Info needed, Im getting air in the fuel line.

[Pat Nannery]

I have a 1993 Hunter that has suddenly started stalling.Ive changed the filters, removed the fuel feed tube in the tank to check the screen(there wasnt one), all to no avail.Strangely, it may be happening after I cross a wake or hit a wave. Yesterday, I ran the Yanmar at the dock, under load, for about one hour, no problem.Tonite, I went out for 2hrs, engine stalled twice, had to be bled at the fuel pump to get it running, there was air in the line on both occasions.Anyone have a similar problem?

 

[Andy Falls]

Water in your filter, Air in your lines

Do you have a water/fuel separator? If you do, and its partially filled with water, the wave you hit may be causing the water to get sucked into the engine instead of fuel. I guess it could happen in the tank.another possibility is that you are sucking air in due to a crack in a fuel line.sounds nasty, but have someone (poor soul) blow on your fuel line and see if you can find a leak.

 

[Ron Dague]

Air Leak

Air can leak in, where fuel doesn't leak out. It seems odd, but you can have a small hole or crack which allows air to be drawn in, but no fuel will leak out. So it can be hard to find, since you don't have any dripping fuel to show you where it is. Remember, that there is almost no pressure in the fuel line, it is sucking the fuel into the engine, not pushing it from the fuel tank. So it will suck in air, but not "blow fuel out".It also could happen if the seals at the filters aren't properly seated. I replaced all the fuel lines on a h34, to prevent just this type of problem.It might be easier to replace the fuel line, at a cost of $1.75 a foot, you can't have more than 10 feet total.

 

[Steve Dion]

Cheaper to just replace the fuel line.

Pat:It may be cheaper to just replace the line from the fuel tank to the primary filter and then from the primary filter to the engine. This is a quick fix and if it works you are home free. If it does not then you have spend only a few buck but have eliminated one source of the problem. Be sure to check the fitting on each connection. DO NOT USE TEFLON TAPE on the joints. If you have not replace the primary filter recently I'd do this next. Be sure to put some lube on the gasket when you replace the filter.The next spot is at the engine. There are a couple of the copper o-rings (bleed screws). These should be replaced after each service. Once they have been compressed they are really not suitable for reuse. The last thing at the engine is the secondary fuel filter. This is the alum bowl. Be sure that there is not a leak at this bowl.Once you have checked out all of these point and you still have a problem, you may need to call the Yanmar Man.

 

[Carl and Juliana Dupre]

This Is Probably Obvious, but....

...what is the fuel level in your fuel tank? Pickup tubes seldom go to the bottom of the tank; the fuel level could get close to the bottom of the pickup tube while the tank still has quite a bit of fuel in it. When the fuel level gets near the bottom of the pickup tube, the sloshing around that will naturally occur while out in wind and waves will periodically expose the bottom of the pickup tube to the air, and an air bubble will be picked up into the tube. At the dock; no wind/waves, no sloshing, everything is fine; out on the water; wind/waves, sloshing, air bubbles.We learned this "reality" no-fuel level of a club boat we were sailing the hard way one day, and in less-than-pleasant weather conditions.Carl and Jules/v Syzygy