choke function/operation question

joed · Mar 6, 2013

My understanding of how the choke works. You press in the key and it closes the choke flap. You continue to hold it in while you crank the engine. Let go as it starts.

What someone is telling me it does. You press in the key and the choke closes the flap AND it shoots gas into the carb as long as you hold it in. He tells me to choke the engine you press and hold the key for what ever time you want and then you let go and start the engine.

I think he is wrong or is that how it works on some engines?
Engine 60hp 1995 Mariner.

idonthaveaname · Mar 6, 2013

Re: choke function/operation question

The basic procedure is:

Push the key in, activating the choke plates or primer.
Turn the key to start.
After the motor begins to run, release the key so it returns to the run position and disengages the choke/primer.
As the motor begins to stumble, bump the key in activating the choke/primer. You may need to do this several times until the motor can fast-idle on its own.

You can read everything here

Chris1956 · Mar 6, 2013

Re: choke function/operation question

Well, the answer depends on whether you have a choke plate or an enrichener. A choke plate restricts air, richening the mixture. it is used on older OBs. An enrichener pumps raw fuel into the carb throats or intake manifold. These have no choke plates. These are used on newer OBs

Don S · Mar 6, 2013

Re: choke function/operation question

idonthaveaname said:
You can read everything here

Good info except he has a Mariner, not a Johnson or Evinrude.

The system is an enrichment system, there are no choke plates on the carbs.
This is a copy and paste from the manual on how the system works.

Enrichener System

The enrichener system provides the engine with extra fuel
charge for ease of starting cold engine. The system consists
of an electrically operated enrichener valve which is
connected by a hose to the intake manifold.
Fuel is gravity fed to the valve from the float bowl of the top
carburetor via a hose. When the ignition key is turned to the
“on” position and pushed in (and held in) current is sent to
the valve causing it to open, which allows fuel to pass thru.
The fuel passes thru a hose and is supplied to the engine
via fitting located in the intake manifold of the middle carburetor.
When the key (or choke button) is released, the valve
will return to the closed position. The valve can be operated
manually by pressing and holding button located at bottom
of valve.

joed · Mar 7, 2013

Re: choke function/operation question

So does my engine have a choke plate or enrichener system?

Engine 60hp 1995 Mariner. SN OG211531

Don S · Mar 7, 2013

Re: choke function/operation question

You have the enrichener system. I just forgot to properly say that was what you have.

idonthaveaname · Mar 7, 2013

Re: choke function/operation question

I wish I had an enrichener ... i could use the money. :facepalm: Maybe I will get lucky this week with Powerball.

That said...I have a 1996 Johnson 90HP. I push the key in, tap the ignition, motor starts. I am happy. :joyous:

Texasmark · Mar 7, 2013

Re: choke function/operation question

Charlie adequately described the system for the Mariner/Mercury. I have had choke systems and there is a definite brass plate immediately in front of the carb venturi, easily seen with the naked eye. Enrichment systems like I currently use, have no plate as they inject fuel, they don't reduce air flow to increase fuel to air ratio as a mechanical choke does.

Mark

MH Hawker · Mar 7, 2013

Re: choke function/operation question

I have had both and I like the enrichener better

aussieflash · Mar 7, 2013

Re: choke function/operation question

If you just push the key in,nothing will happen.You need to have key in "on" position first.I hold in for 5 secs then release and start engine.If you listen when key pushed in you can hear click from engine when valve opening.Dont forget to pump ball first....lol.

Laddies · Mar 7, 2013

Re: choke function/operation question

Well guys here I come complications the thread, Mercury has used 3 systems
1. The choke which is a plate in the carb throat that shuts increasing the vacuum and richening the fuel mix for start.
2 The enriching system which has a additional circuit in the carb to enrich the fuel mixture
3. The primer system which has a primer solinoid connected to a fuel supply outside the carb which when used lets fuel into the throat of the carb or reed block.
You have been misinformed as you have a primer system on your engine.

Wops, just looked in a newer manual and now the primer system is also called a enrichment system to so the misinformation you recieved was fron ME.

Texasmark · Mar 7, 2013

Re: choke function/operation question

Laddies said:
Well guys here I come complications the thread, Mercury has used 3 systems
1. The choke which is a plate in the carb throat that shuts increasing the vacuum and richening the fuel mix for start.
2 The enriching system which has a additional circuit in the carb to enrich the fuel mixture
3. The primer system which has a primer solinoid connected to a fuel supply outside the carb which when used lets fuel into the throat of the carb or reed block.
You have been misinformed as you have a primer system on your engine.

Wops, just looked in a newer manual and now the primer system is also called a enrichment system to so the misinformation you recieved was fron ME.

It's ok man. We'll get through this together.........somehow. Grin

Mark

joed · Mar 8, 2013

Re: choke function/operation question

OK found this in an online manual.

The electrically operated fuel primer valve
provides additional fuel for easier cold starts.
Fuel is gravity fed from the top carburetor (or
pressure fed from the fuel pump) to the fuel
primer valve. When the ignition switch is held in
the CHOKE or PRIME position, the valve opens
and allows fuel to flow to the carburetor(s),
intake manifold fitting(s) or balance tube(s), depending
on model. The valve can be operated
manually by depressing and holding the button
located on the valve. Typical fuel primer valve
system hose routing is shown in Figures 44-46.
Refer to Chapter Three for electrical troubleshooting
procedures.

I'm going to have to look at this when the boat comes out in the spring.

choke function/operation question

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