Running rich

[zz28zz]

Getting closer to getting my 1987 Elite 50 running. Found my float level is too high. It's not high enough to come out overflow tube, but too high to run right. Float is plastic and not adjustable. Don't see anything wrong with the float, no holes/leaks Already replaced float "needle" and polished the "seat". It shuts off ok, just the fuel level is too high. Is there an adjustable brass float available?

Also discovered my mixture screw spring is missing. Screw wants to turn itself in while running. Are these springs available anywhere?

Thx!

[zz28zz]

No luck finding an adjustable float so ordered a direct replacement (and another needle valve). Hopefully it floats better. Not 100% I have the correct needle installed. Maybe it's just a little too short??

Still looking for a spring. Don't really want to order a whole carb just to rob a little spring off of it.

[zz28zz]

Still still trying to figure out why eng runs so rich. Starting to think fuel bowl level is OK and bystarter may the the issue. Did a test where a vacuum pump is attached to the bystarter air inlet. Once bystarter warms-up the air is shut off. Did same test to see if the fuel is being shut-off but appears it's not. Starting to wonder if I have the correct bystarter installed. Were there different diameters/lengths of the bystarter "needle" (portion that's supposed to shut off bystarter fuel)?

[motormike]

Still still trying to figure out why eng runs so rich.
Starting to think fuel bowl level is OK and bystarter may the the issue. Float level is probably okay, agreed.
Did a test where a vacuum pump is attached to the bystarter air inlet. Can you show us a pic of where you have attached the vac. pump hose?
Once bystarter warms-up the air is shut off. Sounds good
Did same test to see if the fuel is being shut-off but appears it's not. Confused here as to where you connected the vac hose ?
Starting to wonder if I have the correct bystarter installed.Me too...sounds like it is wrong
Were there different diameters/lengths of the bystarter "needle" (portion that's supposed to shut off bystarter fuel)?No question that dif carbs will have dif length needles.

[bonesv]

So I am going to assume this is an original honda carburetor that is for the motor you have? Not some "other" carb from "another" scooter? Perhaps you have mixed in some other non-original parts not for that particular carb? Just want to be straight on all this before we assume everything. Check needle clip position. Bottom position is richer-top position is leaner. Are you sure the petc ock is not stuck open? Lines are not leaking or cracked?
Question: How did you figure out the float level was too high? Which method did you use? I have small springs for A/F screw if you want to send me a PM with your info, I will be happy to send one. I assume the model scooter is the SE50? Or is it the SB50?

[zz28zz]

Bonesv;

Sorry abt the delay responding. It's been a busy holiday season. I bought the scooter from a kid who had been working on it for a while apparently trying to get it running. No idea what he may have swapped out. Scooter is a SE50P.

I had prev dropped the needle down as far as it can adjust with the clip in an effort to lean it out. No help at all.
I was checking fuel bowl level by attaching a clear fuel line to the bowl drain and opening the valve. Had fuel line run up next to carb. I also have a manual vac pump attached to the petcock so I can open or close the petcock at will.. If I allow the bowl to fill, it fills up to the top of the bowl then shuts off. Does not leak out of overflow hose. When started with a full bowl, I can hold it wide open and RPMs stay low, eng is barely running and back tire is barely spinning. Lots of smoke. If I shut off the fuel petcock while holding throttle wide open, after fuel level drops down to abt 3/4 full, it starts running good and I have to allow throttle to close to prevent over-revving. Smoke decreases also. Running pre-mix currently at 40:1. Oil pump is disconnected and vac port plugged.

Another thing I noticed after I replaced all the fuel lines (with translucent type) is that the vac line that goes to petcock has fuel bouncing around in it but the fuel is not coming from the petcock. It's somehow getting blown into the line from the intake port. Maybe this is normal for a 2-stroke with vac actuated petcock?? Thought maybe the reed valves were leaking but they look OK.

It also doesn't want to idle. I have the idle speed screw turned all the way in. It runs better with idle mixture screw backed waay out. Actually it runs even better (but still not right) if I completely remove the mixture screw.

