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Post by billw129 on Mar 4, 2011 21:28:08 GMT -5
Ok so got the new motor in and it runs like crap. It starts right up and idles a little bit rough but when you give it any throttle it bogs right down. If you feather the throttle it will come up to somewhat speed but not really. I took the air box off and it runs a little bit better but not anywhere near good. Try to adjust the carb and it only runs decent with the screw out about a half a turn. it was at 1 1/4 stock. any help would be great.
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Post by 90GTVert on Mar 4, 2011 21:29:35 GMT -5
Sounds like it's running rich. How does the spark plug look? What main jet is in there?
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Post by billw129 on Mar 4, 2011 21:32:40 GMT -5
is it possible that the 50cc pipe is causing this?
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Post by 90GTVert on Mar 4, 2011 21:34:37 GMT -5
That wouldn't be the first place I'd look. The fact that it improves when you remove the air filter is telling you it's rich.
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Post by billw129 on Mar 4, 2011 21:35:56 GMT -5
ok so excuse me for being an idiot but what steps should i take for a rich condition?
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Post by 90GTVert on Mar 4, 2011 21:42:29 GMT -5
For what you've described, I would adjust the idle mixture first to straighten the idle out a bit. Turn the mixture screw about 1/8 turn at a time and give the engine a second to catch up. Find the setting that will give you the highest idle, then adjust the idle speed if necessary with the idle speed screw. If you can't even get to WOT without bogging and stumbling, try a smaller main jet. Continue to adjust main jet size until you get the best performance at WOT with the filter intact. I use RPM and speed over a given distance to tell the best performance. To stay on the safer side, you might wanna go 1 step up from the jet that gives best performance. Once that's straight, then you can try to adjust needle position to straighten out part throttle, and then make sure the idle mix is still set as described earlier.
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Post by 90GTVert on Mar 4, 2011 21:45:59 GMT -5
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dr1445
Scoot Enthusiast
Posts: 199
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Post by dr1445 on Mar 4, 2011 21:52:15 GMT -5
things to look at, auto choke, needle position [lower is leaner], carb float/needle and seat. given the epa likes lean tuned engines, i would suspect a defective choke or float, of course the wrong jets or needle position could have been installed.
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Post by 90GTVert on Mar 4, 2011 21:57:37 GMT -5
Yeah, I had forgot that Bill had a cracked enricher and swapped in the one from his old carb. Definitely make sure that's installed properly and working. If it's working properly, you should be able to remove it from the carb and see that the barrel and needle with slide out over time when it's powered.
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Post by billw129 on Mar 4, 2011 22:07:53 GMT -5
ok I think that the problem is with what you call the enricher. LOL I just took it out and I believe that when I put it in it was just a little bit cocked sideways so it was not seated right. I am going to put the old carb on just to be safe with the new jet. Main only it is a 78
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Post by billw129 on Mar 4, 2011 22:29:28 GMT -5
Ok so put the old carb on with new jets. Start it up and it idles better turn the screw all the way in and it runs good when you grab the throttle and then after hitting rpm it bogs down and almost shuts off. if you turn the screw out at all it just bogs when grabbing the throttle.
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Post by 90GTVert on Mar 4, 2011 22:34:13 GMT -5
I have a feeling a 78 is gonna be a bit small for the main. Have you got the air filter back on? If not, put it back on and then readjust the idle and retry the throttle. You can use the airbox to get an idea of rich and lean. If it improves with the airbox off, that's rich. If you can cover the snorkel or opening in the airbox and it improves, that's lean.
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Post by billw129 on Mar 4, 2011 22:50:31 GMT -5
Ok so i had kind of a compound problem. One of them being a big boo boo. I didnt put the little wire hose clamp on the oil pump pickup and it came off. So I think that was making things a little bit lean. Then the air box that came with the motor was smashed on the back. Impossible to see but it was causing a low vacuum problem and it was running out of gas. Now i have to wait for the pipe to cool down so I can put the oil line back on with the clamp this time. I guess those little things really do something. I put the old air box on and that cleared up the WOT shut down. Now I have to get the carb tunned. What is a good starting point for the screw? Again 90GTVert thank you so much for the help as well as everyone else. I would be lost without 49ccscoot.
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Post by shakerdriver on Mar 4, 2011 23:00:18 GMT -5
I'd start with the screw about 3/4 to 1 turn out and go from there Bill.
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Post by 90GTVert on Mar 4, 2011 23:00:29 GMT -5
It definitely pays to take care of all the details before tuning. Look everything over well while you wait to try and avoid more of this and speed up the process.
Glad we can help. ;D
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