Lately, I have noticed fuel accumulating on Top of my high-pressure fuel pump. I cleaned it up to see if I could see exactly where it was coming from but I see any particular place. But I suspect it may be coming from port where the fuel line attaches to the top off the fuel pump. Does this mean my fuel pump needs to be rebuilt?
Fuel leak on my Yanmar 3GM30F engine in my 1987 Hunter 34.
- Thread starter Randy Miller
- Start date
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 22,509
The usual leaks on the fuel pump are the hoses or fuel lines running from the pump to the injector. If the lines are steel, check to see if they use a copper compression fitting. It is recommended that these be changed each time they are loosened. If you have hoses, then check the clamps. If they are spring wires, replace them with proper hose clamps.
Sometimes, after you clean up the spilt fuel, place a clean paper towel on the top of the pump. Start the engine, then stop it. You may get a clue as to where the leak is located.
Sometimes, after you clean up the spilt fuel, place a clean paper towel on the top of the pump. Start the engine, then stop it. You may get a clue as to where the leak is located.
No. The leak has NOTHING to do with the operation of the pump. If your engine is running reasonably smoothly, the pump is only leaking, and not malfunctioning.
Before you do anything, YOU MUST find out where the leaked fuel is coming from. Do this by wrapping small pieces of toilet paper or paper towel around each tubing joint on the pump. Tape in place if neccessary. Run the engine at the dock for 10 minutes and see what gets wet. Once you find the source of the leak, report back here for further discussion.
Take it slow. Don't listen to friendly advice from drunks on your dock. You'll find the leak but it is slow and dirty work. The alternative will cost you $thousand$
Sounds like good advice from both of you. One thing to keep in mind since both of you have mentioned this. I haven't run the engine. This leak develops without running it. I like the toilet paper idea.
The fuel lines that go to the injectors are metal tubbing and a threaded nut that tightens down on the pump side. It is a very tight area and I think I may have to remove the heat exchanger to tighten them. I looked on an engine exploded view and it didn't look like there was a seal of any kind. Thanks in advance for all of your help.
The fuel lines that go to the injectors are metal tubbing and a threaded nut that tightens down on the pump side. It is a very tight area and I think I may have to remove the heat exchanger to tighten them. I looked on an engine exploded view and it didn't look like there was a seal of any kind. Thanks in advance for all of your help.
Hi Randy.
First identity the location of the leak.
If it is on the low pressure side (feed from tank to pump), it will be a small leak or seep.
If it is on the high pressure side (from pump to injectors), it will be larger.
Paper towel will be a better tool than tissue or toilet paper.
RE: I suspect it may be coming from port where the fuel line attaches to the top off the fuel pump.
When you find the leak, DON'T just try to tighten it down.
The filter top is made of a soft metal that could strip (in fact it could be stripped already).
Do the job properly.
Remove the leaking part (line or fitting or fuel pump) and inspect.
If it is copper washers, buy new ones off the shelf at an appropriate supplier ) not Yanmar, anneal and replace.
If it is a cracked or worn steel line, take it to an appropriate shop and get a new one made.
Or buy one from Yanmar if that is easier.
If it is a stripped thread on the fuel pump, as Ralph has suggested, report back here.
With photographs
Refit part. Bleed system.
Wipe your hands and congratulate yourself.
gary
First identity the location of the leak.
If it is on the low pressure side (feed from tank to pump), it will be a small leak or seep.
If it is on the high pressure side (from pump to injectors), it will be larger.
Paper towel will be a better tool than tissue or toilet paper.
RE: I suspect it may be coming from port where the fuel line attaches to the top off the fuel pump.
When you find the leak, DON'T just try to tighten it down.
The filter top is made of a soft metal that could strip (in fact it could be stripped already).
Do the job properly.
Remove the leaking part (line or fitting or fuel pump) and inspect.
If it is copper washers, buy new ones off the shelf at an appropriate supplier ) not Yanmar, anneal and replace.
If it is a cracked or worn steel line, take it to an appropriate shop and get a new one made.
Or buy one from Yanmar if that is easier.
If it is a stripped thread on the fuel pump, as Ralph has suggested, report back here.
With photographs
Refit part. Bleed system.
Wipe your hands and congratulate yourself.
gary