Instructables

mower will only run if I spray starter fluid in air intake hole Any ideas Maybe clogged somewhere?????


framistan3 years ago
Old gas leftover from last year will not run the engine. Put new gas in. Also, the carb has a little valve that is activated by the float. The bottom of the carbeurator must be removed to access the little valve. When you find the little needle valve inside the carb, you will probably see it is not moving up and down with the float because of a little bit of dirt or rustyness on its surface. Clean it up so it slides up and down easily again then re-assemble everything. To remedy this, be sure your lawnmower is ALWAYS covered up and not left out over the winter. Rain and snow cause water in the gas and the needle valve gets water on it and it rusts up over the winter. I have fixed several lawnmowers this way.
As was asked of you in your last question, what brand of engine do you have? It should be labeled prominently.

Next question: is the carburetor fed from a remote tank (has a "rubber" fuel line going to it) or is the carburetor bolted directly to the top of the fuel tank? This makes a difference on how to help you in certain steps.

With that out of the way, let's get to what we can help you with. Your description of the problem says that you cannot get any/enough fuel into the engine to make it run. You have verified that the engine does run by spraying fuel into the air cleaner stack, so you have spark and the flywheel key is at least in fair shape (Frollard's question). Now, check for water in your fuel tank. If you shine a flashlight into the fuel fill hole, and gently slosh the tank around, you'll see the water as a "bubble" at the bottom. Also, it should smell like gasoline, not laquer. If it smells like laquer, the fuel is bad and needs to be replaced.  While you are looking, check for visible gunk, debris, and if it is a metal tank, rust. If you see anything other than gasoline in the tank, you have to clean it out. You can save the gas by putting several paper towel layers over the top of a gas safe container and securing the sides with rope, twine or large rubber bands. The paper towels acts as a filter and will let most of the gas through while keeping the water and debris away. If all you had was water, reconnect the tank and fill with fuel and try to start the engine. See this question for my megachoke method of priming the carb. If you had other gunk or debris in the tank, you will have to clean the carb which most likely will entail taking it apart, cleaning it, and putting it back together again. If you are unsure you can do that, take it to someone who can.

Another thing to check is the compression. When turning the engine, do you feel the resistance you felt the last time you tried to start the engine? Does it sound the same? If it spins easily, with very little resistance, you have a compression leak somewhere. Take a look at the previously linked question and you should find some help there.

Good luck and let us know what you find.

Qa
AndyGadget3 years ago
 
Could be water in the fuel as suggested, or a build-up of grot in the fuel lines or jet.  If it's got a gauze fuel filter then that would be prime suspect.  Take the fuel system apart and and make sure it's clear all the way through, and also flush out the tank as there will probably be more gunge waiting to do the same thing again.
rickharris3 years ago
What sort of engine is it - If it's a BRiggs and Stratton - or a copy - them most likely the rubber diaphragm under the carb body is punctured. this acts as a sort of fuel pump. Easily replaced but you need to carefully remove the carb from the fuel tank to get to it.

A lot of small 4 stroke engines use this type of construction.

other wise you may well have a blocked carb jet.
Vyger3 years ago
water in the fuel, check the other answer and try it . If that is not the problem then we try something else.
frollard3 years ago
So...first time you asked wasn't good enough?
orksecurity3 years ago
Sounds like it isn't getting fuel.