Idles high, not low, dies out. Different circumstances/situation.

[crbedd]

Greetings, Hi! I know the idles high, but not low, dies out issue has been posted before but circumstances/situation and what’s done and what to do 1, 2, 3 etc. can be different.

In this case/situation, the carb was recently rebuilt along with replacing the marine fuel filter water separator.

Then just a couple of weeks ago, the boat ran out of gas so it has a fresh tank of gas. But maybe the dregs from the bottom of the gas tank might have been drawn out up into engine. If so, would that mean first replacing the fuel filter even though it was recently replaced?

A boat mechanic suggested adjusting the carburetor that could include varying the idle speed and adjusting the idle mixture. If so, are they done separately or together. If separate, what is done first?

In this case/situation, what would you suggest/recommend for an engine that runs well when the idle is high, but then struggles and dies when it’s low.

Thanks!! Randy

[JOHN COOKSON]

A boat mechanic suggested adjusting the carburetor that could include varying the idle speed and adjusting the idle mixture. If so, are they done separately or together. If separate, what is done first?
Thanks!! Randy

Try what the mechanic suggested. Turn the mixture adjustment to the seat then back it out 1 1/2 turns. Then try adjusting the the idle speed and idle mixture, balancing the two against each other as you adjust them to to find an idle that is proper for your engine. Each engine is a bit different. You will need to find the adjustments that your engine likes.
If this procedure does not result in a idle you are happy with put up a post and we will go to the next step(s).
Is the choke opening and closing the way it should? What do the spark plugs look like? Any sign of rich running?

ex TRUE GRIT

[ndutton]

Consider what is different at higher RPM rather than normal idle. The carburetor meters fuel through a different circuit at higher RPM so attention in that area is in order. However, there's something else. The timing is significantly advanced too because of the centrifugal advance system inside the distributor. It wouldn't do any harm to be certain the timing is set properly and the advance weights move freely.

[crbedd]

Idles high, not low, dies out. Different circumstances/situation.

John, Thank you for the reply, your interest and excellent suggestions and questions. And the offer to post if the idling adjusting is not working out.

Please bear with me that I am new at learning all about the Atomic 4 Engine, but serious. I have learned the hard way from this idle issue that Ken at Moyer Marine is right about doing that—daily. So I have started gathering together a number of Atomic 4 manuals, aids, tools and resources.

+++++++++++++++++++++++++++++++++++++++++++

First your questions.

1 I don’t know what the choke opening and closing should be, but the lever is pulling in and out okay and the choke seems to be doing its job.

2 The spark plugs are fine. They were just changed and gapped.

3 I don’t know what rich running is, means and the signs of it

+++++++++++++++++++++++++++++++++++++++++++

Just some clarifying. When I told the boat mechanic about the idle issue, he only said to adjust the carburetor, nothing more about what that meant, what to do. So along with the Atomic 4 Engine info gathering above, I also started finding out about adjusting the carb and first came across varying the idle speed and adjusting the idle mixture that I had mentioned.

But I should have asked and now asking WHAT ELSE DOES ADJUSTING THE CARB INVOLVE OR IS THAT IT?

+++++++++++++++++++++++++++++++++++++++++++

Idle Speed Adjustment https://www.moyermarineforum.com/for...ead.php?t=6691
that you contributed to has been the most helpful post, article so far in learning and understanding carb, idle adjusting and to try what you suggested

Turn the mixture adjustment to the seat then back it out 1 1/2 turns. Then try adjusting the idle speed and idle mixture, balancing the two against each other

I am editing this post after posting. I realized I may have gotten the turning backwards.

1 Is the engine on or off when adjusting the idle, carb?

2 Am I turning the idle mixture adjustment screw CLOCKWISE?

3 Does to the seat mean to the end that I can’t turn, tighten it anymore?

4 Then am I turning, unscrewing the screw COUNTERCLOCKWISE 1 1/2 turns?

5 Then am I turning the idle speed adjustment screw clockwise or counterclockwise?

6 How many turns am I turning it?

7 What does it mean to balance the two against each other?

How do you avoid the misunderstandings and trouble you can get into that I Like Rust, Bill T was pointing out in the post above?

8 Other. Anything I am missing, didn’t ask, should know before trying out what you are suggesting and adjuting the idle, carb?

Thanks, Best,

Randy

[crbedd]

Idles high, not low, dies out. Different circumstances/situation.

