Does your fuel tank have a strainer in it?

[Captain Graham]

I have a 27th sailboat with a 18 HP diesel.
When I increase the rpms the engine would start to die.
Lowering the rpms it would go back to running well.
So at high rpm the engine was not getting enough fuel.
I checked the 2 filters the external racor and the one on the engine they where just a little dirty so I changed them.
Still had the problem so I thought maybe the tank had a big chunk to something blocking the fuel outlet pipe at high rpms.
Emptied and cleaned the fuel tank did not find anything so I looked at the fuel outlet pipe.
To my surprise I found a small strainer inside the outlet pipe that was clogged.
I had no idea some tank manufactures put strainers inside the outlet pipe.

So I removed it and added a clear filter before the racor filter where I can see it.
The filters are
1. Clear filter 60 mil (to catch the big stuff)
2. racor 10 mil filter (to catch everything including water)
3. filter on the engine 25 mil. (really does not do anything but that is what the manufacture uses)

You may want to check to see if you have one and clean it before you have a problem.

[wrwakefield]

Good catch and root cause analysis. [And thankfully rather unusual from my experience in the boats I’ve had.]

One that got me on a different boat was the fuel with entrained air when the tank reached ~50%. I discovered a pinhole [corrosion] at that level on the pick-up tube in the diesel tank…

On yet another boat the symptoms you described were caused by the internal layer of good [but old…] Type-A fuel line collapsing- thereby greatly reducing fuel flow- under higher throttle [suction.]

All these causes are simple to describe, but take a lot of time and effort to discover.

Glad you found yours; Another contributing factor to add to the list…

Cheers, Bill