electric choke

P

Pbarrett2

Recruit
Joined
Jul 5, 2018
Messages
5
I can't find an exact description of what a normal choke does in operation. I understand how it is supposed to do to start cold engine but what exactly closes it? Is it still open from the last use when I come out to it? what action closes it? key on or start? throttle forward and back once? in what sequence? would it be closed before I do anything when it is cold? I think it is NOT going closed but the carb part the electric wire goes into the choke gets warm.
 
ahicks

ahicks

Captain
Joined
Sep 16, 2013
Messages
3,957
More info on what sort of engine we're talking about necessary. Outboard vs. inboard, carb vs. injection, and age can all make huge differences with that you have going on, and there's little common ground among them - other than they are generally used to start a cold engine.
 
GA_Boater

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
Pbarrett2 said:
I can't find an exact description of what a normal choke does in operation. I understand how it is supposed to do to start cold engine but what exactly closes it? Is it still open from the last use when I come out to it? what action closes it? key on or start? throttle forward and back once? in what sequence? would it be closed before I do anything when it is cold? I think it is NOT going closed but the carb part the electric wire goes into the choke gets warm.
Click to expand...

What motor are you choking?
 
C

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,074
In general, older outboard carbs have a solenoid which closes the choke plate, when the choke button is pressed. Newer outboards have an enrichener valve which dumps raw fuel into the motor, when the choke button is pressed.

Older Rochester carbs on Mercuriser I/Os had an automatic choke, operated by air and electric. They used both manifold-heated air and an electric heating element to open the choke plate, as the engine warmed.
 
4

444

Senior Chief Petty Officer
Joined
Jul 16, 2010
Messages
704
Chris1956 said:
In general, older outboard carbs have a solenoid which closes the choke plate, when the choke button is pressed. Newer outboards have an enrichener valve which dumps raw fuel into the motor, when the choke button is pressed.
Click to expand...

To expand on this a little, on older outboards, when you hold the choke button, a flapper door closes off the air flow to the carb. You can usually hear the flapper closing and opening when push the choke button and let off the button. By restricting air flow to the carb, the engine draws in more fuel when cranking (think suction on a vacuum cleaner when you cover part of it with your hand). Sometime in the 80's most outboards went to a fuel enrichment valve so instead of closing a flapper door to restrict air, a valve in the carb opens to provide extra fuel during cranking. With both of these systems you have to hold the choke button down when cranking then let off once it fires. Small kicker outboards may have a lever or pull cable to actuate the choke, this one you don't have to hold as the lever stays where you left it.
 
You must log in or register to reply here.
Top