Fixed one thing in Holley carb....now another problem with idle

[Scott Danforth]

With motor in water ( not muffs), and warmed up. Back out both idle mixture screws the same amount until RPM's get as high as they can, then back each out about 1/8th turn each to richen it up just a bit. Then adjust the throttle position until correct RPM is reached

 

[Surfnsnowboard3]

With motor in water ( not muffs), and warmed up. Back out both idle mixture screws the same amount until RPM's get as high as they can, then back each out about 1/8th turn each to richen it up just a bit. Then adjust the throttle position until correct RPM is reached

Got the first part. For the second part "adjust the throttle position until the correct RPM is reached." This referring to adjusting the single curb idle screw until it gets in the OEM recommended idle RPM (which is 650-700 for my boat)? So basically start the engine with the idle mixture screws all the way in. Start backing them out slowly and evenly until I get the highest RPM. Then out another 1/8 turn after that. Then once that's set, adjust the curb idle screw back down to 650-700? Doing all this with a warm engine and boat in the water and boat running in neutral?

I miss anything? I can do this!

 

[Scott Danforth]

Got the first part. For the second part "adjust the throttle position until the correct RPM is reached." This referring to adjusting the single curb idle screw until it gets in the OEM recommended idle RPM (which is 650-700 for my boat)? So basically start the engine with the idle mixture screws all the way in. Start backing them out slowly and evenly until I get the highest RPM. Then out another 1/8 turn after that. Then once that's set, adjust the curb idle screw back down to 650-700? Doing all this with a warm engine and boat in the water and boat running in neutral?

I miss anything? I can do this!

you cant start the motor with the idle mixture screws all the way in. the motor would not get fuel and it would not run. you start with them about 1-1/2 turns out.

 

[Surfnsnowboard3]

you cant start the motor with the idle mixture screws all the way in. the motor would not get fuel and it would not run. you start with them about 1-1/2 turns out.

That's right. I remember that now. Other than that, everything else sound right?

 

[Surfnsnowboard3]

I need more help. I've been trying to fix this for three days and with a newborn, I'm having a hard time...plus my wife is ready to kill me for working on the boat so much, leaving her with our newborn.

Here is the instructions from the OEM manual:

1. Back the idle speed screw out until it just rests on the idle cam, but not moving it.
2. Back out both idle mixture screws 2.5 turns from all the way in.
3. Put flame arrestor on
4. Use seperate tach from boat
5. Start engine and get it to operating temp
6. Disconnect throttle cable because the boat will need to be in gear
7. With the engine running and throttle lever disconnected, move the lever into forward and turn the mixture screws clockwise slowly until the engine speed JUST begins to drop. Jot down the number of turns.
8. Now back the screws out counterclockwise evenly until you reach the correct idle speed per the manufacturer
9. Recheck the idle speed and compare it to the recommended manufacturer speed. If adjustment is required, you can now use the idle speed stop screw.

So, I'm an idiot, and for the past few days I have been adjusting the screws with the boat running, in neutral (not in drive) and with the throttle cable connected. Can it be done this way or is it useless?

If it's useless, and I'm able to get the throttle lever off (any help on how), what "lever into forward" do I move (#7)? The one that was connected to the throttle cable? How far forward? Wouldn't moving this forward do the same thing as leaving the throttle cable on and putting it into drive at the helm?

I'll have more questions once these ones are answered I'm sure. But since there are so many now, I'll leave it for you guys.

​THANKS!!!!!!!

 

[jimmbo]

"7. With the engine running and throttle lever disconnected, move the lever into forward and turn the mixture screws clockwise slowly until the engine speed JUST begins to drop. Jot down the number of turns.
8. Now back the screws out counterclockwise evenly until you reach the correct idle speed per the manufacturer"

I have never heard of setting a carb in that manner, except on an emission carb on a car

Normally I would
1) back the idle mix screws out 1 1/2 turns from lightly seated.
2) start engine and run till warm, making sure choke is fully open

I myself like to use a vacuum gauge. I just used a tee added to the choke pull off hose
Without a vacuum gauge, a good low RPM tach and adjust for highest idle

3) In gear, at a slightly faster than normal idle, adjust each side for highest vacuum. If engine speeds up, reduce rpm and continue adjusting.
4) set idle speed in gear to spec.
5) going back to the mix screws again adjust to see if vacuum increases.
6) as the carb as an accelerator pump, there should be no need to set the idle mix any richer than best idle.

