Return to the home page...

Go Back   Moyer Marine Atomic 4 Community - Home of the Afourians > Discussion Topics > Fuel System

Reply
 
Thread Tools Display Modes
  #1   IP: 99.7.118.97
Old 12-12-2018, 04:14 PM
bcbristoll bcbristoll is offline
Senior Member
 
Join Date: Apr 2018
Location: St. Francis, Wis.
Posts: 18
Thanks: 0
Thanked 0 Times in 0 Posts
Motor runs fine but stalls at high rpm

I'm having trouble witlh my idle speed. The engine starts easily and runs fine...that is until I Throttle down. When I do, the engine just stalls at pretty high rpm. there is no studder...no nothing it just stalls. Any ideas ?? I'm planning on pulling the carb in the spring and rebuilding but just can't understand why it just cuts out.
Reply With Quote
  #2   IP: 138.207.175.58
Old 12-12-2018, 04:37 PM
Administrator's Avatar
Administrator Administrator is offline
MMI Webmaster
 
Join Date: Oct 2004
Location: Chestertown, MD (Langford Creek)
Posts: 2,198
Thanks: 1,335
Thanked 365 Times in 182 Posts
Electric fuel pump?

Bill
Reply With Quote
  #3   IP: 100.36.65.17
Old 12-13-2018, 09:30 AM
edwardc's Avatar
edwardc edwardc is offline
Afourian MVP
 
Join Date: Aug 2009
Location: Laurel, MD
Posts: 2,509
Thanks: 153
Thanked 595 Times in 388 Posts
I can think of two possibilities:
  1. Clogged or dirty Idle Jet
  2. Stuck centrifugal advance weights
__________________
@(^.^)@ Ed
1977 Pearson P-323 "Dolce Vita"
with rebuilt Atomic-4

Reply With Quote
  #4   IP: 137.200.32.54
Old 12-13-2018, 09:50 AM
joe_db's Avatar
joe_db joe_db is offline
Afourian MVP
 
Join Date: May 2009
Posts: 4,474
Thanks: 49
Thanked 1,026 Times in 721 Posts
I am voting for clogged idle jet myself, but it is always worth checking the fuel pressure IMHO. Not sure about stuck weights, if stuck retarded the idle would be fine and I think stuck advanced would cause rough idle, not sudden cutoff. Very easy to check though.
Reply With Quote
  #5   IP: 97.93.70.7
Old 12-13-2018, 11:22 AM
Dave Neptune Dave Neptune is offline
Afourian MVP, Professor Emeritus
 
Join Date: Jan 2007
Location: Grove, Oklahoma
Posts: 5,035
Thanks: 711
Thanked 1,289 Times in 839 Posts
I'll go with a plugged jet or a vacuum leak. Check for the leak before removing the carb.

Common vac leaks are the scavenge tube, the carb base and manifold carb base gasket(s) if equipped with a PCV valve which can be easily plugged for checking.

Dave Neptune
Reply With Quote
  #6   IP: 50.35.34.141
Old 12-14-2018, 09:51 AM
capnward's Avatar
capnward capnward is offline
Afourian MVP
 
Join Date: Aug 2012
Location: Deer Harbor WA
Posts: 335
Thanks: 41
Thanked 147 Times in 107 Posts
I had that problem, and it was a piece of crud in the idle jet. I removed the jet and held it up to the light. I could see the obstruction. Cleaned it out with a thin wire from a wire brush. Now I remove and clean the carb and inspect the idle jet every spring. That procedure should be something we A4 owners are comfortable with.
Reply With Quote
  #7   IP: 72.194.222.152
Old 12-14-2018, 03:36 PM
JOHN COOKSON JOHN COOKSON is offline
Afourian MVP, Professor Emeritus
 
Join Date: Nov 2008
Posts: 3,500
Thanks: 54
Thanked 855 Times in 629 Posts
Lots of good ideas have been posted.

Have you tried simply adjusting the idle mixture? Or maybe the idle speed adjustment has slipped.

Turn the idle mixture adjustment screw in till it seats then back it out 1 1/2 turns. If this gives you any an idle you can further adjust from this setting.
If you can't get satisfactory idle by adjusting the mixture and or idle RPM adjustment you will need to clean the carb or look further for the problem.

TRUE GRIT
Reply With Quote
  #8   IP: 24.152.132.140
Old 12-14-2018, 03:53 PM
ndutton's Avatar
ndutton ndutton is offline
Afourian MVP
 
Join Date: May 2009
Location: Torrance, CA
Posts: 9,619
Thanks: 198
Thanked 2,208 Times in 1,425 Posts
Timing

In addition to the excellent carburetion/mixture suggestions, proper timing makes a huge improvement on idle behavior.
__________________
Neil
1977 Catalina 30
San Pedro, California
prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few others
Reply With Quote
  #9   IP: 96.238.21.148
Old 12-16-2018, 10:36 AM
ED.D's Avatar
ED.D ED.D is offline
Senior Member
 
Join Date: Oct 2017
Location: Warwick, Rhode Island
Posts: 12
Thanks: 16
Thanked 3 Times in 3 Posts
I will 2nd idle jet adjustment easy to try and it has fixed the same issue with me a number of times
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Issues while cruising: High Temp, High Oil Pressure, White Smoke Tkenopic Troubleshooting 14 07-23-2017 11:31 AM
Atomic Four puzzler: Stalls out after 60 seconds gary randall Troubleshooting 13 07-22-2013 10:06 PM
Engine stalls at idle once warm dleedvm Troubleshooting 16 04-24-2012 08:29 AM
Momentary high rev's Crash Drive Train / Propellers 9 10-10-2011 10:10 PM
carburetor Problems - HIGH RPMs jakecolumbia8.3 Fuel System 10 10-10-2011 08:58 PM


All times are GMT -4. The time now is 06:52 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2024, vBulletin Solutions, Inc.


Universal® is a registered trademark of Westerbeke Corporation

Copyright © 2004-2024 Moyer Marine Inc.

All Rights Reserved