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: 208.186.29.114
Old 07-01-2016, 01:16 AM
seattlesailor seattlesailor is offline
Senior Member
 
Join Date: May 2016
Location: Seatle
Posts: 12
Thanks: 5
Thanked 0 Times in 0 Posts
Smile motor runs for one minute and then stops

Just did a fuel pump replacement last weekend with Don's kit. Replaced pump, hoses, oil pressure switch. The motor started right away after we finished the work an we ran it for 20 minutes, then sailed and ran it again back to the marina.
Today my friend took the boat and said the motor started right away but stopped after one minute. He said he did not mater if he tried to run it at lower or higher rpm, it always stopped after one minute after every restart.
Could it be water or junk in the fuel tank?
Please let me know what you think.

Thanks Michel
Reply With Quote
  #2   IP: 68.108.255.88
Old 07-01-2016, 01:39 AM
JOHN COOKSON JOHN COOKSON is offline
Afourian MVP, Professor Emeritus
 
Join Date: Nov 2008
Posts: 3,500
Thanks: 54
Thanked 844 Times in 619 Posts
Welcome to the forum. You've come to the right place for all things A4 related.

You are running on one carburetor bowl of fuel. When that runs out the engine quits. It sounds like the OPSS is not working correctly - even though it is new. Bypass or short across the OPSS temporarily and see if the shut downs go away.If this does not cure the shut downs we'll go to the next step.

BTW what oil pressure are you running? Maybe you don't have enough oil pressure to close the OPSS.

TRUE GRIT
Reply With Quote
The Following User Says Thank You to JOHN COOKSON For This Useful Post:
Administrator (07-01-2016)
  #3   IP: 208.186.29.114
Old 07-01-2016, 08:04 PM
seattlesailor seattlesailor is offline
Senior Member
 
Join Date: May 2016
Location: Seatle
Posts: 12
Thanks: 5
Thanked 0 Times in 0 Posts
John,

Thank you for the quick response, I will try as you suggest to bypass the OPSS. I believe the oil oil pressure is usually around 35 psi.
So if I understand the OPSS is not a high pressure safety but a low pressure safety?

Thanks
Michel
Reply With Quote
  #4   IP: 32.211.28.40
Old 07-01-2016, 10:14 PM
Al Schober's Avatar
Al Schober Al Schober is offline
Afourian MVP
 
Join Date: Jul 2009
Location: Uncasville, CT
Posts: 1,863
Thanks: 12
Thanked 453 Times in 332 Posts
Michel,
Yes, the OPSS is a low pressure safety switch. It stops the electrical pump from pumping fuel if the engine stops - just like the mechanical pump. When I need to short my switch and force the electrical pump to run, I just use an adjustable wrench.
Many of us have added a pressure gauge to the carb inlet. You'll need a small gauge (10 or 15 psi, try eBay). Mine has a rear inlet and screws into one leg of a 1/8" NPT tee. The side of the tee has a nipple and goes to the carb inlet. The other leg of the tee has a hose barb for the line to the pump (via the secondary filter).
Reply With Quote
  #5   IP: 50.189.109.105
Old 07-01-2016, 10:36 PM
BunnyPlanet169's Avatar
BunnyPlanet169 BunnyPlanet169 is offline
Afourian MVP, Professor Emeritus
 
Join Date: May 2010
Location: York, ME
Posts: 952
Thanks: 25
Thanked 92 Times in 65 Posts
Given that it worked, and then stopped, I'd be curious to re-crimp/confirm the electrical terminations in the OPSS pump circuit as well.....
__________________
Jeff


S/V Bunny Planet
1971 Bristol 29 #169
Reply With Quote
  #6   IP: 68.108.255.88
Old 07-02-2016, 02:29 AM
JOHN COOKSON JOHN COOKSON is offline
Afourian MVP, Professor Emeritus
 
Join Date: Nov 2008
Posts: 3,500
Thanks: 54
Thanked 844 Times in 619 Posts
Any time you trouble shoot a electrical device it is important to test the device itself and the associated electrical circuit.

So:The next step if shorting across or bypassing the OPSS doesn't end the shut downs is to make sure you are getting 12 volts to the OPSS.

