Yamaha Gauges and fuel senders
If you own a mid 90’s manufactured Quintrex with Yahama gauges and your fuel gauge is stuck on full, then don’t think for one moment that last load of fuel you purchased is giving you exceptional value for money because you’ve got a problem a big problem, or so I was lead to believe if I trusted one of the blokes I spoke with on the phone!
The problem is Quintrex utilised a tube type variable resistance fuel sender with an inbuilt float that moves insides a tube which is unlike the common arm and float system normally used in conventional tanks and applications. The reason being is that with the arm and float unit every movement especially a rocking motion of the boat would send the fuel needle boucing from full to empty, empty to full to empty again and it would be near impossible to read the guage unless you were in a dead calm situation, bbbzzz, impossible its a boat in the water and its gunna rock n roll all over the shop.
The only draw back with the tube unit is over time the float works it way loose and all of a sudden it would appear your motor if by magic is only sipping the new shell VTech fuel like its a fine drop of port. Howevr inside the tube is a washer or a plug that is mounted on the end of the stem of the fuel sender that holds the float on the stem. Over time being in the fuel it deteriates, then disloges and the float falls in the tank.
I was told by 3 differn’t marine machanics if you can get the float out of the tank you just need to drill a hole in the end of the stem of the fuel sender and put the float back on the stem and place a split pin so the float does not come off and it will work. I tried this but, bbzzzz, it didn’t work. It was worth giving it a go any way to save around $120 but no such fortune my unit had, had it’s day and needed to be replaced.
Then the problems started
Like the old castrol add on TV went, senders aint senders so I needed the exact replacement unit but where did I start? Firstly I needed to measure the stem, mine was 200 mm easy I thought. I then rang Johnsie with the good news who then informed me I needed to know what ohms (measure of electrical resistance) the fuel sender was so i could source a replacement as all systems work on a slightly different measurement of resistance.
Thirdly the flange on top of the unit that screws sender into the fuel tank is a specific size with 5 screws not 6 otherwise they will not line up. So off in search of the net I went and frustratingly after phoning multible boat shops no one could give me clear direction in the ohms resistance of the fuel sender nor a match to my yamaha fuel gauge.
I own Quintrex 475 coast runner and the ohms resistance is 30/240, I ordered the fuel sender through a boat shop and asked all the questions, would the flange holes line up made sure that it was the correct size stem and would the ohms resistance match the Yamaha gauges to make the fuel gauges read right. Easy I thought when they told me if the ohms is the same as the old fuel sender there would not be a problem, (BULLSHIT) connect the new feul sender up it read when the float was at the bottom it read full and the float at the top it was empty ok time to rethink this over.
I will leave this short and sweet
you need to remove gauge from dash, look under the dash you will see ther plate in photo with 2 bolts, remove the bolt and plate and pull out the gauge through the front of the dash leave wires connected
Remove the plug that has no wire to it and it will expose 4 switches the fist 2 switches are for the speedo and calibrate between knots, miles and kms the 3rd switch needs to be in the down position. After adjusting the switches, turn the ignition off and on to reset the gauge problem solved then reassemble.
Its amazing trying to get info out of some people, really, “sure mate I can fix that all up for ya, only $300″,” it’ll take a coupla days tho” and “you’ll have to leave the boat”.