2018 Yamaha Gas Acceleration Problem
 

Has anyone had a similar issue that might be able to suggest what is wrong? Spark arrestor was removed a year ago. Engine will start but not accelerate. After running for a minute+ at idle it will eventually pickup rpm and recover. But does this slowly. After running wide open for a few miles and then stopping strong smell of gas. Suspect engine is flooding as the smell of gas is strong. Cart is 2018 but has only 250 hours on it. Air cleaner element looks new. Has been used very little until recently.

This sounds like a problem with the EFI system. I would suggest a search on youtube or the web in general to see if others have reported the problem and possible solutions. I would also talk to the vendor you bought the cart from, some have a 5 year warranty.

After letting the cart sit overnight, it works fine to play a round of golf. When I park it for approx. 3 hours after golf then try to use it the problem will surface. I suspect one of the EFI sensors is producing an incorrect reading which is causing the ECU to do a cold startup and dump too much gas into the intake for a warm engine. I have the service manual for a 2013 but not the 2018. On the 2013 I see four sensors -- intake pressure sensor, engine temperature sensor, air temperature sensor, crankshaft position sensor. I suspect one of the two temperature sensors maybe at fault. Problem is I can’t find any reference to engine temperature sensor on the Yamaha parts page for 2018. I’m hoping someone that may have specific knowledge of this problem might be able to help.

I am not a mechanic and even golf cart engines are getting to a point where in an expert/mechanic is needed. Have a 2021 Yamaha and this does occur to me occasionally.

Sounds like this could be a safety issue too. Imagine needing to quickly accelerate and cart does not respond properly.

When you have the problem did you notice the RED engine light flashing? If so this is giving you an error code for a detected problem. Try this, the next time you have the problem, turn off the cart, then turn on the key but do NOT start, look and see if the light flashes. It flashes a series of long and short pulses, the long for the first(?) digit, and the shoert for the second (?) digit. I have the code chart for the 2017 model.

Have it looked at by a professional and save the time and hassle of random suggestions.

First thing I would do remove spark plug and using multimeter see if resistance good.

https://www.youtube.com/watch?v=N6Ng-yhCeNs

One of many utube video’s how to do it

Why not just change it.

Intake pressure sensor.