Changing The Fuel Filter On A Yamaha 200 Hpdi

Changing the fuel filter on a Yamaha 200 HPDI can be a challenging task, but with the right tools and knowledge, it can be accomplished successfully. The process involves dealing with various components, such as the clear plastic bowls, the fuel lines, and the filter itself, which is located under the cowling. It is important to relieve the VST fuel pressure before attempting to change the filter, as this can impact engine performance. There are also multiple filters that need to be changed, including the low, medium, and high-pressure filters, each with their own unique process for removal and replacement.

Relieve the VST fuel pressure

To relieve the VST fuel pressure on a Yamaha 200 HPDI, follow these steps:

Firstly, locate the VST filter. This is usually found near the top of the engine, often described as the "metal-cased filter near the top". It is one of three fuel filters, the others being the low-pressure filter (with a plastic housing) and the high-pressure filter (in an aluminium housing).

Next, before you begin any work on the VST filter, it is important to relieve the fuel pressure. This is a crucial step, as mentioned by a Yamaha technician. Failure to do so could result in injury or damage to the engine.

Now, to relieve the pressure, you will need to access the fuel lines and the fuel pump. Cut the zip ties that hold the fuel lines in place and gently pull them off. There should be two fuel lines, one for the inlet and one for the outlet. Once these are removed, you can then relieve the pressure in the fuel system by opening the fuel pump and allowing the pressure to escape. It is important to place a rag underneath to catch any spilled fuel.

After completing these steps, you have successfully relieved the VST fuel pressure and can proceed with changing the fuel filter. Remember to exercise caution when working with fuel and always refer to official Yamaha guidelines and safety procedures.

Remove the HPDI slip joint connector

To remove the HPDI slip joint connector from a Yamaha 200, you'll need to first relieve the VST fuel pressure. This is important! Next, follow these steps:

• Disconnect the wire from the blue connector. Use a screwdriver to gently pop it free, or pull it free from the bowl bottom.
• Try to remove the clear bowl with channel locks. It may come off, but if it's tight, that's okay—just be prepared for some fuel to leak out.
• Take note of the flow arrows on the top of the housing. You'll need to remove the fuel lines by carefully cutting the zip ties and gently pulling the hoses off.
• There are two bolts that hold the filter to the motor. Remove these and pull the filter free. Put the bolts back into the bracket.
• Drain the fuel out of the filter.
• Place the bracket in a vice, cushioned with scrap wood, and tighten it carefully to secure the bolt heads.
• Now, apply very firm but slow and steady pressure to the clear bowl. It may feel like it's almost ready to break, but this is normal. Keep applying pressure until the bowl comes loose.
• Once the bowl is loose, spin it off and remove the old filter.

Some additional tips for this process include:

• Leaving the clear bowl to sit for 24 hours after removal, allowing it to shrink back to its regular size.
• Placing a bag of ice on the bowl to help it shrink.
• Using the freezer trick for rubber o-ring gaskets on the aluminum pump housing, as freezing them will make them shrink and grip the mounting flange edges.

Remove the wire from the blue connector

To remove the wire from the blue connector, you will need a screwdriver. This is a delicate process, so be sure to use the screwdriver tip to gently pop the wire free from the connector. You can also try pulling the wire free from the bowl bottom, but be careful not to use too much force as you don't want to damage the connector or the wire.

Once the wire is disconnected, place a rag under the bowl as some fuel will leak out. You will then need to remove the fuel lines from the bowl. These are held on with zip ties, so carefully cut these and gently pull the hoses off. There are two bolts that hold the filter to the motor. Remove these and pull the filter free. Put the bolts back into the bracket and take the assembly to a vice to drain the remaining fuel.

Now, carefully tighten the vice so the bolt heads are secured. Remember that the housing is made of aluminum, so be gentle. You can cushion the vice jaws with scrap wood to avoid damaging the assembly.

At this point, you can proceed to remove the clear bowl. This may require some force, but be careful not to crack the plastic. Firm and slow pressure should be enough to get the bowl loose. Once it's loose, spin it off and remove the old filter. Remember to check the O-ring for any cracks and replace it if necessary.

It's a good idea to let the clear bowl sit for 24 hours after removal to allow it to shrink back to its regular size. You can also place a bag of ice on the bowl to help it shrink. This will make it easier to install the new filter and bowl.

