We have 12V72's and each engine has a pair of Racors. Changed to T heads with Parker gauges and pair on the port engine show almost full vacuum when running at any speed. Changed gauges, filters and worked valves all without anything happening. Help!!!
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Thread: Partial blockage in fuel line
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04-19-2019 02:10 PM #1Registered Member
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- Jan 2017
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Partial blockage in fuel line
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Re: Partial blockage in fuel line
If you have a vent which I suspect you do I would check that first to make sure its not blocked by something like spider webs or a bees nest. Also look for soft fuels lines that may have delaminated inside.
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04-19-2019 03:10 PM #3Senior Member
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- Apr 2008
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Re: Partial blockage in fuel line
You nigh want to blow back to the tank to be sure there isn't something on the pickup tube.
If that works biobor!GLORY Hull # 365
Northport, NY
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Re: Partial blockage in fuel line
The "Boogers" are usually in 90 degree elbows if you have any. Pressure (blowing them out) only moved them around. I had to take apart the lines and clean out. Was mostly behind the fuel manifold. I also cut my pickup tubes at a 45 degree angle on both sides (looks like a V from the side now) so there are no flats spots for something to block 100% suddenly. I also used a tool made for picking up small parts and tools that is long, flexible, and has a little claw on it and spent a day fishing for boogers around the pickups. Got quite a few.
Good luck. Probably a combination of small issues but like others said check the vents first.
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04-19-2019 05:29 PM #6Senior Member
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- Apr 2005
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- 2,771
Re: Partial blockage in fuel line
I had a similar situation years ago and it drove me nuts. It was an intermittent issue until one day on
a day cruise the engine shut down. When we got back to our dock, after much anguish finally the culprit
was found. The pick up in the fuel tank was picking up chunks of goop. We pulled the pick up and
cleaned it all up and ran a bunch of biobor into the tank. After changing the Racor filter several times
we ceased to have any recurrence of the problem. I do think however that all the suggestions listed
in the earlier posts have potential solutions as well. Good luck and let us know when you get it resolved
so that others may benefit from your efforts. Ahh, the fun of having a boat..........
Walt
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Re: Partial blockage in fuel line
Once had a generator return line become blocked with gunk that caused it to shut down. After trying everything we rad it from a jug and returned to the jug, and then worked from there. Have also had a flexible line delaminate on the inside which caused issues.
CRICKET
1966 HAT50C101
Purchased 1985 12v71Ns
Repowered 1989 with 8v92TI
Repowered 2001 with 3406E
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04-22-2019 01:41 PM #8Registered Member
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- Jan 2017
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Re: Partial blockage in fuel line
Okay; here's what we have done to date. First we switched the two high reading gauges on the port tank with the two reading normal on the starboard. Readings remained still high vacuum on port. Then we switched to draw from other tank. No change indicating it had nothing to do with pickup in port engine tank. Dropped the bowls on both Racors and thoroughly checked for algae; none. Pulled the diversion valve, opened the access ports and blew out all passages. Visually inspected same. Reinstalled and no change. Replaced one filter again; no change. The lines from the tank to the pumps are all copper except for a 3' section near the valve. It's all that's left. Will pull and replace on the possibility of a collapsed lining, otherwise, the boat is haunted.
We subsequently replaced the 3' of hose. $235 and no change in vacuum. There is nothing that was doable that has not been done. Checked with fill cap off so no blocked vent. Switched feed tank so no blocked pick up. Blown air under pressure through EVERYTHING; filter housings, lines, valves, everything. Unless there is some defect that causes a fuel restriction built into the Racor manifold that we cannot detect we surrender. Oh yes, Hatteras had nothing to suggest.Last edited by bigreelsc; 04-23-2019 at 03:41 PM. Reason: Final result
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Re: Partial blockage in fuel line
I appreciate you have changed tanks and issue persists so blocked vent won't be the issue but on my boat at least hatteras plumbed the fill line to the bottom of the tank meaning taking off the cap would still give high vacuum if the vent line was blocked. Your system might of course be more sensibly plumbed.
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04-26-2019 08:17 AM #10
Re: Partial blockage in fuel line
Is the engine performance affected?
1977 Hatteras 58' MY, Hull No. 304, 4-stateroom galley up model with 8V71TIs in Knoxville, Tennessee