how would i check for all those things?
Starting it up is a whole other problem. there doesnt seem to be a pull of fuel to the crab so sometimes i have to take off the air filter and pour some gas in that way. Could that be a vacuum leak and is loss of power a symptom of a vacuum leakage?
Begin by physically inspecting all of your rubber fuel lines between the tank(s) and carburetor for cracks and/or loose connections. Make sure clamps are installed and snug where hoses slip onto metal fittings.
Procure the proper
gauge (pictured below) and measure fuel pump pressure (5 - 7 PSI), fuel pump vacuum/suction (>20" Hg), and fuel pump delivery/flow (>1 qt in 30 seconds of cranking).
Be very careful when working with the fuel system, especially when checking fuel pump delivery. Avoid all sparks or flames. Insist on help from a level-headed assistant; don't work alone. Have a fire extinguisher handy and make sure both you and your assistant know how to use it! Have rags available to immediately wipe up any fuel that spills or leaks. Enriched fuels are very flammable and can cause severe chemical burns, so BE CAREFUL!To check fuel pump pressure:
Connect the
fuel pressure gauge according to the instructions supplied with the gauge, directly to the fuel line leading to the carburetor. Have an assistant crank the engine for ~7 seconds while you watch the gauge and record the reading. If pressure was below 5 PSI, replace the pump.
To check fuel pump suction:
Remove and plug the 3/8" fuel supply hose that comes from the fuel tank from where it attaches to the fuel pump. Be careful of fuel that may siphon from the tank or drain from the pump. Connect the
vacuum gauge directly to the 3/8" fuel pump nipple. Have your assistant crank the engine for several seconds while you watch the gauge and record the reading. Reconnect the tank supply line to the fuel pump. If suction was less than 18" Hg, replace the pump.
To check fuel pump delivery:
Verify that the fuel line coming from the tank has been properly reconnected to the 3/8" nipple on the fuel pump. Verify there is adequate fuel in the tank. Remove the fuel line from the carburetor and direct it into an "empty" one-gallon container, such as a gasoline can or an old antifreeze bottle, etc. You may need to extend the fuel line with a rubber hose to reach the container safely; be mindful of any fuel that may or could potentially leak or spray, to minimize the risk of fire and injury. Have your assistant crank the engine for 30 seconds while you carefully direct the flow of fuel into the container. Reconnect the fuel line to the carburetor, wipe up any spilled fuel, then measure the amount of fuel pumped into the container. If fuel delivery was less than 1 quart in 30 seconds of cranking, replace the fuel pump.
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