Neil, Thanks for your post that someone else, Sam also liked and appreciated. Yes, the timing is definitely something to check and be part of the basic maintenance I would like to have.

As mentioned in the reply to John above, I am brand new to learning all about Atomic 4 Engines and how to maintain and service them.

So I don’t know yet what it means or what to do to make sure that “the timing is set properly and the advance weights move freely”.

I am wondering if you could direct me to any info, articles, posts that you suggest/recommend, that would teach, explain things well? Then I am not just randomly searching the topic not knowing what I am getting and if it is any good or not.

Thanks, Randy

[JOHN COOKSON]

John, Thank you for the reply, your interest and excellent suggestions and questions. And the offer to post if the idling adjusting is not working out.
1 I don’t know what the choke opening and closing should be, but the lever is pulling in and out okay and the choke seems to be doing its job.
2 I don’t know what rich running is, means and the signs of it
3 Is the engine on or off when adjusting the idle, carb?
4 Am I turning the idle mixture adjustment screw CLOCKWISE?
4 Does to the seat mean to the end that I can’t turn, tighten it anymore?
4 Then am I turning, unscrewing the screw COUNTERCLOCKWISE 1 1/2 turns?
Randy

1 The choke butterfly should horizontal when the cockpit knob is pushed down ie fully open. You will need to take the back flame arrestor off to observe this.
2 The carburetor mixes air and fuel and (if properly operating) supplies the mixture in the to the engine at the proper ratio for optimal performance at various RPMs. To rich means there is to much fuel in the mixture for optimal engine performance. Soot like deposits on the spark plugs can be a sign of rich running ie not enough air to burn the fuel completely.
3 Make the adjustments with the engine running, warmed up, with the choke fully open. When the engine is cold you should be able to get a decent idle with partial choke. This is normal.
4 The confusion probably came about because the idle needle adjustment is changing the amount of air that is being let into the idle system not the amount of gas. As starting point lightly seat the idle needle then back it out 1 1/2 turns.

Hope this helps.

ex TRUE GRIT

[Sam]

Unless I missed it in the write you should order the Moyer service manual for about $50. Just about every question you have can be answered in easy to understand language. My other suggestion is to binge watch some of the the Youtube videos - carburator, timing, coil etc. Afterwards you will be able to deal with most issues and also appreciate the responses as well.

[crbedd]

Idles high, not low, dies out. AND ATOMIC 4 RESOURCES for the community.

John and Sam, Thank you!

Sam, You are right about needing to do some heavy-duty reading and video watching in order to better understand responses, postings made like John's last one. I am most ThankFull, name of my boat and appreciative of you, John, Neil, others that give so much tirelessly, faithfully.

So I had gathered together a number of different Atomic 4 resources that I am sharing below for hopefully the benefit of the Forum, Community. That they might not only help those like me that are struggling to learn and engine, tech-challenged, impaired but maybe it might help pros like you, John and Neil help those new, learning or like me.

ATOMIC 4 ENGINES

Universal Atomic Four Marine Engine Maintenance Facebook

https://www.facebook.com/groups/208227399713304/

Atomic 4 Marine Engine Service and Repair Manual

https://www.fdlaudubon.org/page19/assets/A4RepairMaint.pdf

ATOMIC 4 OPERATION AND MAINTENANCE MANUAL

https://www.westerbeke.com/operator's%20manual/200156_atomic4_operator_man.pdf

https://www.manualslib.com/manual/615712/Westerbeke-Atomic-4.html

Universal Atomic 4 & Stevedore

https://everythingaboutboats.org/atomic-4/

Atomic 4 Owners Manual

https://l-36.com/read_html.php?file=Atomic4/atomic4&title=Atomic_4_Owners_Manual

Atomic 4 Care

https://www.youtube.com/watch?v=wRsVCuzyo2s

Atomic 4 Engine: Smooth, worth another look

https://goodoldboat.com/atomic-4/

Checking the Basics of the Atomic 4 Engine

http://www.cncphotoalbum.com/atomic4/basics/atomic4.htm

https://www.cruisersforum.com/forums/f54/atomic-4-a-2464.html

Moyer Marine Videos

https://moyermarine.com/video_tech-tips/

Trouble shooting full version

https://www.moyermarineforum.com/forums/archive/index.php/f-2.html

Understanding the Atomic 4 Oil System

https://moyermarine.com/nl12-1-17/

[JOHN COOKSON]

You're one of us now. Welcome aboard.

ex TRUE GRIT

[crbedd]

One of us now

John, Thank You!