1997 Club Car DS Engine Running Rough at Higher Speeds

[Skizer]

Hi all, looking for help/ideas with this. I picked up this 1997 Club Car DS from a guy who hasn't used it in a few years. It sat under a tree in NY weather. He said it needed new micro switches and it'll fire right up. Well he was partly right. So this is what I did. Replaced all 4 micro switches (bought off amazon), empty gas tank and wipe out, replace all fuel lines and pump, replaced carb (bought off amazon), replaced plug (can someone verify what type i need), new air filter and new battery. So now what its doing. Turn key, light comes on. Press gas pedal a bit, starter kicks in and starts turning motor. Give it a little bit more gas and usually starts (maybe a 80/20% chance of starting). seems to run and sound good at that low speed. Give it more gas, about half pedal now, motor gets faster. Now, once you exceed that half way mark to full speed, anywhere in that range, she gets boggy, gets to me a soft backfire sound, and just does not sound right. Go back to pedal half way and she smooths out and seems to run ok. It does this all the time, cold, warm or hot engine. We tried adjusting the screw in the carb, took brown wire off ground on rev limiter, checked exhust for blockages, and cleaned off flywheel as there was surface rust on it. Anyone have any ideas? I can try to upload a video clip showing what its doing if needed. Thanks in advance for your thoughts.

[CP241]

I’d start by ditching the Amazon carb and giving the oem keihin carb a good cleaning. Amazon/China carbs are garbage. Don’t overthink it, start with the easy stuff and rule that out first.

[KartMan154]

Originally Posted by CP241

I’d start by ditching the Amazon carb and giving the oem keihin carb a good cleaning. Amazon/China carbs are garbage. Don’t overthink it, start with the easy stuff and rule that out first.

Had the same problem, fixed it by cleaning the original carb.

[Skizer]

Update - clean OEM carb and put back in. Same result. Had some friends over talking about it. They were thinking bad ignition coil. With the backfiring back into carb and smell of fuel when we would hit about half way on pedal, they thought it wasn't getting enough spark to burn the fuel. Thoughts?

[CP241]

Generally these coils either work. Or they don’t. I don’t think I’ve ever seen one that is fine at lower speeds and fails at higher speeds.

Pull the plug and hold it against the valve cover bolt. What color is the spark? Yellow? White? Blue?

It’s possible the rev limiter is failing at higher rpm but when anything goes wrong with the coil, rev limiter, etc. it will generally kill spark completely. Not just make it run a little funny.

I’d also adjust the valves. Generally the first thing I do anytime I buy any type of machine is adjust valve lash. .005 intake and exhaust is what you want.