Pull the wire off the OPSS that brings power to the OPSS, turn the key or switch to the run position and see if you can read 12 volts at the end of this wire. Don't leave the key in the run position when the engine isn't running for more than a minute or two or the coil may be heat damaged.

TRUE GRIT
Reply With Quote
  #7   IP: 208.186.29.114
Old 07-05-2016, 01:13 AM
seattlesailor seattlesailor is offline
Senior Member
 
Join Date: May 2016
Location: Seatle
Posts: 12
Thanks: 5
Thanked 0 Times in 0 Posts
Thumbs up

I had a chance to go to the boat today. First thing I did was to check the 5 amps fuse and it was blown. Replaced the fuse and motor runs fine.
Any idea why the fuse will go out? By the way I installed the fuse with the new kit which did not exists with the previous Facet pump.

I bought a bunch of fuses for the next times this happens, Any idea how to prevent this to happen again?

Thanks Michel
Reply With Quote
  #8   IP: 107.0.6.242
Old 07-05-2016, 01:25 AM
hanleyclifford hanleyclifford is offline
 
Join Date: Mar 2010
Posts: 6,800
Thanks: 121
Thanked 179 Times in 151 Posts
Talking

If you are running both ignition and fuel pump thru a 5 amp fuse you are taxing that fuse. Ignition be from 1 to 4 amps, typically, and the pump may want 3 or 4 amps. I like to see ignition on an independent circuit for this and other reasons.
Reply With Quote
  #9   IP: 208.186.29.114
Old 07-05-2016, 02:11 AM
seattlesailor seattlesailor is offline
Senior Member
 
Join Date: May 2016
Location: Seatle
Posts: 12
Thanks: 5
Thanked 0 Times in 0 Posts
Make sense. Thanks. Curious to see what John Has to say about this. Does he have a 10 AMPS fuse? t I know from one his past posting that this is the set up he has.
Reply With Quote
  #10   IP: 50.189.109.105
Old 07-05-2016, 07:23 AM
BunnyPlanet169's Avatar
BunnyPlanet169 BunnyPlanet169 is offline
Afourian MVP, Professor Emeritus
 
Join Date: May 2010
Location: York, ME
Posts: 952
Thanks: 25
Thanked 92 Times in 65 Posts
Quote:
Originally Posted by hanleyclifford View Post
If you are running both ignition and fuel pump thru a 5 amp fuse you are taxing that fuse. Ignition be from 1 to 4 amps, typically, and the pump may want 3 or 4 amps. I like to see ignition on an independent circuit for this and other reasons.
Careful. For safety, it makes sense to only power the fuel pump when the ignition is on. For this reason, it's usually powered off coil+. This, plus the OPSS, prevents an energized pump except for when the engine is running.

If the fuse is between coil + and the fuel pump, it's only going to see the load in that branch circuit. It will not see the coil, or E.I., or alternator excite which are also usually powered from coil +.

IIRC the pump draws about 2A, and a 5A fuse comes standard with the MMI kit.

The MMI wiring diagram shows a 20A fuse and a 12AWG wire from the ignition terminal on the starting switch and coil+. Your install may be different, but the 5A fuse in the fuel pump branch circuit is appropriate for these conditions.

http://www.moyermarine.com/forums/sh...ring+schematic
__________________
Jeff


S/V Bunny Planet
1971 Bristol 29 #169
Reply With Quote
The Following User Says Thank You to BunnyPlanet169 For This Useful Post:
ndutton (07-05-2016)
  #11   IP: 24.152.132.65
Old 07-05-2016, 09:46 AM
ndutton's Avatar
ndutton ndutton is offline
Afourian MVP
 
Join Date: May 2009
Location: Torrance, CA
Posts: 9,332
Thanks: 182
Thanked 1,837 Times in 1,229 Posts
Seattle, please confirm the fuse location in the circuit, i.e., protecting the pump only. Without that information the advice is going in a couple of different directions.

If the fuse is protecting the pump only and it ran fine the first day and not the second, carefully follow your wiring and look for damage. Laying across a sharp edge or a hot exhaust pipe is all it takes.