This is why I assumed the fuel bowl level was too high.

Now the bystarter is on the top of my list of suspects. I was able to confirm the air is getting shut-off after bystarter warms-up using test procedure found on this site (uses cone shaped adapter on vac line of hand pump inserted into the Air inlet for bystarter). I tested the bystarter fuel circuit by connecting a manual vac pump to the fuel pick-up tube (that has it's own well incorporated into the fuel bowl). I did notice this fuel pick-up tube has a couple of holes drilled into it close to the top of tube. I taped those holes to test if bystarter fuel circuit being shut off. I wasn't able to produce any vac with pump connected this way so I'm assuming the bystarter is not shutting off the fuel.

I'll send a you a PM in regards to the spring. THX!!

[Bear45-70]

What main jet are you running because too big a jet will cause a rich condition.

[zz28zz]

Not sure on main jet size but doubt that's the issue since it won't idle. Main jet is mainly for WOT (but also plays a part at 1/2 and 3/4 throttle).

[Bear45-70]

Then have you tried backing off the Idle needle so it will idle properly.

[zz28zz]

Idle mixture screw/needle has been adjusted from fully closed to completely removed. Runs best (but still very poor) with it completely removed.
Idle speed adj is all the way IN.

Installing or removing air filter box makes little to no difference.

The only time it seems like it might want to idle is when fuel has been shut off at petcock and fuel bowl level is abt 1/2 to 3/4 full.

Need to fugure out what bystarter I need to match the carb I currently have installed (SE50 carb I think). Not sure if the SE50 and SE50P use the same bystarter.

[bonesv]

After reading your last 2 posts, I too, tend to think the jetting is too big either in both circuits or possibly you have a drilled out jet. I have seen that before-where someone will try to richen up the mixture because of an air leak somewhere or lack of an oem air box drill out a jet. Just say'in. Everything you mentioned caused me to believe that your carburetor is running rich. It could be some other explaination but that was my first thought. One other thing-if your exhaust pipe is full of soot, oil residue or just plugged up somehow-It seems like that is also a possibility and would be displaying the similar symptoms as you have now. Look into pulling that pipe unless it's brand new, and try to verify it's not plugged by something. I bet you can find the problem and then let us know what it was!

[zz28zz]

Went looking for a new bystarter and found that a new carb is only a few bucks more.

Ordered the Amazon carb. If it works OK, I can use it for stare & compare. Ideally, I'd like to have the "orig" carb working right.

I blew thru the exh pipe when it was off with 120 psi, no restrictions.

[motormike]

following...because I want to know how buying a Chinese POS carburetor works out for you.

[zz28zz]

To be honest, I'm not really expecting the Chinese carb to work all that well. More of a troubleshooting endeavor than a "fix". New carb arrived yesterday. I'll probably be tinkering with it this weekend.

[zz28zz]

Got the new $22 China carb installed. I was a bit lazy and re-used the orig main needle/slide assy. Used my hand vac pump to open the fuel petcock then hit the starter button and walla, it started immediately and idled nicely. Let it warm-up and never had to touch the throttle. After abt 1 min of high idle, it dropped down to a normal idle. Made a couple of minor adjs to the idle speed and mixture screws. I was amazed it started and idled so well.

Took it for a spin around the block. Only issue was after running WOT, chopping throttle to let it slow, then rolling the throttle back ON, it would hesitate a bit. Remembered the needle clip was still set to leanest position. Instead of moving the clip back to middle position, decided just to switch over to the new needle/slide assy that came with the new carb. (Clip was already set to the middle groove) Now it doesn't want to start. Once I did get it started, it wouldn't idle. Adjusted idle mixture and speed screws, no help. Put my orig needle/slide assy back on (moved needle clip to middle position), and it's running good again.

I've been using a jump starter pack to start it since the main batt is beyond dead. Think it's now worthy of a new battery. Will look for a new battery and a couple of bolts today to replace the bolts I robbed from other parts of the bike to mount new carb.