Engine Choke Question

[JimB77]

My 1995 Nitro 170-DC Tracker with a Mercury Mariner Tracker Pro Series 60 engine has a key/choke ignition switch which activates the choke when I push-in while the key is in the Start or Run position. I have no idea how this works and would appreciate some clarification.

I assume the engine uses electronic fuel injection rather than having a carburetor with a choke plate that closes. I've heard several suggestions for starting the engine:

(1) push in the key and hold to choke for 5 seconds before you crank the engine.

(2) crank the engine while holding in the choke till it fires.

(3) turn the key to the on position, bump the choke 5 times, turn the key and crank the motor while bumping the choke 2-3 more times.

(4) if the engine sputters after you let go of the choke, punch it in again until it smoothes out.

These all sound reasonable but I am open to suggestions for the best method to start the engine. The primary question here is: do I push and hold for 5 seconds or bump it five times? When you hold the key in does gas squirt continuously or do you get one squirt each time you push in the key? Thanks for any clarification you can give me.

 

[B-Magnum]

Good question, interested in the responses. I have a 1998, same choke and seems to work but haven’t used it but once. Just bought it three weeks ago and will finish getting everything ready to roll tomorrow and take it out Friday for my maiden voyage.

 

[olefisherman456]

for my 95 nitro i use a combination of 2 and 4 . I' m sure the choke stays on as long as the key is depressed.my 60 horse merc has carbs. and oil injection.

 

[Larry Williams]

My 1995 Nitro 170-DC Tracker with a Mercury Mariner Tracker Pro Series 60 engine has a key/choke ignition switch which activates the choke when I push-in while the key is in the Start or Run position. I have no idea how this works and would appreciate some clarification.

I assume the engine uses electronic fuel injection rather than having a carburetor with a choke plate that closes. I've heard several suggestions for starting the engine:

(1) push in the key and hold to choke for 5 seconds before you crank the engine.

(2) crank the engine while holding in the choke till it fires.

(3) turn the key to the on position, bump the choke 5 times, turn the key and crank the motor while bumping the choke 2-3 more times.

(4) if the engine sputters after you let go of the choke, punch it in again until it smoothes out.

These all sound reasonable but I am open to suggestions for the best method to start the engine. The primary question here is: do I push and hold for 5 seconds or bump it five times? When you hold the key in does gas squirt continuously or do you get one squirt each time you push in the key? Thanks for any clarification you can give me.

on older engines, holding the key in would cause the choke plate in the carburator(s) to close activating a solenoid that closes the choke (plate inside thethroat of carburators that block air intake from the vacum pressure created by the engine rotating (turning over)- plate(s) remain closed as long as the key is depressed. It is the engine turning over under battery power that begins the fuel flow (vacum pressure) without thad there is no fuel flow. You will be able to determine fairly quickly which details work for your particular engine to start it quicklky. Once a process works well just continue doing exactly that each cold start. Most engines don't need to be choked after the first start of the day. Newer engines have more complicated electronic systems (fuel injection) that provide the richer fuel mixture briefly to easily start a cold engine. Some variation of number 2 in your list is what I would expect to work best on an older engine. The less you have to re-engage the starter motor the better. I have probably missed some other points here but hope this helps a little.

 

[jerry shack]

For those years of outboards the choke system is a valve called a enricher. It is a electric pump valve that squirts a shot of fuel into the intake manifold to get the motor to fire. It gets the fuel from one of the bowels of a carb. That's why you should always prime the ball first. So # 3 comes close but you are going to figure out what works for that motor.

 

[HAIRLESSxWOOKIE]

I have the same outboard on my NX750 but its a 90hp not 60hp. Same mechanics though. The motor is carbureted not fuel injected so the "Choke" as mentioned above is a fuel enricher that basically shoots a small amount of gas straight to the intake. I usually prime the ball until its rock hard, turn the key to the "ON" position and hit the enricher 4-5 times the then fire up. If my motor starts to die I hit the enricher once or twice to get the RPMS back up. Works fine for me after initial fire off in the morning I never have to hit the choke again. If you hold the enrichment valve open it will continuously flood the carburetors and intake, the these motors can be a bit temperamental if flooded.

 

[JimB77]

These are very interesting and authoritative replies. Very helpful information. Thank you very much to everyone who took the time to answer my inquiry.