Pulse fitting

[EvhCo]

Is the "neck" of the carburetor on a nitro engine good for mounting a pulse outlet? It is to be used with a Walbro carburettor.

 

[cbaker65]

Is the "neck" of the carburetor on a nitro engine good for mounting a pulse outlet? It is to be used with a Walbro carburettor.

Are you talking about a gas carb that has the fuel pump diaphragm in it?

 

[EvhCo]

Are you talking about a gas carb that has the fuel pump diaphragm in it?

Yes.

EDIT: I might not have explained myself correctly. I'm talking about the neck of the engine's intake, the one in which you'd slide the carby. Let me worry about mounting the Walbro, I just need to know if I can get pulse from the aforementioned position on the engine.

 

[cbaker65]

Yes.

EDIT: I might not have explained myself correctly. I'm talking about the neck of the engine's intake, the one in which you'd slide the carby. Let me worry about mounting the Walbro, I just need to know if I can get pulse from the aforementioned position on the engine.

I'm not sure if the nitro engine will have enough draw in suction to operate a diaphragm carb.!
But gas also creates its own pressure if its in a sealed tank ,so you will have to have a breathable tank!
The only way to check , is to put your finger over the throat of the engine to see if it has some good
draw in suction!
You might can install like a boost port off the engine to one of the nipples on the carb ,probably ,
to the primer bulb nipple!

 

[EvhCo]

I was afraid you'd be right . Doesn't look like there's any suction off the carb.
My carb doesn't have a primer, instead it has a built-in pump pulse inlet nipple, which is why I wanted to use this particular one.
Any other way I can generate pulses for the carb? If not, I think I'll go with an electric pump-or simply place the fuel tank higher than the carb. Ideas are welcome (and desperately needed).

 

[cbaker65]

I was afraid you'd be right . Doesn't look like there's any suction off the carb.
My carb doesn't have a primer, instead it has a built-in pump pulse inlet nipple, which is why I wanted to use this particular one.
Any other way I can generate pulses for the carb? If not, I think I'll go with an electric pump-or simply place the fuel tank higher than the carb. Ideas are welcome (and desperately needed).

The carb doesn't have a second brass nipple coming out? ,I know some of the older ones didn't!
I have a bunch of carbs. ,carbs are cheap ,a few bucks use in the outdoor power equipment section.
I am always there sense I fix other peoples lawn equipment on the side!
https://www.ebay.com/itm/Carburetor...e=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649

 

[cbaker65]

If theres not quite enough pressure ,you might can open up the needles more ,enough to get fuel flow ,an
let the fuel pressure built up in the tank to do the rest ,I know that pressure can be built up in the tank if its not
ventilated!

 

[EvhCo]

So fuel builds up pressure by itself when the engine's running? This applies to gasoline or nitro as well?
I remember that when my old GX15 wouldn't prime, I would cover the carburetor and crank it. The fuel would rush to the carburetor blinding fast when I did that.

 

[cbaker65]

So fuel builds up pressure by itself when the engine's running? This applies to gasoline or nitro as well?
I remember that when my old GX15 wouldn't prime, I would cover the carburetor and crank it. The fuel would rush to the carburetor blinding fast when I did that.

On nitro ,the fuel pressure comes from the pressure tube off the muffler to the tank ,but once fuel
flow starts ,it can siphon on its own.

Regular gas fuel will build up pressure on its own just sitting in a sealed container ,that's why weedeaters or
anything that runs off of gas has to have some kind of ventilation ,otherwise ,it can an will get vapor lock.
The two stroke engine tank usually has the a oneway air vent part either in the tank lid or coming out of
the tank on a piece of fuel line!

 

[cbaker65]

It is possible that you can use tank pressure on a sealed tank for fuel flow ,but on a diaphramed carb. ,
too much pressure can freeze the diaphragm to not move to open the needle for fuel flow!

You might can use a nitro carb. if the needle settings are set right an the pressure in a sealed tank!