FYI, the published Facet pump current specification is 1.6 amps.
__________________
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
  #12   IP: 107.0.6.150
Old 07-05-2016, 10:52 AM
hanleyclifford hanleyclifford is offline
 
Join Date: Mar 2010
Posts: 6,800
Thanks: 121
Thanked 179 Times in 151 Posts
Quote:
Originally Posted by BunnyPlanet169 View Post
Careful. For safety, it makes sense to only power the fuel pump when the ignition is on. For this reason, it's usually powered off coil+. This, plus the OPSS, prevents an energized pump except for when the engine is running.

If the fuse is between coil + and the fuel pump, it's only going to see the load in that branch circuit. It will not see the coil, or E.I., or alternator excite which are also usually powered from coil +.

IIRC the pump draws about 2A, and a 5A fuse comes standard with the MMI kit.

The MMI wiring diagram shows a 20A fuse and a 12AWG wire from the ignition terminal on the starting switch and coil+. Your install may be different, but the 5A fuse in the fuel pump branch circuit is appropriate for these conditions.

http://www.moyermarine.com/forums/sh...ring+schematic
Careful is as careful does. The fuel pump should have it's own OPSS. In fact I have three on my boat - the third activates the alternator.
Reply With Quote
  #13   IP: 107.0.6.150
Old 07-05-2016, 10:59 AM
hanleyclifford hanleyclifford is offline
 
Join Date: Mar 2010
Posts: 6,800
Thanks: 121
Thanked 179 Times in 151 Posts
Talking

Quote:
Originally Posted by seattlesailor View Post
Make sense. Thanks. Curious to see what John Has to say about this. Does he have a 10 AMPS fuse? t I know from one his past posting that this is the set up he has.
Clearly the 5 amp fuse is not adequate for your installation. To repeat, IMO mixing ignition, pump, alternator on the same circuit is sloppy engineering.
Reply With Quote
  #14   IP: 50.206.207.10
Old 07-05-2016, 11:18 AM
BunnyPlanet169's Avatar
BunnyPlanet169 BunnyPlanet169 is offline
Afourian MVP, Professor Emeritus
 
Join Date: May 2010
Location: York, ME
Posts: 952
Thanks: 25
Thanked 92 Times in 65 Posts
Respectfully, I disagree. IMO, it is perfectly good engineering in having a large, protected wire to coil +, and then short branch circuits from there.

There are a several loads in close physical proximity to coil + that are only normally energized from IGN on the starter key switch. Coil, E.I., fuel pump, alternator excite.

I actually installed a small terminal block next to my coil yesterday for exactly this reason. Too many terminals to hang off the coil+ !
__________________
Jeff


S/V Bunny Planet
1971 Bristol 29 #169
Reply With Quote
  #15   IP: 161.213.49.150
Old 07-05-2016, 12:19 PM
JOHN COOKSON JOHN COOKSON is offline
Afourian MVP, Professor Emeritus
 
Join Date: Nov 2008
Posts: 3,500
Thanks: 54
Thanked 844 Times in 619 Posts
something is probably grounded
Quote:
Originally Posted by ndutton View Post
Seattle, please confirm the fuse location in the circuit, i.e., protecting the pump only. Without that information the advice is going in a couple of different directions.
If the fuse is protecting the pump only and it ran fine the first day and not the second, carefully follow your wiring and look for damage. Laying across a sharp edge or a hot exhaust pipe is all it takes.
FYI, the published Facet pump current specification is 1.6 amps.
The instructions that came with my new, recently installed Facet fuel pump specified a 3 to 5 amp "automotive type" fuse. If the fuel pump is blowing a 10amp fuse something is the matter. Agree with Neil - something is grounded that shouldn't be grounded. Did you check the fuel pump lead to ground? Maybe the fuel pump has a short of some kind in it.
IMO each major circuit or device should be individually fuse protected.

