of before and after on the old girl. 

Thank you gentleman for any and all insights. And as I said I don't know exactly why it works now but I will chalk it up to a win to make me feel better :)

Link to comment
Share on other sites

  • 2 weeks later...

Well, I have a 16 HP I/C engine that I bought because I could not make it run to satisfy the owner. I just bought the whole dang mower! I had carb issues, but. The man was a maintenance mechanic at a local plant. The governor inside the engine had failed, so I put a new one in. He had removed all the linkage and was controlling with the throttle lever. Not sure how that worked... Anyway, took care of that, bought a bunch of linkage, started it up, idled fine, started to speed up..and about half throttle, died., and it was consistent, it did it every time! So, the carburetor was next, though he had assured me that he had never had it apart. Someone had. The emulsion tube was cut so that the end just cleared the throat on the low side, above half throttle, it choked out. Put a new one in, and I have a fine running 16 HP I/C engine

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...