Racerone,
This plastic washer is located on the bottom of the powerhead? Easy to see or the powerhead needs to come apart too? Thanks for additional info before I attack.
Marty
You just need to pull the powerhead, then the exhaust tuner plate is accessible. The water tube grommet sits in the tuner plate, with the tube in the grommet. The plastic washer is placed on top of the rubber grommet and this keeps the grommet from shifting upwards (and also promotes a good seal). The old-style plastic washers did warp with heat, in extreme cases they would squeeze shut and restrict water flow. The upgraded washer is made of phenolic or other temperature-resistant material and doesn't warp like the old one did.
You'll want to pull the lower unit before you pull the powerhead. If you have an air compressor, you can put a rubber hose on the end of the water tube and blow air up the tube to check for flow. Or, run water up the tube. You'll know right away if the flow is restricted.
Note that if you pull the powerhead and don't find a problem with the water tube/grommet/washer, likely the water passages in the powerhead are silted/corroded. With the powerhead on the bench, pretty easy to work on the water jacket cover (over the spark plugs) and the exhaust manifold. Use extreme caution, if any bolts don't break loose with normal force on the wrench, you'll need to apply heat from a propane or MAPP torch to help free them. Very easy to twist the bolt head right off of the 1/4" bolts.
It's very common to see a lot of silt and corrosion products inside the block, all this silt builds up and restricts water flow.
However, if you pull the powerhead and find a bad washer/grommet, there you go. Pull out the grommet, water tube, scrape the cavity where the grommet goes, and install new parts. A thin coating of Permatex #3 in the cavity, on the grommet, and on the outside of the water tube, will prevent any corrosion products from building up and squeezing-shut the grommet/water tube.
HTH............ed
