Coleman CT200U dies past 50% throttle

[Zheking]

Short time reader, first time poster. I'm pretty mechanically inclined, but this is my first toy with a carb ever.
Backstory,

Bought a coleman CT200U used (great price!). would start, and idle, but over 50% throttle would die. Figured ok, just a dirty carb, and since the OEM carb jet has that "anti-tamper" junk, I just went ahead and ordered the stage 2 kit from OMB warehouse that had a new carb / jet.

Put the stage 2 kit on, set the valve backlash for the new springs (Forgot to set it to TDC and the exhaust valve fell down in the cylinder, oops. 4 bolts to pull the head and get it out, took 10 minutes, wasn't that bad), put the new carb w/ new jet on. Exact same problem. I pulled the fuel line off the carb, it's free flowing, and the gas is fresh and tank looks clean. I pulled the bowl, and it didn't seem to have as much fuel as I'd like coming into the bowl, but it reading the reviews / Q&A on OMB's website, no one else has reported a lack of fuel issue with the carb / jet it comes with. To me, it seems like it's getting lean, but since no one else reported the problem and it did the exact same thing prior to putting the stage 2 kit on, I have a hard time believing that is the issue. I did try taping off a lot of the filter to reduce air intake, didn't seem to help. (if the air filter was on the other side I'd drive down the road spraying starting fluid in to try and test the leanness, but it's hard to do with it being on the same side as the throttle). Running with the choke on / off made no difference. Have not checked compression (as my compression gauge has come up missing) and I can't find a factory service manual for this thing to tell me what compression should be anyway. Did put a new plug in it when I put the stage 2 kit on (the racing plug on OMB's website frequently bought with the stage 2 kit)

I've exhausted everything I know to check, and it's hard for me to justify taking it some where when I can get a new motor at harbour freight for $200 (minus 10% coupon they always seem to have), figured I'd check here if anyone had any thoughts on what to check before I just say screw it and get a new motor (or maybe even a little 200CC diesel motor if I can find one!). Thanks.

 

[Bansil]

Since fuel flows good out of tank, have you removed the needle and "back flushed carb" (with fuel line/filter off?) Maybe something is clogging the needle/seat from getting fuel into bowl...or even pull out new main jet and clean out passage way.

And welcome! Good luck

 

[Denny]

Is the little black plastic spacer between the carb and head installed correctly? Not upside down or backwards. Little hole lines up with the one on the carb? Check float level. How does the plug look?

 

[Zheking]

Since fuel flows good out of tank, have you removed the needle and "back flushed carb" (with fuel line/filter off?) Maybe something is clogging the needle/seat from getting fuel into bowl...or even pull out new main jet and clean out passage way.

And welcome! Good luck

I've had the carb apart a couple times trying to diagnose. It's brand new carb and jet and based on the fact that it will start and idle and I can get it down around the neighborhood as long as I keep it under 50% throttle I don't believe anything is buggering up the carb.

Is the little black plastic spacer between the carb and head installed correctly? Not upside down or backwards. Little hole lines up with the one on the carb? Check float level. How does the plug look?

Plug is brand new. Spacer is installed correctly with the little hole. Float moves freely. unsure how to check the level with the bowl off? (like I said, I'm new to carbs)

 

[Denny]

Remove carb. Remove float bowl. Turn carb upside down. Float should be level with bowl gasket area or slightly higher (1/32”) opposite hinge area. Do not push on float to lower or raise it. Bend tab at needle.

 

[madprofessor]

$200 for Harbor Freight? Must include some shipping. Predator 212's on website list for $140 everyday.
How much can you sell the used motor for? Only have to prove it cranks up to sell it.

 

[Zheking]

Remove carb. Remove float bowl. Turn carb upside down. Float should be level with bowl gasket area or slightly higher (1/32”) opposite hinge area. Do not push on float to lower or raise it. Bend tab at needle.

Float bowl was fine.

$200 for Harbor Freight? Must include some shipping. Predator 212's on website list for $140 everyday.
How much can you sell the used motor for? Only have to prove it cranks up to sell it.

