Problem with almost new Trailmaster MID XRX
 

I have a Trailmaster MID XRX with a 200cc engine that I bought right around Thanksgiving. Almost immediately, I started having issues with it bogging down and dying when it is being rode hard for awhile. The kart will refuse to start again until it is given several minutes to sit, then fires right up. Over time of letting it rest and restarting it, the issue will get worse and worse until I can barely limp it back to the house and let it rest for a good long while. The issue happens on both bumpy and smooth driving (happened once out on the road). Talking to some friends, we think that it may be heat or carburetor flooding related since it needs several minutes to be ready to restart.

It's never been left unused for more than a week since I got it and I've been putting Seafoam in the gas tank the whole time, so I'd be shocked if it was a gummed up carburetor already.

Any suggestions on what to try or where to start?

Check your fuel flow. It may be a clogged vent cap or restriction in the petcock or fuel filter.

:evil:
if your tank has a vent line coming out of the top of it that routes down to the airbox, it is a new setup. i have had customers w/ similar problems. speaking w/ the guys at trailmaster we suspect this new system has a problem. they just sent me 2 gas caps from their 150 models, which are the same as the old mid caps. i just got them in so the customers should be picking them up this week to try out. as soon as i get some feedback i will let you know. vent system on the new models seems to be the suspicion. hopefully the cap change is the solution,

Thank you both for your input on this. JERSEYDEVIL, I would definitely like to hear feedback on what you found, it is the newer style with the vent cap on the gas tank. At one point, while the kart was "resting" until I could restart it, I cracked the fuel cap and tried to restart to see if I had pulled a vacuum on the tank. It did not help, which makes me a little pessimistic about the fuel cap being the solution.

GX150, I will check out the fuel flow all the way through to the carburetor. Since you mentioned it though, one time shortly after I got it, I had closed the petcock and allowed the engine to burn off with the intention of not riding it for a few weeks and not wanting gas in the carburetor. When I went to start it up the next time, I found that I was not getting fuel flow all the way to the carburetor. After working my way down the line, I found that the fuel filter was what was not allowing flow through. I resolved this by "milking" the fuel line upstream of the fuel filter which eventually pushed fuel through the filter and started peeing out right at the carburetor connection. Picturing the internals of a fuel filter, I couldn't understand why one would vapor lock or something like that and talking to some smarter guys at work, none of them said it made any sense. I'm going to go to Lowes this weekend and pick up a little higher quality fuel filter to see if this helps any.

FYI, I drained the tank this weekend and inspected the petcock valve and strainer. It had more crud on it than I expected but was far from plugged and I drained a full fuel tank through it very quickly. I installed a new fuel filter that is large and transparent so I can see exactly what's going on in there.

After cleaning everything up and putting it back together, I ran it really hard and after awhile, began having the same problem. I jumped off and looked around back and found the fuel filter to be completely empty. After a few minutes to "rest", the filter finally got enough fuel in it to allow me to start back up and go but without allowing it to fully refill the filter, it stalled out more and more often.

So the short story is that it is clearly a fuel supply issue that is upstream of the filter. I'm going to reach out to the company that sold it to me and see if they are familiar with the fix that JERSEYDEVIL suggested.

Does anyone know the general theory of operation of the vent line from the top of the fuel tank?

sounds like a fuel line size/petcock issue and or insufficient venting allowing a vacuum condition to occur above the fuel in the tank and slow the flow rate down

From messing with and researching the LTZ engine i have in mine, i found when modding and upgrading to the bigger flat slide fcr carbs, people were running into a similar issue with the petcock passages and feed lines not adequate for the fuel demand. in that instance, a petcock from a raptor solved the problem, just as long as it wasn't a chinese knock off.

i'd chase thru that vent system and find a way to safely open it up, or find a bigger petcock and line set from the tank to the filter