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: 158.222.232.90
Old 06-25-2016, 07:37 AM
niar98 niar98 is offline
Member
 
Join Date: Sep 2014
Posts: 2
Thanks: 5
Thanked 0 Times in 0 Posts
Engine only runs choke out

Hi

New the world of atomic 4 engines. My problem is I can start the engine with the choke fully out and throttle a bit above idle. Engine will run rough. Any attempt to move choke or throttle causes the engine to stall. I tried to let it run for a while till it reached operating temperature and then tried to move the throttle or choke and again stall.

Based on the reading this blog I am guessing the fuel pump is the issue. A electric fuel pump presently installed.

Would appreciate any tips and insights.

Thanks.
Reply With Quote
  #2   IP: 207.118.20.35
Old 06-25-2016, 02:46 PM
capnward's Avatar
capnward capnward is online now
Afourian MVP
 
Join Date: Aug 2012
Location: Deer Harbor WA
Posts: 307
Thanks: 30
Thanked 126 Times in 97 Posts
Welcome to this forum. These guys have been a big help to me understanding my trusty A-4 engine.
If your engine will start, you are not far away from it running right. I doubt your fuel pump is the issue. It could be a number of things. It could be the coil, the distributor, or timing, but my experience has been that the usual cause of symptoms like yours is junk in the fuel, lodging in the various tiny passages in the carburetor, particularly the idle jet or main jet. It may be there is stuff in your fuel tank, and the filters are clogged and passing the stuff into the carb. I personally believe that using non-ethanol fuel and keeping the tank close to full helps keep the bad stuff in the tank and out of the carb.
If you replace the filters, and clean out and reassemble your carb, I'm betting you will fix it, at least for a while. The others on this forum will go into more detail. Make sure you have a Moyer manual. A fuel pressure gauge just before the carburetor can tell you if you are getting enough gas. If you run long enough with the choke closed, the plugs will foul.
Good Luck!
Reply With Quote
The Following User Says Thank You to capnward For This Useful Post:
niar98 (06-27-2016)
  #3   IP: 184.0.19.114
Old 06-25-2016, 06:13 PM
roadnsky's Avatar
roadnsky roadnsky is offline
Afourian MVP
 
Join Date: Dec 2008
Location: Lake Mead, NV
Posts: 3,095
Thanks: 24
Thanked 445 Times in 300 Posts
Welcome to the forum!
As CAPNWARD suggested, get the MMI Bible. It's a must.

I doubt the issue is your fuel pump.
Is the pump a Manual or Electric?

Another question...
Have you looked at your plugs? How do they look?

Having to run the engine using full choke suggests a lean mixture.
A quick and easy test would be to try turning the idle mixture screw a ¼ turn IN.
(Clockwise)
See if it makes any difference. If no difference or just a little better, then try another ¼ turn IN.
Continue this exercise until you get a smooth idle.

Remember that the idle adjustment (on top of the carburetor with a screw driver slot) adjusts the air portion of the mixture,
so turning the adjustment IN makes the mixture richer, and backing it OUT makes it leaner.

If adjusting the idle doesn't work, we'll go deeper. One step at a time...
Attached Images
 
__________________
-Jerry

'Lone Ranger'

1978 RANGER 30
Reply With Quote
The Following 2 Users Say Thank You to roadnsky For This Useful Post:
Administrator (06-25-2016), niar98 (06-27-2016)
  #4   IP: 68.108.255.88
Old 06-26-2016, 02:12 AM
JOHN COOKSON JOHN COOKSON is offline
Afourian MVP, Professor Emeritus
 
Join Date: Nov 2008
Posts: 3,500
Thanks: 54
Thanked 852 Times in 626 Posts
98
Another welcome to the forum.
A fuel pressure gauge between the fuel pump and the carburetor would sort this issue out real quick.

TRUE GRIT

Last edited by JOHN COOKSON; 06-26-2016 at 02:25 AM.
Reply With Quote
The Following User Says Thank You to JOHN COOKSON For This Useful Post:
niar98 (06-27-2016)
  #5   IP: 32.211.28.40
Old 06-26-2016, 07:09 PM
Al Schober's Avatar
Al Schober Al Schober is offline
Afourian MVP
 
Join Date: Jul 2009
Location: Uncasville, CT
Posts: 1,900
Thanks: 12
Thanked 490 Times in 355 Posts
Niar,
Your symptoms are classic for a partially clogged main jet. This can often be cleared by shutting off the fuel, removing the plug over the main jet, and running a fine needle or piece of wire through the jet. Some folks have an adjustable main jet, and clear these clogs (sometimes) by running the needle in and out.
You're going to spill fuel, so smoking lamp is out. I like to jam small towels in the area under the carb to catch the fuel, then hang them on the lifeline to dry.
Keep in mind that all fuel flow is towards the carb, so guess where all the krap ends up? Personally, I try to keep my tank clean, have a big filter before the electric fuel pump, then a small filter between the pump and the carb. I still get the occasional piece of krap that clogs the main jet or gets into the float valve and causes the carb to overflow. I go so far as to keep a second carb on board, cleaned and ready to go. I have good access and the change doesn't take long.
Reply With Quote
The Following User Says Thank You to Al Schober For This Useful Post:
niar98 (06-27-2016)
  #6   IP: 96.255.32.75
Old 06-27-2016, 08:56 PM
niar98 niar98 is offline
Member
 
Join Date: Sep 2014
Posts: 2
Thanks: 5
Thanked 0 Times in 0 Posts
Update

Thanks for all the helpful tips. I have ordered a pressure gauge. I am a working/family man so I won't be able to try any of the ideas you all gave me until this weekend. I will report back on my progress.
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
engine only runs with excessive choke gary gerber Troubleshooting 68 05-03-2019 12:01 PM
Only runs with full choke Bold Rascal Fuel System 10 11-08-2011 01:22 PM
Engine Sputters and Coughs, and Needed Choke to Run Smooth CaptainChas Troubleshooting 9 06-30-2009 10:50 PM
Engine needs to have choke on to run hobie61 Troubleshooting 2 06-18-2009 08:58 AM
engine runs rough then dies after 20min run time ray mizell Electrical 9 08-20-2008 05:47 PM


All times are GMT -4. The time now is 05:11 PM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2022, vBulletin Solutions, Inc.


Universal® is a registered trademark of Westerbeke Corporation

Copyright © 2004-2022 Moyer Marine Inc.

All Rights Reserved