2.5 HP engine issues

Support forum for our first kit: the PlyFly go-kart
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Posts: 33
Joined: Mon Aug 24, 2015 1:52 pm
Location: Middletown, RI

2.5 HP engine issues

Post by Dave » Thu Sep 24, 2015 3:39 pm

With all the extra EPA and CARB stuff that is in the 2.5 HP engine (and potentially our CARB certified 4.0HP engines for CA), they can be a bit more finicky and tricky to get running. I wanted to put a quick list of things to check if you are having issues getting yours running. Here are the first things I would check. Some are obvious, but sometimes simple solutions are the most easily overlooked.

First off, disconnect the chain. Sometimes misalignment in the chain can make it difficult for the engine to run. It is also good practice to disconnect the chain while working on the engine, so that if it suddenly starts/revs up, the kart won't run away from you (alternatively, having the drive wheels off the ground would also prevent that). If it runs with no chain, then re-align the sprocket, put the chain back on, and try again. There should also be a little bit of slack in the chain, so the clutch doesn't bind up.

Make sure the kill switch is on.

Check the gas tank for fuel.

Check the oil. The oil level switch has given us issues, but it typically works when the kart is sitting still. Make sure there is enough oil in the engine. If the oil is full, you can disconnect the low oil switch (yellow wire near the kill switch) if you'd like. If you do, take extra care to regularly check the oil level.

Next is to make sure the spark plug wire is securely on the spark plug. Sometimes this can loosen up in shipping or could get pulled when handling the engine, and that would cause a no start condition.

I have found with the 2.5HP engines that it won't always start on full choke. Adjust the choke to 3/4 of the way closed and give it a shot. Then open it up slowly as the engine warms up. These engines can be a bit finicky before they are broken in. Try different amounts of choke rather than fully open or closed.

ONLY WITH THE CHAIN DISCONNECTED, try holding the throttle lever wide open while trying to start it.

If it is starting, but not staying running, try turning the idle up a bit. There is an adjustment screw on the carburetor, near the choke lever. It may have a plastic cap on it, with a phillips head screw inside. Turn it up a few turns and see if it stays running. If it does, back the screw off until the engine sounds like it is going to shut off, then turn it back up a half turn.

If anyone else has any tips or tricks they found to help the 2.5 HP engine run better, feel free to post them up here!
Flatworks Engineer

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