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View Full Version : Holley 4160 choke fast idle.


climbinggod
08-11-2008, 09:26 PM
Hi all,

I have a new 4160 Holley carb. The problem I have is that when the engine is cold with the choke in the closed position, the engine does not idle fast and thus keeps stalling. I followed the Holley Carb adjustment instructions on this forum but couldn't find the screw to adjust the choke idle speed. Anyone any ideas???38919

Skipper
08-12-2008, 09:59 AM
Looking at the instructions you should be working with the "fast idle screw" on page 6.

FAST IDLE SCREW:
The fast idle screw works in conjunction with the choke by setting the idle
speed while warming up. If your engine idles fine when its warm, but to fast
or too slow when cold, then this screw will need adjustment. Use the engine
service manual for your vehicle to set the rpm. Here are the proper steps for
setting the fast idle.

1. Check the choke tension. The choke must not stick and should work
smoothly. If it doesn’t, it will cause high idle speeds.
2. With the engine warmed up and the air cleaner off, turn off the engine.
3. Holding the chock butterfly closed with one hand, partially open the
throttle and let it close.
4. Release the choke butterfly. This will position the choke fast idle cam
in Figure 12
the cold start position.
5. Start the engine without moving the accelerator pedal or throttle.
6. The engine should start and idle at approximately 2000 rpm. If not, the
fast idle screw should be adjusted until it does.
7. Move the throttle, the choke should open and the engine should return
to normal idle.

Hunterb
08-12-2008, 02:55 PM
If you have a Holley Marine 4160 carb on there then there is no fast idle screw or adjustment possible. The 4160 has an electrically operated choke plate that closes when the key is turned on and the engine is cold. That plate will gradually open, even if the engine isn't started, as it has a heating element built into it. The purpose of the choke is to provide a richer mixture by restricting the air flow. The choke mechanism does not have a fast idle cam, unless someone has added it or you have a street carb on your boat. If you want a fast idle you must advance the throttle manually. The carb's are designed this way to prevent boats from being put into gear with the engine revving higher than idle speed which would cause people to ram docks, trailers, other boats etc. If your boat is stalling when cold you may well have a carb problem, but there is no fast idle adjustment, and you definitely don't want a fast idle anyway. There are people that think they are 'setting the choke' by pushing the throttle prior to starting but they're not, unless someone has added parts to the carb that shouldn't be there. 4160 carb's for road vehicles will have a fast idle set up, but not for boats.

I would suggest you start out by making sure you carb is set up properly and then see how it runs. If it's stalling when cold it may be a mixture problem, or a number of others.

Not sure if that helps. Good luck with the boat.

Bruce

T-Rager
08-12-2008, 06:08 PM
If you have a Holley Marine 4160 carb on there then there is no fast idle screw or adjustment possible. The 4160 has an electrically operated choke plate that closes when the key is turned on and the engine is cold. That plate will gradually open, even if the engine isn't started, as it has a heating element built into it. The purpose of the choke is to provide a richer mixture by restricting the air flow. The choke mechanism does not have a fast idle cam, unless someone has added it or you have a street carb on your boat. If you want a fast idle you must advance the throttle manually. The carb's are designed this way to prevent boats from being put into gear with the engine revving higher than idle speed which would cause people to ram docks, trailers, other boats etc. If your boat is stalling when cold you may well have a carb problem, but there is no fast idle adjustment, and you definitely don't want a fast idle anyway. There are people that think they are 'setting the choke' by pushing the throttle prior to starting but they're not, unless someone has added parts to the carb that shouldn't be there. 4160 carb's for road vehicles will have a fast idle set up, but not for boats.

I would suggest you start out by making sure you carb is set up properly and then see how it runs. If it's stalling when cold it may be a mixture problem, or a number of others.

Not sure if that helps. Good luck with the boat.

Bruce

What Hunterb said in correct. Their is no fast idle mechanism on the marine 4160.

TMCNo1
08-12-2008, 08:15 PM
You can always pull the button under the shift lever with the lever in neutral, putting the gear shift/throttle lever in throttle only and increase the rpm after it gets running either forward or backwards to give it a fast idle till it warms up, then go back to neutral, push in the button and proceed as normal. That is one of the reasons the button is there. That's all we've ever used for a cold start high idle for nearly 20 years on our '89.

It explains it quite simply, how to crank your cold engine in the "Knowledge Center", "Owners Manuals", '91 to '93 ProStar, page 17, paragraph 3 and 4, here, http://www.mastercraft.com/files/manuals/1991_1993_Prostar_Manual.pdf (http://www.mastercraft.com/files/manuals/1991_1993_Prostar_Manual.pdf)