066 not getting gas -> cylinder, won't start

[Michael G]

Compression: 150psi
Spark: Yes

Gas pumps up through the fuel line, but it seems like it won't get to the needles. Pulled my plug and it was totally dry.

This is first 066 carb I've dived into. Here are some images, maybe you can spot something my eyes aren't trained to see.

 

[backhoelover]

if you have a bad air leak the impulse of the engine will not work the pump diaphragm to pull fuel for the tank. also need to check the inpulse tube

 

[backhoelover]

impulse also runs the metering diaphragm

 

[Michael G]

impulse also runs the metering diaphragm

Gave my impulse line a good look, nothing there.

 

[blsnelling]

if you have a bad air leak the impulse of the engine will not work the pump diaphragm to pull fuel for the tank. also need to check the inpulse tube

It would still start with the choke.

 

[Michael G]

I would still start with the choke.

Excuse my asking but what does choke have to do with gas not even getting into the Venturi?

 

[jmssaws]

I would still start with the choke.

 

[jmssaws]

Excuse my asking but what does choke have to do with gas not even getting into the Venturi?

If the choke isn't working you will never get it started.
If you didn't need the choke to get gas to the venturi then there's no point in a choke period.
I bet the arm on the master control is broke off.

 

[Michael G]

If the choke isn't working you will never get it started.
If you didn't need the choke to get gas to the venturi then there's no point in a choke period.
I bet the arm on the master control is broke off.

The choke arm is there and it does choke.

 

[alexcagle]

If you can squirt gas in spark plug hole and it fires and then dies with the plug installed, but then won't pull gas in through the carb, then it may be either the intake boot, a crank seal, or base gasket leaking badly.

 

[jmssaws]

Even with a giant airleak it should still hit on choke.
Metering arm way to low?
Pump and diaphragm in correctly?
Pump then gasket
Gasket then diaphragm

 

[alexcagle]

That's a Chinese carb, right?
Is this saw new to you?

 

[Michael G]

That's a Chinese carb, right?
Is this saw new to you?

The saw is new to me. Got it on a steal so I really couldn't care what was in it as long as has compression.

Noticed it was Chinese carb, but I've had good luck with them in the past.

 

[jmssaws]

The saw is new to me. Got it on a steal so I really couldn't care what was in it as long as has compression.

Noticed it was Chinese carb, but I've had good luck with them in the past.

How many times did you pull it with the choke on?
It can take a while to prime a dry carb,was there has in the carb when you took it apart?

 

[Michael G]

How many times did you pull it with the choke on?
It can take a while to prime a dry carb,was there has in the carb when you took it apart?

Pulled it many times, enough that gas should have made it.

Gas pumps up the fuel line to the bottom of the carb but does no further than that. Nothing in the top

 

[grizz55chev]

Pulled it many times, enough that gas should have made it.

Gas pumps up the fuel line to the bottom of the carb but does no further than that. Nothing in the top

A vacuum pressure check should tell the tale.

 

[jmssaws]

It's a bad carb.
If it's pulling gas to the pump side and not to the diaphragm side there's nothing else it can be.
If the diaphragm is hooked or installed right and the metering arm is flush with the carb body then there's nothing else it can be.

 

[blsnelling]

Put a good carb on it.

 

[Michael G]

I got a new Walbro carb coming.

I was thinking down to the three, crank seal, impulse, or carb.

But yes gas it pumping so it should at least crank pop for a second (if carb can transfer gas).

Will wait for new carb and see how it goes. Thanks guys.

 

[Bwildered]

The L & H Jet screws could be wound all the way in or the jets blocked completely, fuel down the spark plug & see if it fires is the first step to solve the puzzle.
Statinski