Yes I was just noticing that when I was searching. I was just saying $200 off the cuff because you have to order a clutch and stuff for it too. I think the 212 predator is the route I'm going to go as I'm tired of fooling with this thing and need it running for summer / fall camping / Nascar trips. (no more walking a mile to the dumper at Talladega. Calling this mini bike "The Dega Dumper Runner"). If I get $50 for the old motor I'll be happy.

The research I've done is the motor should bolt right in, need a clutch and to make a spacer for the clutch.

Would this be the right clutch? 12 tooth for a #35 chain? I don't know the chain # / rear gear tooth count on the c200u / gear ratio. Thanks in advance.

Max Torque SS Clutch 3/4" Bore 35 Chain - 12 Tooth

OMB Warehouse - Go Kart Parts and Mini Bike Parts. OEM and Aftermarket supplier of Outdoor Power Equipment Parts, Arborist and Landscape Supplies.

www.ombwarehouse.com

 

[madprofessor]

Clutch sprocket# must match axle sprocket#. Everything I see on the Coleman 200 calls for a #420 chain, so #420 sprockets. The #35 chain above only works with #35 sprockets.
#420 is a stronger 1/2" chain, #35 is 3/8" chain. Others here can tell you if #40, #41, #420 are all compatible or not. You just need to know for certain what # that axle sprocket and the chain is, get clutch to match. Call OMB or others with questions.

 

[Zheking]

Got extremely tired of messing around with the old motor and ended up just getting the harbor freight 212 predator. The only thing I've put on from the stage 2 kit is the exhaust and this thing is a beast. It will rip and ride wheelies. It's at a point where I'm like "Do I need the rest of the stage 2 kit even?" But also, "Well, I bought it, might as well use it." Did disconnect the low oil pressure sensor unit and wired in the stock kill switch in place of it. I couldn't find the right clutch spacer anywhere in town, didn't wanna wait 2 weeks for something from the internet, and I saw where others have used a piece of pipe they cut. I ended up using an old titanium wedding band that's been sitting in my desk drawer 10 years. Sometimes divorce pays off.

 

[Hellion]

I just hate it when folks "throw in the towel" and fix things by buying new things. That ain't fixing or repair, sir.

Now when you say the original engine dies at 50% throttle, do you mean it shuts off completely and ceases to run or did it just "hiccup" or bog down or "fall flat on its face"?

 

[Zheking]

I just hate it when folks "throw in the towel" and fix things by buying new things. That ain't fixing or repair, sir.

Now when you say the original engine dies at 50% throttle, do you mean it shuts off completely and ceases to run or did it just "hiccup" or bog down or "fall flat on its face"?

cease to run. dies. completely turned off.

typically I don't just throw parts at something, but this was a time value money thing. spend 30 minutes changing to a better / bigger / stronger motor and work 2 hours at work to pay for it. Or spend who knows how many hours on a smaller / older / who knows what the old owner did to it motor trying to figure it out.

needed it ready for camping and such anyway.

 

[madprofessor]

Congratulations on the payoff. 4 times for me and never saw any payoff from any of them besides getting away from them.

 

[Zheking]

Congratulations on the payoff. 4 times for me and never saw any payoff from any of them besides getting away from them.

You mean you never had any luck / success with the predator motors?

 

[madprofessor]

Sometimes divorce pays off.

No luck / success on my 4 divorces. On the opposite hand, the Predators have always taken to adaptations and improvements under my care and efforts very successfully.

 

[Mr Mike]

I realize I’m joining in on an old post but I have had the same problem with the BT 200 X with only eight hours of runtime. I bought this new in the box put it together myself and I should’ve realized when the front forks were assembled wrong the throttle was upside down there was no chain guard and the bolts in the headlamp were falling out because they were loose that I would probably run into problems down the road. AnyWho in my case it started with a little runaway at idle and ended up into the bike bogging and then not throttling up correctly. So I lifted the bike off the ground while idling and the rear wheel accelerated quickly with no load so I put on a new clutch. The problem went away about 50% but the bogging kept coming back when the engine got hot. For some reason I decided to check the pressure on the cylinder cold and as I was installing the gauge I noticed it was very easy to unscrew the spark plug. Wouldn’t you know that when I put the spark plug back in after it passed the pressure test holding at 55 psi for 15 minutes that all my problems one away. Looking at the manufacturing date from the vin number I have concluded that the Covid factory was busy producing other things that day