SCOTT42

My Feedback: (1)

Ok so i just had the carb rebuilt, Ive got it installed with the weep hole lined up properlly, now every time I attempt to start it all it does is rev up and run at a high rpm for a sec or so, or it will pump too much fuel and vapor lock. I cant seem to get the needles set right and not real certain just exactlly where they need to be set at. I was told that the plastic spacer could be cracked from being over tighten, I havent checked it yet but will first chance i get. Any help would be very greatfull. Thanks Scott

karolh

Set both needles at 1.5 turns out for the initial startup and fine tune from there when the engine is properly warmed up. Is it the pulse hole in the carb isolator block and the carb that you refer to as a weep hole?

Karol

Antique

My Feedback: (4)

Yake the carb off the engine...Check the insulator block for cracks and see that the pulse passage is at the bottom..
Take both covers off..
Put the diaphragm with the two little flappers against the carb surface, put the gasket on top, then the cover..
Check to see that the lever that lifts the needle is flush to the casting next to it...FLUSH.
Put the gasket on first, then the diaphragm, then the cover...
Close the throttle ...Look into the carb from the side that goes against the engine..You should see the head of the screw that holds the plate on the shaft...If you see threads the lever on the end of the shaft is rotated wrong, change the lever on the outside end ..
Put the carb back on, it should work....
There is no weep hole, there is a pulse hole and a hole in the steel cover that puts atmospheric pressure on the diaphragm.
Vapor lock is when the carb gets hot and the gas evaporates inside.

graygoose

what size prop, too much prop will load it down ask me how i know,has the motor been sitting for a while??

SCOTT42

My Feedback: (1)

Ok I just pulled the carb off and checked the spacer for cracks and found none, ive got a 16-8 prop on it. what its doing is reving up real high when i try to start it and then it will die, or it will pump way to much fuel on top of the piston and ill have the remove the plug and drain it all out, and thats what i ment when I said it was vapor locking. Im at a loss on ideas here, Ive checked the needle settings and have them close to where they need to be, or so I think?

SCOTT42

My Feedback: (1)

Yes it has been sitting, 2 years.

w8ye

My Feedback: (16)

From this statement the metering valve side of the carb is not functioning correctly

The diaphragm is bad or the needle is sticking

Antique

My Feedback: (4)

A properly operating carb will not allow that much fuel into the cylinder..
Take the fuel line off...Connect a short piece of fuel line to the carb and blow into iit..If you can blow into it at alll the inlet needle is leaking...

SCOTT42

My Feedback: (1)

Im going to go try that in a moment, but would it or could it happen if you have the needles way out? Way to rich is what I mean.

SCOTT42

My Feedback: (1)

ok well I just went and put a new peice of fuel line on it and blew into it and I was able to blow thru it and could easlly hear it passing thru.

w8ye

My Feedback: (16)

The part of the carb under the steel cover is not working.

This is called the metering valve

This is a demand regulator that is not to let fuel pass through it unless flow through the carb creates a vacuum on the diaphragm and essentially asks for fuel. It takes a 2: water column vacuum to open it normally. It is a diaphragm operated needle and seat.

Yours is stuck open

Antique

My Feedback: (4)

The high an low needles have nothing to do with fuel entering the carb through the fuel fitting...Take the steel cover off and observe the inlet needle and lever when you blow into the carb..There's a small spring under the lever that keeps the lever pressing the needle onto the seat..Either the needle is stuck open or the lever is set way above flush to the casting and can't close it off...It takes at least 8 l bs pressure to blow the needle open, I guaantee no one can blow that hard....

SCOTT42

My Feedback: (1)

Ok so yesterday i took the plane over to the guy that rebuilt the carb, he is a small engine shop and works on nothing but small engines, i explained what its been doing, first thing he does is a compresion check on the carb,and its presureing up like it should and holding presure, he goes asfar as getting a walbro guage to check the meter valve and all checks out there like it should so we checked every thing else out, we had fire, we had fresh fuel, But we still cant get it to start, I have checked the timeing 3 times and it apeirs to be right on. Im at a loss here and just about to say screw it and spend the 60.00 that it would take to buy a new carb from horizen, and if that dont work then Ive got me a 400.00 paper weight! I took it off of the plane and mounted it on my work table so its easyer to work on.

ec121

My Feedback: (2)

If all that checked out, how did you hear the air coming out of the carb when you blew on the tubing? Had to come from somewhere. Try a little soapy water on the carb body and block and look for bubbles.