Yamaha Golf Cart Fuel Pump Problems And Solutions

The fuel pump is a very important and integral part of the Yamaha golf cart. The Yamaha golf cart uses a 4-stroke, gasoline OHV single cylinder engine and integral to the operation of the engine is the fuel delivery system which includes the fuel pump that draws fuel from the 6.6gallon (25 liter) gas tank to the engine. The fuel pump enables the engine to receive the required amounts of fuel it needs to run.

Table of Contents

Yamaha Golf Cart Fuel Pump Operation

The Yamaha golf cart uses a vacuum pump that has 3 openings, the inlet pot, outlet pot and vacuum pot. The Yamaha golf cart pump has two diaphragms for separating the inlet, outlet pots and pulse from one another. When the diaphragms start pulsing, fuel is drawn from the gasoline fuel tank to the inlet chamber, then to the outlet chamber. From the outlet chamber fuel is passed to the engine. The pump uses pressure from the crankcase. This pressure is called pulse since it is generated at the bottom of the piston in the golf cart engine block when the crankcase turns. The fuel pump of a Yamaha G14 golf cart has a standard pressure of 178PSI. The minimum pressure must always be 142PSI. An electric fuel pump in a Yamaha G2 cart often has a low pressure of 3 to 5PSI with ¼-inch lines. In some cases, the fuel pump gets activated when the fuel pressure is lower than 2PSI. It gets turned off when the pressure reaches 4.5PSI. In normal operation the Yamaha golf cart fuel pump works perfectly well to pump fuel from the fuel tank to the engine but it can however develop some problems that will be discussed below.

1. Deterioration Of Rubber Fuel And Vacuum Lines

Damage can occur to the fuel and vacuum pipe lines of the Yamaha golf cart resulting in holes and cuts. Often these holes and cuts that develop on the rubber lines are very small and hard to see however they can cause significant problems to the operation of the Yamaha golf cart fuel pump. These holes in the rubber pipes may allow air pockets and dirt to enter and contaminate the fuel mixture. Gasoline can also easily vaporize and escape through these holes and create potential fire hazards. To solve this problem with the Yamaha golf cart fuel pipe lines regularly inspect the lines for any visible cuts. It is also advisable to try and smell the fuel vapor that may emanate from the lines. Replace the lines if fuel smell emanates from the pump lines since this usually indicates problems with the lines.

2. Debris Buildup

Dirt can build up in the Yamaha golf cart fuel pump and clog it despite the use of the inline fuel filter. This can cause problems in how the pump functions hence affecting the overall performance of the golf cart engine. To solve this problem the golf cart fuel pump may need to be cleaned or replaced if no longer operational. The Yamaha golf cart fuel pump if fitted below the golf cart seats, hence to gain access to it, remove the seats and air filter module to reach the fuel pump. Remove the fuel pump from the golf cart by removing its bolts and taking out the fuel pump lines along with the vacuum line. Clean each component using a cleaner or gas specifically intended for this purpose. Also clean the tank and cap vents. Once the cleaning operation is done assemble the fuel pump once again and fix it back to its original position. This should address the debris problem.

3. Diaphragm Damage

Damage to the diaphragms in the Yamaha golf cart fuel pump usually due to lack of maintenance and extensive use can cause problems with the pump performance, as such replace the broken or torn diaphragms and reassemble the pump and put it back into position once done to solve the problem.

4. Fuel Breakdown Due To Long-Term Storage

If the Yamaha golf cart stays for a long time without being used the fuel inside the fuel tank can breakdown. This often changes its quality and consistency and hence affecting the performance of the fuel pump. If this problem arises unhook the gas lines from the pump and drain all the fuel inside the fuel pump into an approved gasoline storage container. Also empty the contents of the carburetor during this time and clean the pump. After cleaning the pump, it can be reconnected and new fuel pumped from the Yamaha golf cart fuel tank. This should address the problem and restore normal operation of the Yamaha golf cart fuel pump.

5. Engine Problems

Since the Yamaha gold cart fuel pump works on the vacuum pressure from the engine crankcase, to ensure no problems develop with the fuel pump, check for any damages in the engine or leaks in the crankcase as this can affect the vacuum pressure and limit the functionality of the pump. Also look out for problems with the case gasket, faulty crankshaft seal or any oil leaks. These usually give good indication as to whether there may be problems developing with the fuel pump which will limit the power production of the engine. Replace worn-out parts and take the Yamaha golf cart for service if any problems like oil leak develop.

6. Ethanol Mix

Fuel with ethanol can cause problems with the Yamaha golf cart engine components and affect the performance of the Yamaha golf cart fuel pump. This ethanol mixture usually causes problems of rust deposits in the fuel supply system. To solve this problem, it advisable to rather use 87 octane fuel as the alternative for the Yamaha golf cart engine since it has 10% or less ethanol content. Also use a fuel stabilizer for smoother running of the golf cart engine and ensure the engine is completely dry before long term storage.

7. Vapor Lock

Vapor lock can prevent the engine from smoothly running without the need for additional priming action to increase the amount of fuel the carburetor receives. To test whether there is vapor lock connect a marine primer bulb in between the fuel pump and the fuel tank. Pump with primer bulb for a while till the carburetor is loaded fully with fuel. After this start the engine and check if it continues running without the priming action. If it does, there is a vapor lock. In this case replace the existing hose pipe from the fuel tank to the filter with a slightly larger hose. This will serve to ensure that the filter is never dry and has some fuel always, which in turn will prevent vapor lock. This should address the vapor lock problem and allow the Yamaha golf cart to run properly.