Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 M3W Fuel Pump Replacement

I think Kolvites is on the right track. A seized bearing causing the pump to draw more current. A pump sitting in a liquid so far from a heat source surely must be cool. Unless the bevel box is getting so hot that it is cooking the fuel, and I seriously doubt that.

This does all make me think that my habit of filling up the tank when I know I am down the last 1-2 gallons may not help pump longevity? Perhaps keeping the tank at least 1/3 full would help with heat dissipation for the pump?

The pump collector pot sits on the bottom of the tank and will not allow fuel into it when the level drops below the top, so thats about 3" or 4" of unusable fuel in the bottom of the tank, plenty for cooling. Bunny considered drilling some holes part way down the side of the pot to allow using some more of the fuel in the tank, an idea that has some merit. The only down side of this is that the last few inches of fuel would mean the pump wasn't running fully submerged, this could cause problems maybe?

Most of us don't trust the random fuel contents indications and reset the odometer at every fill up, then do about 200 miles before looking for fuel. I have never had any problem with low fuel using this method. I really don't think any heat build up in the fuel is a problem in the normal installation. I have never found the tank getting hot in use, well not in the UK.

Don't be drilling holes in the bucket.

they already considered handling an empty bucket install.
there is a check valve at the bottom of the tank. Installing the pump assembly with an empty bucket into a fuel tank, the check valve will allow fuel to flow into the bucket.



It's a flapper valve that will let fuel from the tank flow into the bucket, but when the pump is running, while filling the bucket with returned fuel, the valve closes so the fuel in the bucket does not flow back into the tank.

I agree with the common suspicions about the accuracy of the fuel gauge. It's supposed to read 0% when there is 6.6 gallons of fuel left in the tank.
My fuel gauge is reading 32%, but there was only 5 inches of fuel in a tank that's 11 inches deep.

Stay tuned. If it's not raining tomorrow, I will begin my tests of fuel temperature.

The pump is not cooled by the fuel around the outside of the pump, it's cooled by the fuel flowing through the inside of the pump...where the heat is generated.

As long as fuel is flowing through the pump, it's being cooled, and all that takes is a few inches of fuel in the bucket to keep the intake submerged.

What about the quality of the fuel, i.e. the amount of ethanol? Is the problem of the failing pump the use of modern fuel with 10% ethanol? For the moment I don't use this fuel, but buy the more expensiv old fashion fuel, which is sold in Germany (Super Plus instead of Super E10). My Dreirad is from 2013 with 20.000 km, no problems so far with the pump.

Achim

My 2013 3W has been drinking 10% ethanol fuel since birth. With 6,600 miles on it, I see no evidence of a problem with the ethanol laced fuel.
Ethanol in fuel was first introduced in the U.S. in 1978, many cars were still using carburetors. The ethanol was softening and dissolving gaskets. Auto manufacturers quickly came up with answers. By 2011 in the U.S., 90% of fuels contained 10% ethanol.

The only benefit to using ethanol in fuel seems to be the income for corn farmers.

Here's my first report on fuel pump and fuel temp. test:

I installed the original fuel pump. Has 6,000 miles on it.
Aprox. 1/2 tank of fuel.
Outside air temp. 58 degrees F.
fuel temp. in fuel return bucket, 59.5 degrees F. (3W was sitting in garage)

I ran the engine at idle to make the engine overheat by running without any cooling air, creating skip fire from overheating.

After 5 minutes of running... no skip fire yet. The fuel pump outlet temp. was 74 degrees and the fuel in the bucket was 71.5 degrees.

After 20 minutes of running, the engine overheated and went into skip fire. The cylinder heads were aprox. 350 degrees. At this point, the fuel in the bucket was 86 degrees and the fuel pump outlet was 88 degrees.

The machined aluminum blocks that hold down the injectors and also act as the fuel rail/manifold were 99/100 degrees F.

The circulating fuel is COOLING the fuel rail/manifold, its' proximity to the hot engine was not increasing the fuel temp. to any significant degree. Any heating of the fuel appears to be mostly from cooling the pump motor.

When the raining stops, I'll take a hard run and record the results. Over time, and several rides, I'll see how the variables effect the fuel pump temperature.

Good info Kolvites! Keep up the good work👍

Curious, what model fuel pump did you use? At work I cannot access the link at the start of this thread