What does the choke do on a Suzuki EFI??

[Captain Caveman]

My 2009 Suzuki DF90A was on the fritz this weekend. I was 20 miles away from my cabin when the low voltage alarm went off. It turned over but wouldn't start, tilt/trim wouldn't work, etc. I disconnected everything from the battery, cleaned all of the connections, tightened everything, squeezed the fuel bulb, checked all of the fuses, and got it to fire and went the 20 miles home. The voltage meter was pegged at 14. As I approached my dock at idle speed the motor died.

I charged the starting battery that night but the next day but it still turned over without starting. While diagnosing, I decided to try the choke lever. If I pulled it up, my motor would start and idle wildly. At half "choke" it settled down but if I put the choke lever all the way down, the motor would shut off. Since you can't shift into forward or reverse with the choke lever up, I basically had a motor that would idle but go nowhere.

I used my electric trolling motor to get it back to the public landing and onto my trailer. I threw a new marine starting battery in but it still wouldn't start. Now it's at the shop to get diagnosed.

Long story short, what does the choke do? The dealer originally advised not to use it because it is an EFI - which made sense. I've never touched it in 12 years of use. Now that I see it was the only way to get the motor to start in a no-start situation, I am curious. What is that choke lever actually doing with my EFI motor?

 

[99yam40]

there is no choke on an EFI motor.
you might be thinking of a fast idle lever on the controls that just opens the throttle some with the motor in neutral

 

[racerone]

As stated it is a THROTTLE only lever.----

 

[Captain Caveman]

Looked at a few parts diagrams and you're right, it is a fast idle lever. I always assumed it was a manual choke to close the butterfly on carbureted motors. That is why I was confused as to why it did anything on my EFI. Now I know that it is an idle lever.

Case solved. Much obliged!

 

[racerone]

No it was never used as a choke as far as I know.----Just a fast idle lever.

 

[99yam40]

Looked at a few parts diagrams and you're right, it is a fast idle lever. I always assumed it was a manual choke to close the butterfly on carbureted motors. That is why I was confused as to why it did anything on my EFI. Now I know that it is an idle lever.

Case solved. Much obliged!

manual choke levers were on the motor itself, incase the electrical part failed to work. carbed motors only

 

[ct1762@gmail.com]

any EFI motor that i'm aware of uses an electric fuel pump to pump fuel in, thus priming the motor upon activation. the ECU probably bumps timing up a few degrees automatically when the temp sensor tells it it's cold. could be fouled plugs, or clogged injectors too.

 

[Captain Caveman]

The dealer talked with Suzuki techs and have narrowed it down to a faulty IAC (idle air control) valve, that led to fouled plugs and other issues. I'm waiting for them to get a new IAC installed.

 

[99yam40]

maybe if the IAC fried while in the mostly closed position and then did not open up to let enough air in during the start up process the motor would not start due to too rich mix.
opening up the throttle with the lever allowed it to fire up but at way to high of RPM and no way to control it well at lo idle

 

[Captain Caveman]

That's exactly what I was thinking, because normally the IAC shouldn't affect startup unless it died and stayed well below the 60% open position.

 

[Captain Caveman]

I got my boat back with the old IAC valve. It is stuck in the closed position when I try sending electricity through it. It is running great again, starting without issue.....Case closed.

 

[99yam40]

I got my boat back with the old IAC valve. It is stuck in the closed position when I try sending electricity through it. It is running great again, starting without issue.....Case closed.

why is it starting and running OK if the IAC is stuck in the closed position?
How are you trying to sending Electricity thru it?
It is a stepper motor, so you cannot make it work properly by just giving it 12 volts.

 

[Captain Caveman]

I didn't write that very well. My boat motor has the new IAC valve in it, so it is starting and running great now.

The shop gave me the old IAC valve. That's what I was trying to send 12v through on the bench. You are right. I can't make it properly work.