Clean the O2 sensor

To clean the O2 sensor of a Yamaha 200 HPDI, you will need:

• A new gasket set (two gaskets per sensor)
• A can of Yamaha Combustion Chamber Cleaner (or Ringfree or carb cleaner)
• An oxygen sensor socket 22mm or 7/8" (a special socket with a groove cut in the side to allow the wires to exit while removing the sensor)
• A 10mm socket and socket wrench
• A torque wrench
• Wire ties
• A stiff toothbrush

First, cut the wire ties off the bundled wires that are holding the four wires from the oxygen sensor. Cut the wire tie holding the rubber boot and wires on top of the oxygen sensor housing. Slide the rubber boot up and off the oxygen sensor housing. Unclip the two wire connectors attached to the four wires on the oxygen sensor leads.

Remove the two 10mm bolts that hold the oxygen sensor cover in place. Carefully lift and remove the cover. Place the oxygen sensor socket on the nut that loosens the sensor, pushing the wire shield down towards the sensor to protect the wires. Loosen the sensor but do not remove it. The sensor is torqued to 35 lbs, so it will be tight.

Now remove the three 10mm bolts from the bronze housing and take out the oxygen sensor. Set them on a clean towel. You will see a small, round tube (the sniffer tube) sticking out of the motor block. Gently but firmly wiggle and pull on the sniffer tube until it comes out. Spray about 1" of the combustion chamber cleaner into a clear glass, then soak the perforated part of the sensor in the liquid. Do not submerge the sensor past the perforated bottom portion—the threads should not be in the cleaner.

Clean the bronze housing and sniffer tube by gently scraping, scrubbing, and soaking them in another glass with cleaner. There will be some hard carbon buildup on these parts. Clean inside the bronze housing using a cloth towel with cleaner wrapped around a Phillips-head screwdriver. Make sure the hole in the sniffer tube is clear of debris.

After cleaning, dry the parts with a clean towel and set them aside. Gently brush the sensor with a toothbrush—there should not be much buildup. Dry the sensor gently with a towel and, if you have one, a little compressed air.

Now remove the old gaskets off the motor and clean the hole where the sniffer tube came out. You can use a single-edge box cutter blade to remove all the gasket material left on the motor block.

To reassemble, place the cleaned sniffer tube back into its cleaned home in the motor block. Screw the cleaned oxygen sensor finger-tight into the clean sensor housing. Place the large gasket for the plastic housing in place, making sure the hole lines up with the bolt hole. Insert the three bolts into the bronze sensor housing and place the small gasket on the bottom two bolts. Line up the sensor bolts with the holes and finger-tighten the bolts.

Tighten the bolts to 3.5 lbs first, then retighten them each a little at a time until the specified 10 lbs of torque is reached. Place the oxygen sensor socket onto the oxygen sensor, being careful not to damage the wires or sensor. Torque the sensor to the specified 35 lbs.

Carefully slide the plastic housing over the wires and back into position over the oxygen sensor and housing. Be careful not to damage the wires or cover gasket. Place the two cover bolts in the holes and tighten them to the specified 6.5 lbs of torque. Slide the rubber boot back over the top of the plastic cover and put a wire tie to hold the wires and rubber cap in place. Reconnect the two wire connectors and re-bundle the wires with wire ties.

Check the O-ring for cracks

To check the O-ring for cracks, you must first remove the clear bowl. Place a rag underneath it to catch any fuel that might leak out. Next, carefully cut the zip ties and gently pull the hoses off. There are two bolts that hold the filter to the motor—remove these and pull the filter free. Put the bolts back into the bracket and take it to a vice. Now, drain the fuel out.

At this point, you can begin to inspect the O-ring for cracks. If you spot any, you will need to replace it. It is recommended to use a new O-ring when reassembling, even if no cracks are found. This is because O-rings can degrade over time, and it is a small price to pay to ensure the fuel system remains sealed and leak-free.

When refitting the clear bowl, be sure to leave it for 24 hours to allow it to shrink back to its regular size. Alternatively, you can place a bag of ice on the bowl to help it shrink. This step is important to avoid forcing or stripping the threads when reassembling. Once it goes on easily by hand, tighten it until it seats fully.

Frequently asked questions