TRUE GRIT
Reply With Quote
  #16   IP: 208.186.29.114
Old 07-05-2016, 12:29 PM
seattlesailor seattlesailor is offline
Senior Member
 
Join Date: May 2016
Location: Seatle
Posts: 12
Thanks: 5
Thanked 0 Times in 0 Posts
Fuse is off the coil like on Moyer's marine wiring schematic. The only difference with the schematic is that the existing wiring we replaced had a two prong connector at the OPSS, one going to the starter and one going to the pump. Once the fuse was blown we could still run the motor for a minute with the starter as mentioned in my initial post.
Reply With Quote
  #17   IP: 208.186.29.114
Old 07-05-2016, 12:31 PM
seattlesailor seattlesailor is offline
Senior Member
 
Join Date: May 2016
Location: Seatle
Posts: 12
Thanks: 5
Thanked 0 Times in 0 Posts
The fuse I installed is the 5 amps fuse from the kit not 10 amps.
Reply With Quote
  #18   IP: 50.206.207.10
Old 07-05-2016, 12:57 PM
BunnyPlanet169's Avatar
BunnyPlanet169 BunnyPlanet169 is offline
Afourian MVP, Professor Emeritus
 
Join Date: May 2010
Location: York, ME
Posts: 952
Thanks: 25
Thanked 92 Times in 65 Posts
Quote:
Originally Posted by seattlesailor View Post
The only difference with the schematic is that the existing wiring we replaced had a two prong connector at the OPSS, one going to the starter and one going to the pump.
Hmmm. 'Going to the starter'? I don't understand this.

The fuel pump circuit should only be Coil + --> Fuse --> OPSS --> Fuel Pump.

It there is another power take off from the OPSS AFTER the fuse, that's what's suspect.
__________________
Jeff


S/V Bunny Planet
1971 Bristol 29 #169
Reply With Quote
  #19   IP: 107.0.6.150
Old 07-05-2016, 01:14 PM
hanleyclifford hanleyclifford is offline
 
Join Date: Mar 2010
Posts: 6,800
Thanks: 121
Thanked 179 Times in 151 Posts
Talking

Quote:
Originally Posted by BunnyPlanet169 View Post
Respectfully, I disagree. IMO, it is perfectly good engineering in having a large, protected wire to coil +, and then short branch circuits from there.

There are a several loads in close physical proximity to coil + that are only normally energized from IGN on the starter key switch. Coil, E.I., fuel pump, alternator excite.

I actually installed a small terminal block next to my coil yesterday for exactly this reason. Too many terminals to hang off the coil+ !
Undoubtedly you can get away with that but you should know the potential for voltage variations is greater than if you had separate circuits. The question then becomes: what is the problem with voltage variations at coil +?
Reply With Quote
  #20   IP: 161.213.49.150
Old 07-05-2016, 01:34 PM
JOHN COOKSON JOHN COOKSON is offline
Afourian MVP, Professor Emeritus
 
Join Date: Nov 2008
Posts: 3,500
Thanks: 54
Thanked 844 Times in 619 Posts
Quote:
Originally Posted by seattlesailor View Post
Fuse is off the coil like on Moyer's marine wiring schematic. The only difference with the schematic is that the existing wiring we replaced had a two prong connector at the OPSS, one going to the starter and one going to the pump. Once the fuse was blown we could still run the motor for a minute with the starter as mentioned in my initial post.
Bet I know what the problem is!
The wire going to the starter is worn and rubbing against the engine block somewhere. This is where the short to ground is. Let the wire loose at the starter solenoid and pull it around the engine and inspect it. I've been through this exact drill. Kept me guessing for awhile.
The wire from the starter that is co joined with the lead to the fuel pump bypasses the OPSS so the fuel pump operates while the engine is being cranked.

TRUE GRIT
Reply With Quote
  #21   IP: 50.206.207.10
Old 07-05-2016, 01:43 PM
BunnyPlanet169's Avatar
BunnyPlanet169 BunnyPlanet169 is offline
Afourian MVP, Professor Emeritus
 
Join Date: May 2010
Location: York, ME
Posts: 952
Thanks: 25
Thanked 92 Times in 65 Posts
Quote:
Originally Posted by JOHN COOKSON View Post
The wire from the starter that is co joined with the lead to the fuel pump bypasses the OPSS so the fuel pump operates while the engine is being cranked. TRUE GRIT
Ahhh! I get it, thanks. I bet you're correct.

