Fuel pick-up issue?

[Heron]

Background: My Starboard tank has been emptied and filled several times since we've had the boat. Never an issue.
Last week while cruising the engine stopped 1/2 mile out of Oriental harbor in rough conditions with 1/2 tank. Switching to the port tank (running through the same multiple filters) started things right up again.

All filters are new and no gunk is showing there in my (several) water separators with visible bowls.

Everything is fine on the port tank. Ran for several hours on that tank and made a switch to starboard and the engine died again.

Filled both tanks and symptoms remain.

I'm suspecting a fuel pick-up clog. There is a good chance I won't be able to access to top of the tank to pull this.

Thinking of running some compressed air down the pick-up line in hopes it will clear the blockage and hopefully some chemical treatments will dissipate this.

Ideas??

 

[O C Diver]

Be careful. If the tank is full, a significant volume of compressed air may blow fuel out the tank vent when the blockage clears. A bicycle tire pump with it's low volume and slow pressure build up might be a safer approach.

Ted

 

[Heron]

Be careful. If the tank is full, a significant volume of compressed air may blow fuel out the tank vent when the blockage clears. A bicycle tire pump with it's low volume and slow pressure build up might be a safer approach.

Ted

Good point Ted. I have a small pancake compressor that I can adjust the output on...I'll start easy!

 

[LarryM]

Steve,

If the engine stops quickly when switching to the starboard tank, it is probably the fuel pick-up or something in the piping between that tank and the selector valve/filter.

I would also check the fuel vent for that tank. If it is clogged, it will also stop the engine. A quick check for this would be to remove the tank filler cap and give it a try. If it runs, it means the vent is clogged.

Good luck, hope it is something simple and obvious.

 

[HopCar]

I had the same problem. I had to install a deck plate over the pick up tube to get it out. I expected to find a screen on the end of the pickup, there wasn't one. I went crazy trying to figure out where the blockage was. I finally unscrewed the tube from the fitting and the screen was at the top of the tube. It was full of crap. I threw that damn screen half way across the canal.
If you end up pulling the pick up tube, get rid of the damn screen. Let the dirt come through to your fuel filter where it is easy to deal with.
I ended up putting deck plates over my fuel level senders as well.

 

[jleonard]

A dinghy foot pump would work well for attempting to clear out the pickup tube. Lots of volume, low pressure.

 

[Larry M]

If you're going to tap into the fuel system line at the tank to pressurize/blow back into the tank, I would shut the fuel off at the tank and disconnect the fitting on the filter side. Slowly open the valve to see if fuel drains into a container. I'd do all this after you have checked the vent for blockage. If fuel does come out work your way toward the engine and look for an air leak.

 

[psneeld]

Fuel hoses can delaminate and collapse under slight vacuum....

After the pickup has been resolved.....just an idea to remember.....

Some tanks can have antisiphon valves on them that can stick...and hamper testing such as seeing if a tank will drain through it just by siphoning.

Rule number one in my book of troubleshooting....check the simple first...it usually is.

 

[Heron]

Thanks all for the suggestions.....I'll probably tackle this tomorrow and report back...

 

[kartracer]

Good Luck,, I am going through the same thing for six weeks now with no luck. Changed fuel lines, filters, values, only thing left is fuel pump, and that will be done this week.

 

[Heron]

Follow up:

Success!

A few quick blasts of compressed air cleared the pick-up.....
I'm guessing any blockage was a residual affect of the asphaltine problem I dealt with a few months ago.. I've been using dispersant chemicals, but guess the screen still had build-up as Parks mentioned.

Ran a polish for awhile to get everything flowing and circulated then ran the engine for 20 minutes with no issues or any vacuum readings showing on the Racor gauge..

Fixed!

 

[HopCar]

Nicely done! I'll remember that trick.

 

[FF]

IF you still have a problem I would again consider an air leak.

With a borrowed outboard fuel tank with a couple of gal of diesel, its not hard to disconect the fuel line at the tank valve and pump some pressure in the system.

A really slow leak will require you wipe every fitting and part , and then tape a paper towel strip to each.

A couple of hours of pressure will show the leak.

IF the system is properly done , you may have to cap the return line to the fuel tank to maintain pressure.

Most outboard tank squeeze balls are limited for overpressure , so pump away till you hear it bypassing.