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Post by gabriel on Oct 24, 2013 19:57:51 GMT -5
Howdy folks,
I have a Kaitong 150cc Chinese scooter that I picked up a year and a half ago. Very recently it began to suddenly lose power while accelerating. It began happening about a quarter of the way into a new tank of fuel. Here's the background:
• Kaitong 150cc
• GY6 engine
• Replaced the carburetor 6 months ago
• Replaced the factory spark with a fancy iridium spark plug 6 months ago
• Replaced the spark plug wire 2 months ago (old one was cracked and it was wiggling itself loose)
It starts beautifully and idles just fine at 1500rpm.
If I twist the throttle suddenly it will stall and die.
If I slowly twist the throttle it will rev up to about 3800 - 4200 and then drop back to 1500.
After this happened:
• I replaced all the fuel lines, because some of the rubber was old and cracking.
• I drained and cleaned the carb.
• I checked my spark gap (it's just a little past .6 mm, manual says to have it between .6 and .7)
-- The spark is a bit dark and sooty, which I think means I've been running a bit rich.
• I re-adjusted my air-fuel mix to lean it out a little bit.
That concludes all the maintenance I've figured out how to do since I got the thing, but it hasn't resolved the sudden loss of power issue, and I need help! Any ideas or suggestions will be greatly appreciated.
Thanks in advance!
Gabriel
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Post by JerryScript on Oct 24, 2013 20:13:08 GMT -5
Check your valves. They should be .003-.004" but often get out of adjustment.
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Post by skuttadawg on Oct 25, 2013 0:05:41 GMT -5
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Post by rockynv on Oct 25, 2013 1:34:43 GMT -5
Yep check the valve adjustment and consider some fuel treatment in case you got into some bad gas. With the cooler weather here it is possible you filled up at a station with a low tank and got some condensation or crud.
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Post by larry001964 on Oct 25, 2013 11:26:08 GMT -5
Hi Gabriel
Just a thought, other than valves, have you checked your air filter ? is it clean ? have you checked your fuel filter ? is it in good shape ?
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Post by gabriel on Oct 26, 2013 14:59:48 GMT -5
Howdy Folks,
Okay, I just got done adjusting the valves. I started by making my intake .003 and my exhaust .004. Same as before, starts fine, idles fine, hits ~4000rpm and drops back to ~1500. The manual for the bike says to make the in .0019 and the ex .0024. My valve tool only has .002 and .0025, so I used those as the closest. Unfortunately, the issue remains.
I checked my air filter, it's been on the bike since I bought it and looks disturbingly clean, like, nearly new kind of clean. I checked the tubing between the air filter and the carb for holes and patched one tiny crack.
I forgot to mention that when I replaced the carb I also replaced the fuel filter with one of those fancy clear glass filters. It LOOKS clean.
I'm in the process of draining my tank to replace it in case it was bad gas. I'll report back once I'm done, but while I'm at it, do you have recommendations for a fuel system cleaner?
Thanks again for your help!
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Post by gabriel on Oct 26, 2013 15:32:25 GMT -5
Well, I've adjusted the valves and replaced the fuel. Still drops power as soon as I get it up to 4000 rpms.
Any other ideas?
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Post by JerryScript on Oct 26, 2013 15:46:25 GMT -5
Sounds like your fuel petcock may be bad. At high RPM, the vaccum pressure drops, and if the fuel petcock is going bad, there may not be enough vaccum to open it up. You can bypass the fuel petcock temporarily to test.
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Post by gabriel on Oct 26, 2013 18:08:49 GMT -5
My fuel tank is a good 12 inches higher than the carb, so I took the petcock & shutoff valve out altogether, kinked the vacuum line and ran fuel straight from tank -> filter -> carb. Sadly, it's acting exactly the same as before.
I'm ordering a new petcock anyway, since it's only $10 online.
Any other ideas?
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Post by alleyoop on Oct 26, 2013 18:20:27 GMT -5
Yes, check the diaphgram it may have a leak and will act like that, it will raise your needle out of the main jet then loose pressure and it will drop back down. Make sure the Rubber Diapghram is in the grove around the top of the carb and the cover is on there good and sealing.
Alleyoop
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Post by gabriel on Oct 26, 2013 21:26:13 GMT -5
Alleyoop got it. When I previously cleaned the carb I did NOT disassemble the diaphragm. I pulled it out and the pin stayed in the carb. There is a little figure-eight clip intended to hold the pin in the diaphragm and that clip was broken.
The clip to hold the pin looked difficult to replace, so I just ordered a new carburetor altogether. It should be here Wednesday or Thursday, at which point I'll be back to update this thread again.
Thank you all so much for your help! I've learned a lot from this experience.
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Post by alleyoop on Oct 26, 2013 21:36:54 GMT -5
Gabriel,
FANTASTIC!! Most ACE hardware stores have those clips they are called "E" clips and they have all sizes, you can take the needle with you and see if they have a small enough one that will work.
Alleyoop
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Post by gabriel on Nov 5, 2013 21:03:58 GMT -5
THANK YOU ALL SO MUCH FOR HELPING ME WITH THIS! You guys are amazing.
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Post by ltdhpp on Nov 6, 2013 11:01:52 GMT -5
I never had any luck finding a replacement 'E' clip that fit well for mine, I wound up using a tiny hairpin style clip and it worked great.
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..BAD TO THE BONE..
