Throttle = Gas ???

[kimchee]

Excuse me for the quick stupid question, but I think some will benefit from the answer...

When we goto start a carb'd engine, or at least on mine, I pump the throttle 2 full times, and start with the throttle at 3/4 the way to full...
I think I got that from here... anyways, some have said that in some engines with choke issues or other issues, it may help to try and start the engine with the throttle wide open... and pull back once fired...

This is where it gets confusing... at least for me...
When we "move/pump" the throttle forward, it is releasing gas into the barrels.... fine, I get that part...
BUT, when the throttle is already "IN THE WIDE OPEN THROTTLE" position, is gas constantly being released into the barrels? I have always believed no...
and I believe the answer is NO.. can you please confirm?

As far as I know, the main reason for some of us to start with the throttle wide open is to keep the choke open, to allow for more air...

 

[kimchee]

Re: Throttle = Gas ???

Is there a need to pump the throttle 2 full times if the engine is already warm (ie. on the water, and was just running an 1 hour ago).

On is that just for when you are going to a cold engine?

 

[88wellcraft]

Re: Throttle = Gas ???

Usually just a cold engine.....I have a 4.3L with a cobra outdrive.

I pump throttle once to set the choke and start with throttle just over idle.

 

[kimchee]

Re: Throttle = Gas ???

thanks for the reply, but you didn't actually answer the question about whether or not there is gas being released when the throttle is wide open, asssuming I left the throttle wide open...

I guess a good analogy would be a car, when you are keeping your foot down on the gas (which I equate to leaving the throttle wide open) there is gas constantly being released. But I don't think this applies to boats... hence, the confusion...

Nevertheless, I humbly appreciate your response...

 

[Haut Medoc]

Re: Throttle = Gas ???

No, gas is not being constantly released with the throttle wide open-unless you are cranking the engine......
There should be no need for pumping when the engine is at all warm.....
2 pumps 1/4 throttle is what I do.....​

 

[kimchee]

Re: Throttle = Gas ???

Thanks, Question Answered...

 

[paulrfrancisco]

Re: Throttle = Gas ???

When the engine is cold, typically you pump the throttle for 2 reasons... The first one is to close the choke. At the same time when you pump the throttle hard like you describe you force the the accellerator pump to squirt a couple of shots of gas into the carburator. At this point you should be able to leave the throttle at about 1/4 and then crank... you may need to do some very slight pumping 1/4 -3/8th, 1/4- 3/8ths while cranking.

The purpose of leaving the throttle in a WOT position without pumping is to create the leanest condition while you are cranking, in case you are flooded. Once it fires up, quickly throttle down....

 

[paulrfrancisco]

Re: Throttle = Gas ???

Of course my above post is for manual choke and carburated engines... If its fuel injected, forget about everything I said.... the elctronics should take care of everything for you...

 

[bjcsc]

Re: Throttle = Gas ???

While Haut is correct, I think the technical answer to your question is "yes". You are describing leaving the throttle wide open while starting. Gas will be moving in during the starting, as Haut described. Remember how carbs work. The air moving through them is what brings in the gas - venturi - no air moving through = no gas. While cranking, you won't be moving much gas (which is why flooded engines start at full throttle as Paul mentioned) because you're not moving much air.

 

[kimchee]

Re: Throttle = Gas ???

... typically you pump the throttle for 2 reasons... The first one is to close the choke....

Damn, just when I thought the question was answered, I had to read a response like this... lol (I appreciate the response, but this confused me... again)

pumping the throttle closes the choke? really?

 

[Haut Medoc]

Re: Throttle = Gas ???

Yes.....​

 

[88wellcraft]

Re: Throttle = Gas ???

The choke is on...when the flaps are closed.

 

[Maclin]

Re: Throttle = Gas ???

Kimchee,

Pushing the throttle forward sets the choke (closes it) (also sets the fast idle) when the engine is cold...as Paul said. Pumping the throttle on a warm engine does nothing to the choke. Choke linkages work from a temp-sensitive device, ususally a bimetal coil. When the engine is (relatively) cold they close and as the engine warms up they open. The throttle linkage is setup so as to allow the choke to close only when the throttle is moved forward just past idle, then when pulling the throttle back it will be on fast idle, the choke will stay closed and open gradually as the engine warms up. Once the choke pulls full open the throttle will settle back to normal idle.

 

[kimchee]

Re: Throttle = Gas ???

But my problem is, is that, I am running too rich (too much gas)...
By moving the throttle forward (which sets the choke/closing it), doesn't that make my problem even worse?

and if so? What should I do?

Perhaps based upon your responses, I should only pump forward less than 2 full pumps forward, and experiment from there, when cold?

Therebye releasing less fuel into the barrels, and trapping a lesser quantity.

Arhh... BUT, when the throttle is WIDE OPEN, doesn't that mean it is allowing the MOST amount of air into the carb...? which is contradictory to "setting the choke/closing it"?

ARHHHHH, SO FRUSTRATING, please help the eagar learner... I assure you...
It is frustrating me, more than you....

 

[Coors]

Re: Throttle = Gas ???

I think your choke needs adjusting; it is set too tight.

 

[evilratgirl]

Re: Throttle = Gas ???

Kimchee, of the responses here Haut is the most correct.

The simple full stroke movement of the throttle pumps a shot of gas into the intake from the accelerator pump. It also sets the choke if cold as well as the high idle cam.

At this point, no other gas is going into the intake. That is until vacuum from cranking or starting the engine starts sucking gas thru the idle or metering holes, depending on the where the throttle is.

With the throttle closed or in the idle position, vacuum created by the running engine pulls gas thru the idle needle screws/holes which are below the throttle plates.

When the throttle opens there comes a point where the metering system takes over and the idle system becomes minimal.

The basic workings of a carb, be it your lawnmower or boat is really the same. The only thing putting gas into the intake without vacuum of the engine is the accelerator pump or bad float.

 

[Coors]

Re: Throttle = Gas ???

Check choke first?