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These hydro-engineered test tanks are designed for outboard motors. Internal baffles virtually eliminate cavitation. these tanks are designed to be used with standard propellers, eliminating the need for costly test wheels.
Left the motor into the test tank is made easy by the hydraulic lift arm. the air hydraulic lift arm also doubles as an adjustable work stand. By lifting the motor comfortable work positions, the lift enables the technician to work on both the powerhead and lower unit with no back strain. combined, these features make carburetor, ignition and other fine tuning adjustments efficient and effective, eliminating expensive customer returns.
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A couple of problems that can be caused by a defective BOAT SIDE fuel system is.
1. Low WOT (Wide Open Throttle) rpms. (When the engine used to be fine)
2. Engine dies out when running at any rpm.
3. Engine surging at any rpms. more
However. this test can also be TRIED (and I can't stress the word TRIED enough) on the muffs, as long as you don't exceed 1500 rpms for more than a minute with good water supply.
This is CaptJason's rule. Don S. may have a different rule.
I say you can TRY it because on a lot of boats you'll see the gauge indicating a problem immediately. If the gauge does not indicate a problem immediatly. you should still go through the test with the engine under a load as previously stated. here
As with any special tool. Not everything will come in the box.You also need to make up some proper fuel hoses for YOUR boat. because EVERY boat is different. Most of the extra brass connectors and fuel lines/vinyl lines can be had in between NAPA auto part stores and home depot/lowes type stores. Since you probably won't be working on very many, get the right stuff and make your job easy and safe instead of difficult and dangerous. You will need specifically sized fittings that will fit the fuel pump, and or the boat side fuel line or tank. Don't even think about cutting that steel line and hose clamping a tee for the gauge to it. Steel line should not be cut. Besides, we are testing the BOAT SIDE fuel system, where steel line is almost never found. If you were TESTING THE ENGINE SIDE fuel system, there is often steel line (and should be) and this thread does not cover ENGINE SIDE fuel system testing.
To refresh
Gauge reading exceeds 4 in. of mercury (Hg)
Supply side of fuel system has a restriction. Check points of possible
failure as noted below.
1. Water or debris in fuel/fuel filter
2. Fuel pickup tube and screen blockage
3. Fuel tank vent blockage (this one can be a biggie. i swear. a mud doggers only purpose in life is to build nests in tank vents)
4. Plugged external canister or carburetor fuel filters
5. Inoperative, restricted or incorrectly sized anti-siphon valve
Repair or replace suspect part, then make another vacuum test to verify repair.
6. Bad fuel lines(uncommon) [links]
Problem No. 2-Malfuntion of Hose Check Valve more
A faulty check valve may be bypassed by utilizing the natural phenomenon referred to as a siphon. To accomplish this one would open the fuel tank and place the fuel hose (having removed its connector from the hose) directly into the gas. Now comes the difficult, and potentially dangerous, part. We not only don’t recommend this, but we strongly advise against using this technique. It is mentioned here strictly for informational purposes, as some professionals report using this technique. Siphoning gas can cause gas to enter your mouth and lungs and can cause serious injury and death! DO NOT siphon gas. That being said, professionals report placing the mouth on the engine end of the hose (which has been placed lower than the gas) and “sucking” fuel into the gas hose. Once the gas has passed through a portion of the hose the operator releases suction. Fuel then flows through the hose, priming it for connection with the engine. A quick pull of the paper clip would then make the engine connector end of the hose ready for attachment to the engine. The engine’s fuel pump would pull fuel, and the engine should run, as long as the tank end of the hose remains submerged in gas. here
This hand pump will only work if its arrow points in the direction of gas flow AND it is pumped in the "up" position (as shown)
Occasionally the connector attached to the gas tank, the one that connects to the gas hose connector, is faulty. The spring on the valve can be checked manually by simply pressing in its pin, which should move in and out with moderate pressure. If either this connector is faulty, or if the pick-up hose inside the tank is blocked, then a professional, at his own risk, may choose to bypass the tank system completely and siphon gas from the tank (see precautions above). [links]
#1 El Cheapo Type – The one in this photo is the style I refer to as the “El Cheapo”.. They are inexpensive and last just about as long a the flavor of the gum in a pack of baseball cards. I replace this style sender about 10:1 over the other types mentioned below.. If you have one like this, and it has failed, look into the other types shown in this article. [links]
In order to test your sending unit simply connect a DVM turned to the Ω setting to the center stud and ground reference. On this particular sending unit, from Moeller, ground reference is the flange or the male Fast On terminal I am connected to.
In this image the tank float arm is vertical or reading empty and we can see a near perfect 237Ω reading. This sender is reading empty just about perfectly. more
The fuel sender, for the typical US standard used in a marine application, is a simple device that presents a resistance reading to the gauge with which it is paired. For US fuel gauges, from the likes of Stewart Warner, Faria, Vee-Three, Moeller, Teleflex, Tempo, Westerbeke, Universal etc. this reading is 33Ω – 240Ω.
#2 WEMA Type The WEMA sender uses a float that rides up and down a sealed dip tube. No electrical components are inside the tank and exposed to fuel. They are very, very reliable. These senders are sold by WEMA (now KUS), the actual manufacturer, and re-labeled by companies such as Moeller and others.