If you have a copper fuel line, even if you think it's good, consider replacing it.
I have an Olson 34 with a Yanmar 3GM30F. I have been struggling with air ingestion issues since delivering the boat to Portland Oregon a couple months ago (410 NM journey). It was intermittent- but would result in the motor stalling. While diagnosing I discovered several minor issues in the fuel system and addressed them such as a leaking tank weld, a water- not fuel rated shut off valve at the tank that was leaking (if the handle is red, replace it- should be YELLOW) and few other niggly bits. After replacing everything else including the copper crush washers on the banjo fittings, I replaced the fuel line. Where I could see it- it was heavily oxidized.
I used a fluid extractor to put vacuum on the copper fuel line. It wouldn't hold vacuum... clearly leaking.
At 32 years, it's not surprising. When I removed it I found hairline cracks and witness marks indicating the tubing had been leaking fuel out and likely air in for a LONG time. I replaced with 1/4" Trident Marine fuel hose, type A1-15 (the stuff ABYC requires) and put small service loops behind the engine and near the tank so I have extra tubing if I need to cut ends off or bypass the Racor, etc..
WOW. The engine runs so much smoother. Best $70 in material I've spent in a while.
I have an Olson 34 with a Yanmar 3GM30F. I have been struggling with air ingestion issues since delivering the boat to Portland Oregon a couple months ago (410 NM journey). It was intermittent- but would result in the motor stalling. While diagnosing I discovered several minor issues in the fuel system and addressed them such as a leaking tank weld, a water- not fuel rated shut off valve at the tank that was leaking (if the handle is red, replace it- should be YELLOW) and few other niggly bits. After replacing everything else including the copper crush washers on the banjo fittings, I replaced the fuel line. Where I could see it- it was heavily oxidized.
I used a fluid extractor to put vacuum on the copper fuel line. It wouldn't hold vacuum... clearly leaking.
At 32 years, it's not surprising. When I removed it I found hairline cracks and witness marks indicating the tubing had been leaking fuel out and likely air in for a LONG time. I replaced with 1/4" Trident Marine fuel hose, type A1-15 (the stuff ABYC requires) and put small service loops behind the engine and near the tank so I have extra tubing if I need to cut ends off or bypass the Racor, etc..
WOW. The engine runs so much smoother. Best $70 in material I've spent in a while.
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