 

[cbaker65]

Gas fuel gives off vapors that create its own pressure ,so much so that if the tank is not ventilated ,
a diaphragm carb. is useless!
So that's why I suggest trying the nitro carb. ,all it does is meter the flow of fuel ,you just
have to adjust the amount of fuel in tuning the needles!

Old hit & miss engines didn't even have throttle ,the engine was revved up by simply turning a
needle to allow more fuel flow for more RPM's!

 

[EvhCo]

Alright. Here's the plan.
My carb also has two frontal ports above and below the throttle valve, probably used to bring in the carb's pressure to the pump, assuming the optional pulse inlet isn't used. I'm gonna make sure the mount is big enough that those ports are exposed to the crank, and hope that the engine's pressure is enough to man the pump.
If that don't work...I'll sort it out .
Thanks for the help!

 

[cbaker65]

Alright. Here's the plan.
My carb also has two frontal ports above and below the throttle valve, probably used to bring in the carb's pressure to the pump, assuming the optional pulse inlet isn't used. I'm gonna make sure the mount is big enough that those ports are exposed to the crank, and hope that the engine's pressure is enough to man the pump.
If that don't work...I'll sort it out .
Thanks for the help!

I have a box of carb.'s ,I will take pics of them an show you the different types I have!
You are more than welcome to have a few of them for your experiment for free ,but
you will have to pay the small SH. fee through pay pal!...

 

[EvhCo]

I have a box of carb.'s ,I will take pics of them an show you the different types I have!
You are more than welcome to have a few of them for your experiment for free ,but
you will have to pay the small SH. fee through pay pal!...

Hehe, well I appreciate your help very much, but I'm sure it would be more than worth the hassle to ship a few carburetors all the way to Southeastern Europe. I've got a few old chainsaws in the back, so maybe I'll pay them a long-awaited visit if I'll have to get a new carb.

I'm close to finishing the carb mount now, looks pretty good so far. I'll keep posting my progress here, and hopefully I'll have the engine burning gas until Christmas!

 

[cbaker65]

Hehe, well I appreciate your help very much, but I'm sure it would be more than worth the hassle to ship a few carburetors all the way to Southeastern Europe. I've got a few old chainsaws in the back, so maybe I'll pay them a long-awaited visit if I'll have to get a new carb.

I'm close to finishing the carb mount now, looks pretty good so far. I'll keep posting my progress here, and hopefully I'll have the engine burning gas until Christmas!

Ok no problem ,didn't know that you were across the drink!...

Years ago when I started my own yard care business ,I had to learn real quick how to repair an actually
build my own lawn equipment!
I use to go down to the local small engine repair shop an the owner use to sell me his old junk that
people left an didn't pick up ,yea ,like a small engine junk yard ,that's where I bought a lot of stuff
an accumulated a lot of parts ,bought a lawnmower there for 20 bucks 20 yrs ago ,an I still use it today!

Since about 4 yrs ago ,he closed up shop an retired ,I sure do miss him & his junk yard!

Now everyone comes to me ,because there is no other repairmen for small engines
with in 25 miles!....

So ,if you have a repair shop like that ,ask them if they got a junk pile out back!..

 

[EvhCo]

Ok no problem ,didn't know that you were across the drink!...

Years ago when I started my own yard care business ,I had to learn real quick how to repair an actually
build my own lawn equipment!
I use to go down to the local small engine repair shop an the owner use to sell me his old junk that
people left an didn't pick up ,yea ,like a small engine junk yard ,that's where I bought a lot of stuff
an accumulated a lot of parts ,bought a lawnmower there for 20 bucks 20 yrs ago ,an I still use it today!

Since about 4 yrs ago ,he closed up shop an retired ,I sure do miss him & his junk yard!

Now everyone comes to me ,because there is no other repairmen for small engines
with in 25 miles!....

So ,if you have a repair shop like that ,ask them if they got a junk pile out back!..

Small engine junk yard? Now that's my kind of heaven!

There are such places around here, too, I'll pay them a visit soon. Thanks for the tip!