 

[Surfnsnowboard3]

"7. With the engine running and throttle lever disconnected, move the lever into forward and turn the mixture screws clockwise slowly until the engine speed JUST begins to drop. Jot down the number of turns.
8. Now back the screws out counterclockwise evenly until you reach the correct idle speed per the manufacturer"

I have never heard of setting a carb in that manner, except on an emission carb on a car

Normally I would
1) back the idle mix screws out 1 1/2 turns from lightly seated.
2) start engine and run till warm, making sure choke is fully open

I myself like to use a vacuum gauge. I just used a tee added to the choke pull off hose
Without a vacuum gauge, a good low RPM tach and adjust for highest idle

3) In gear, at a slightly faster than normal idle, adjust each side for highest vacuum. If engine speeds up, reduce rpm and continue adjusting.
4) set idle speed in gear to spec.
5) going back to the mix screws again adjust to see if vacuum increases.
6) as the carb as an accelerator pump, there should be no need to set the idle mix any richer than best idle.

Thanks for taking the time to respond.

Reference your #3, in gear. Again, bear in mind I am new to this please...does in gear mean I push the throttle down slightly at the helm (I'm running on muffs, so the prop will naturally start spinning right?)? If not, what EXACTLY does in gear mean? I thought "idle" meant at neutral, how are you at idle while in gear?

 

[Surfnsnowboard3]

Page 57 is the OEM instructions for the idle mixture...http://boatinfo.no/lib/omc/manuals/1986-1998omcmanual.html#/56

 

[jimmbo]

Interesting read. Extremely poorly written, it doesn't even reference where the mixture screws are on a Holley, it shows a pic of a one barrel carb
A great example of why aftermarket books are not the best choice for repairing marine engines

When I say in gear. I mean in the water, either tied to a very solid dock, anchoured securely by the stern, or somebody else at the helm, and shifted into forward. In a boat, the idle speed is the lowest recommended rpm while in gear with a warm engine. Disconnecting the throttle linkage at the carb is a way to ensure you have control of the engine speed. Once the final idle speed is set, in gear and under load, the linkage may need to be adjusted to provide the proper preload to ensure throttle is closed

 

[Surfnsnowboard3]

Thank you for the response. Things are getting much clearer for me.

This is where I'm confused now:

If I start off with the idle speed screw "just seated, but not pushing on the idle cam" and then make the mixture screw adjustments to the highest RPM (say 2200 for sake of argument, no clue if that's it). Ok, so now the idle mixture screws are set. But I can't back off the idle speed screw anymore to get the RPM down from 2200 to 550. The idle speed screw is backed out already. Doesn't turning it IN make the idle go even higher?

Thanks and happy 4th. 'Merica!!!!

 

[jimmbo]

IGNORE that book. It is full of Errors and Typos, at least in that section. Idle speed is not set against an 'idle cam'. It would be set against a stop. Fast idle for cold engine with choking would be done against a cam. The Holley 2300 is an extremely simple straightforward carb to work with.

 

[Surfnsnowboard3]

I DID IT. It was so easy after I stopped psyching myself out and second guessing myself. PLUS, removing the throttle cable was easy (cotter pin) and as soon as I did that, the rest was simple. Now I did this all on muffs. I'll be taking the boat out to the lake tomorrow. Do you guys expect my needing to adjust the mixture in or out once I'm on the water?

Thanks

 

[HT32BSX115]

I DID IT. It was so easy after I stopped psyching myself out and second guessing myself. PLUS, removing the throttle cable was easy (cotter pin) and as soon as I did that, the rest was simple. Now I did this all on muffs. I'll be taking the boat out to the lake tomorrow. Do you guys expect my needing to adjust the mixture in or out once I'm on the water?

Thanks

You may need to increase the idle a bit when in gear........engaging the drive at too low an RPM might stall the engine.

 

[jimmbo]

I DID IT. It was so easy after I stopped psyching myself out and second guessing myself. PLUS, removing the throttle cable was easy (cotter pin) and as soon as I did that, the rest was simple. Now I did this all on muffs. I'll be taking the boat out to the lake tomorrow. Do you guys expect my needing to adjust the mixture in or out once I'm on the water?

Thanks

Yep. It will probably need richening and as mentioned before an increase in idle speed. Both to be done in gear

 

[Surfnsnowboard3]

Remind me...does screwing in or out richen the mix?

 

[jimmbo]

Marine Holleys follow the standard clockwise(in) to lean, counter clockwise(out) to richen. I am assuming your carb is a marine carb.

 

[Surfnsnowboard3]

Yes it is. Thanks

 

[Surfnsnowboard3]

Just got back from the lake. As expected, when on the water under load, the idle dropped. About a quarter turn out on each side and some adjustment on the idle screw, and ran like a dream.

Thanks for all the help everybody. I'm excited to have fixed all these issues myself, thanks to your help.