| Author |
Message |
    
kevin stone
Senior Member
Username: kdstone
Post Number: 52
Registered: 01-2009
| | Posted on Monday, July 08, 2013 - 05:58 pm: | 
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Hey everyone, hope your summers has not been to rainy. Here's my question for anyone with a thought.
I have been dealing with air in the fuel stream of our p-60. After numerous pressure tests I start to wonder if it could be coming from the fuel pump. I have the facet low pressure pump sold by Moyer marine. Anyone have an opinion on whether one of those pumps could have an internal failure and put air into the fuel? I have pressurized fuel lines to 30 lbs and also pulled the pickup tube and pressurized it also. I am reasonably sure that I have no leaks on the suction side.
Thanks for any input.
Kevin |
Richard A. Day Jr.
Senior Member
Username: richardday
Post Number: 1067
Registered: 11-2003
| | Posted on Monday, July 08, 2013 - 08:58 pm: |
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Kevin when all else has failed I suggest one look for trash on top of the float valve. You need to inject air through a straw if you don't have a nozzle about 2" long by 1/8" dia. so you can blow any trash out the inlet above the valve. Regards, Dick |
Jim
Member
Username: jimct
Post Number: 13
Registered: 08-2007
| | Posted on Monday, July 08, 2013 - 09:43 pm: |
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The only area air can get into the fuel line is between the fuel tank & the pump. Whether the pump can introduce air into the line might be best answered by a call to Moyer or Facet. Am assuming... and hoping... you have not smelled any fuel in the bilge. If the carb float valve was leaking, since it is on the pressure side, you would have smelled fuel and seen it dripping from the carb intake. Engine wouldn't run well at idle either.
One other thought: Facet pumps have an internal check valve to prevent fuel from syphoning back into the tank. If that valve is faulty it might also cause the problem.
First thing I'd do is to double check & tighten all fuel line connections between the tank & the pump and see it that scratches the itch.
Cheers! |
kevin stone
Senior Member
Username: kdstone
Post Number: 53
Registered: 01-2009
| | Posted on Monday, July 08, 2013 - 10:17 pm: |
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Thx for tips guys. I have already covered all of those bases tho. Carb is squeaky clean with a new float valve no flooding no gas leaks. Only thing not done is try a new fuel pump. I emailed DonMoyer today to get his take. Have not heard back yet. Engine is actually running great. Even idle is fine now. I am just concerned with the air bubbles in fuel flow. I can see them because of a plastic inline filter I installed just before the carb so I could work through some idle issues that I was having |
kevin stone
Senior Member
Username: kdstone
Post Number: 54
Registered: 01-2009
| | Posted on Tuesday, July 09, 2013 - 04:24 pm: |
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The other thing I wonder about.
I have 1/4" rubber fuel line the ethonal resistant type. It essentially runs down hill from tank to filter then down to pump. Then up about 6" to carb. I do have some dips and dives to the fuel line. Could I be trapping air which is just hard to bleed out? |
Jim
Member
Username: jimct
Post Number: 14
Registered: 08-2007
| | Posted on Tuesday, July 09, 2013 - 04:57 pm: |
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Is there a vacuum breaker in the fuel line at the top of the tank? If so, that might very well be the villain. Also, just for funsies, check to see if the fuel tank vent is clear.
Cheers! |
kevin stone
Senior Member
Username: kdstone
Post Number: 55
Registered: 01-2009
| | Posted on Tuesday, July 09, 2013 - 06:58 pm: |
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No check valve and vent is good. Did another pressure test today. Still have found no leaks |
Jim
Member
Username: jimct
Post Number: 15
Registered: 08-2007
| | Posted on Thursday, July 11, 2013 - 02:53 pm: |
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Have you had any engine hiccups or starting problems from the air you've observed in the line?
If the pressure tests are good then there is no leak. As you mentioned, it may be the air you see in the clear filter is simply a stationary bubble. Since the fuel flow is so slow, the line doesn't get purged.
The other solution of course is to get rid of the clear plastic fuel filter. My experience is that they never fill entirely with fuel. Also, those plastic in-line filters are not C.G. approved. |
kevin stone
Senior Member
Username: kdstone
Post Number: 56
Registered: 01-2009
| | Posted on Thursday, July 11, 2013 - 04:25 pm: |
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The plastic filter is a temporary thing so I can see the fuel flow. I know they are not CG approved. I can see the air enter it and then exit through into the carb, with no hiccups at the moment. Earlier when this problem started I did have some idle issues. At that time I did find some air leaks which I took care of. I am wondering if what I see right now is air pocket which is slowly working its way through and will resolve itself. |
