I own a 1984 31 hunter with a 2gmf Yanmar, I am having a hard time finding a fuel leak, After running the boat I get deisel fuel in the bilge under the steps. It is not leaking in the engine compartment. I dont see any apparent fuel leaks from the tank/fuel line. Any suggestions?
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Frank Pratt
Things to Replace
Here are a couple of idea's. 1.) Replace the copper washers at every joint, even a small cut or scratch can cause a leak. 2.) Wipe down the engine and spray the suspected area with one of the deodorants that have powder in them. Run the engine and check for leaks. My leak was at the priming pump connection.
Here are a couple of idea's. 1.) Replace the copper washers at every joint, even a small cut or scratch can cause a leak. 2.) Wipe down the engine and spray the suspected area with one of the deodorants that have powder in them. Run the engine and check for leaks. My leak was at the priming pump connection.
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Ed Schenck
Another tip.
The last time a Yanmar mechanic worked on my diesel he tightened every possible connection. Said it should be done a couple times a season, that normal vibration will loosen anything and everything.
The last time a Yanmar mechanic worked on my diesel he tightened every possible connection. Said it should be done a couple times a season, that normal vibration will loosen anything and everything.
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Dave Winiker
Fuel Leak
I found a nagging fuel leak between the fuel supply hose and the fuel pump banjo fitting which is located at the rear left side of the engine (facing aft.) Since tightening a couple of weeks ago the leak appears to have stopped.
I found a nagging fuel leak between the fuel supply hose and the fuel pump banjo fitting which is located at the rear left side of the engine (facing aft.) Since tightening a couple of weeks ago the leak appears to have stopped.
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Bryan C.
Probably the secondary fuel filter
My guess is the source of your leak is the secondary or engine mounted fuel filter. This is the only place in the fuel system where a part of the line is dissassembled for maintenance. If the retainer ring is not sufficiently re-tightened, I get fuel under the engine while it is running. I have to tap it with a hammer and screwdriver to sufficiently tighten it. Test as suggesed by the others, or wipe the secondary fuel filter cylinder clean, run the engine, and see if it is wet.
My guess is the source of your leak is the secondary or engine mounted fuel filter. This is the only place in the fuel system where a part of the line is dissassembled for maintenance. If the retainer ring is not sufficiently re-tightened, I get fuel under the engine while it is running. I have to tap it with a hammer and screwdriver to sufficiently tighten it. Test as suggesed by the others, or wipe the secondary fuel filter cylinder clean, run the engine, and see if it is wet.
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Ken Palmer
Check the bleeder screw
The screw on the secondary filter is a problem area. There is a washer that should be replaced (mine was nylon, not copper), and if the screw has been over-tightened over the years, it will strip the threads and leak fuel when running the engine. I bought a new housing for $39. Ken Palmer, S/V Liberty
The screw on the secondary filter is a problem area. There is a washer that should be replaced (mine was nylon, not copper), and if the screw has been over-tightened over the years, it will strip the threads and leak fuel when running the engine. I bought a new housing for $39. Ken Palmer, S/V Liberty
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Roger Mummah
You Will See Fuel On the Secondary Filter
If either of the screws on the top of the Yanmar fuel filter are leaking you will see the wet fuel on top of the filter housing. If the area is wet with fuel, just dry it and run the engine and see where it comes from. There are two screws on the top of the housing. One has a fiber washer and the other has a copper washer. I replace either washer every time I loosen the screw. They are not expensive. Do you put a clean white absorbent pad under the diesel? We can easily see anything that drips from the diesel by looking at the white pad for signs of drips. Note the color of the stuff. You can use an inspection mirror to look up under the engine to see where the drip might be coming from. We have had two leaks over the years. Once it was the fuel lift pump and we replaced it. The others have been the screws on the top of the fuel filter housing. We use new seals/washers on them. Good luck. Roger and Susie Mummah s/v Endless Summer
If either of the screws on the top of the Yanmar fuel filter are leaking you will see the wet fuel on top of the filter housing. If the area is wet with fuel, just dry it and run the engine and see where it comes from. There are two screws on the top of the housing. One has a fiber washer and the other has a copper washer. I replace either washer every time I loosen the screw. They are not expensive. Do you put a clean white absorbent pad under the diesel? We can easily see anything that drips from the diesel by looking at the white pad for signs of drips. Note the color of the stuff. You can use an inspection mirror to look up under the engine to see where the drip might be coming from. We have had two leaks over the years. Once it was the fuel lift pump and we replaced it. The others have been the screws on the top of the fuel filter housing. We use new seals/washers on them. Good luck. Roger and Susie Mummah s/v Endless Summer
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Bill O'Donovan
Not too tight!
Don't overtighten the bleed atop the secondary fuel filter, or it will strip completely and flood everything. I've done this twice, to my everlasting annoyance. The deep philosphical question here is: What is the correct tightness just before one strips the threads? Beats the hell out of me.
Don't overtighten the bleed atop the secondary fuel filter, or it will strip completely and flood everything. I've done this twice, to my everlasting annoyance. The deep philosphical question here is: What is the correct tightness just before one strips the threads? Beats the hell out of me.
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