(Need Advice) Crossfire 150R not running right

[Lumberjack]

Hi Guys,

Hoping someone out there can give me some advice on where to troubleshoot next. I bought this buggy new about 4 years ago and it is the kids favorite summer toy.

Buggy: Crossfire 150R

Engine: GY6

Problem: Hard to start...need to give it a little throttle. Once you do get it started it will idle and run at lows speeds OK but not great. When you hold it wide open it acts like the engine is skipping on top end...it will hesitate...buck a littlle, sometimes backfire and just doesn't seem to be as crisp on top end as it always has been. This is going to sound weird but the only thing that seems to help it when it is doing this is to turn the key. It seems to snap it out of its fit for a few seconds.

Troubleshooting done so far:

Compression and Fire: Compression is 150 pounds and I have installed a brand new spark plug that seems to be firing fine when I check it. I have also installed a brand new NGK spark plug boot wire connector.

Fuel and oil: All old fuel was drained and new fuel added. I have checked the flow by unplugging line from carb and it runs through the filter with no problem. Oil level is normal.

Carb and carb boot: I bought a brand new carb from Motowest and installed. With the buggy idling...I have sprayed starting fluid all around the intake and it does not race up. No effect at all.

Valves: Valves were a little tight. Set them to .03 and .04.

Battery: Left the battery on charge all week and it is fully charged.

Grounds, Fuse, Wiring: The grounds look good (No corrosion) and the main fuse is good. I have checked all the wiring and cannot visually see any types of rubs or breaks. Wiring all appears to be in excellent shape.

I feel like it is possibly a coil breaking down but wanted to get your opinion before I head down that road. Any advice is greatly appreciated.

Thank you!

[bear]

Welcome to the forum! Have you checked the ignition switch to see if it is going bad, causing a connection problem?

[Masteryota]

A coil is possible, and they are pretty cheap, even for a performance one. I agree to check the start switch contacts first, as it won't cost any thing but some time.

[Lumberjack]

Thanks guys. I had not considered the switch but agree it would be a logical next step. If the switch checks good I'll buy a coil and see if that fixes the issue.