Is this really necessary? I would have thought there was enough fuel in the carb bowl to start, and oil pressure builds quickly while cranking anyway....
__________________
Jeff


S/V Bunny Planet
1971 Bristol 29 #169
Reply With Quote
  #22   IP: 161.213.49.150
Old 07-05-2016, 02:24 PM
JOHN COOKSON JOHN COOKSON is offline
Afourian MVP, Professor Emeritus
 
Join Date: Nov 2008
Posts: 3,500
Thanks: 54
Thanked 844 Times in 619 Posts
Quote:
Originally Posted by BunnyPlanet169 View Post
.
Is this really necessary? I would have thought there was enough fuel in the carb bowl to start, and oil pressure builds quickly while cranking anyway....
No, the bypass wire to the fuel pump wire from the starter is probably not necessary for the reason you mentioned.
This wire is shown in the wiring diagram for a late model engine with an electric fuel pump so it was a standard feature back then. I don't have a scan of the wiring diagram on this computer so I can't post it. I have the original A4 owner's manual so I know it's there. Perhaps there is a scan of it in the Drawings and Schematic section.

TRUE GRIT
Reply With Quote
  #23   IP: 107.0.6.242
Old 07-05-2016, 03:42 PM
hanleyclifford hanleyclifford is offline
 
Join Date: Mar 2010
Posts: 6,800
Thanks: 121
Thanked 179 Times in 151 Posts
Talking

Quote:
Originally Posted by BunnyPlanet169 View Post
Ahhh! I get it, thanks. I bet you're correct.

Is this really necessary? I would have thought there was enough fuel in the carb bowl to start, and oil pressure builds quickly while cranking anyway....
In 25 years of running these engines up and down the coast I have had only one instance where the normal cranking was not able to develop enough oil pressure to engage the OPSS (s) for ignition and electric fuel pump. This occurred after 10 hours of hard running north on the Chesapeake, head wind just as I entered the basin at Chesapeake city. I coasted to the anchorage and the engine started after ten minutes. I do not recommend putting the fuel pump on the "R" terminal for the same reason I recommend keeping the sea valve closed until the engine is running.
Reply With Quote
  #24   IP: 24.152.132.65
Old 07-05-2016, 05:32 PM
ndutton's Avatar
ndutton ndutton is offline
Afourian MVP
 
Join Date: May 2009
Location: Torrance, CA
Posts: 9,332
Thanks: 182
Thanked 1,837 Times in 1,229 Posts
Great, this again??

Quote:
Originally Posted by hanleyclifford View Post
Undoubtedly you can get away with that but you should know the potential for voltage variations is greater than if you had separate circuits. The question then becomes: what is the problem with voltage variations at coil +? . . . . . . IMO mixing ignition, pump, alternator on the same circuit is sloppy engineering.
A properly engineered circuit tolerates all connected loads regardless of their sum with no more than a 3% voltage drop. If you're experiencing more than 3% you need to re-read and understand the many posts on this forum describing voltage drop in detail, then rewire the substandard circuit according to established protocol. Alternatively, if you're unwilling to wire the circuit properly you can certainly add more and more circuits. A properly sized single circuit is far less complicated than several circuits with several oil pressure switches and much easier to troubleshoot due to its simplicity.

Remember, 3% max voltage drop. Anything more is indeed sloppy, poor and substandard engineering/installation.

Quote:
Originally Posted by hanleyclifford View Post
Clearly the 5 amp fuse is not adequate for your installation.
Sure it is and the fuse is doing exactly what it's supposed to do. Moyer Marine has sized the fuse in their kit @5 amps for good reason. The best any of us can do is follow the instructions included in the kit.
__________________
Neil
1977 Catalina 30
San Pedro, California
prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few others

Last edited by ndutton; 07-05-2016 at 07:24 PM.
Reply With Quote
  #25   IP: 208.186.29.114
Old 07-06-2016, 12:20 AM
seattlesailor seattlesailor is offline
Senior Member
 
Join Date: May 2016
Location: Seatle
Posts: 12
Thanks: 5
Thanked 0 Times in 0 Posts
Thank you all for all your contribution. I grabbed the A4 electrical schematic from Jeff response above (http://www.moyermarine.com/forums/sh...ring+schematic) and have a good idea of what I will do next. All your input is extremely valuable.

Michel
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


All times are GMT -4. The time now is 05:32 AM.


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