fuel tank maybe blocked?

[rissile86]

Well, i'm having trouble filling up my 70ltr underfloor tank in my poly, it seems its blocked, i go to fill it up and it just dosnt want any fuel (just comes out the overflow
). What the best way to check and how? i rather just try and fix it myself so i can take it out tomorrow in confidence. thanks in advance

[chin]

It's a common complaint rissile, depending what model hull you have.
It's usually caused by low points or even loops in the breather hoses, which allows fuel to sit in the hose and stops it "breathing"
There are 2 breather hoses on my 4.55, one from the front of the tank, and one from the rear of the tank. One goes to the breather itself on the transom, the other goes to the filler neck, which acts as a second breather.

It was a hassle, but I managed to remove most of the loops and low points out of both hoses by shifting and relocating them, and it fills up at the bowser no problem now.

[jeb820]

Mine is a bit the same, I found that if you fill it up slowly you can get the fuel in. but I am going to investergate the breather hose thing and see if I can improve that.

[Pirate Pete]

Chin is spot on with his reply.

In my 5.3 spent some time & even used a camera to take some pic where I couldnt see & the problem was with the breather hoses. I managed to work my slack back into the transom & then used some wire ties to hold things in tight so they rose from the tank to the breather.

If you want I could find the old posts & put the pics up again.

[rissile86]

thanks for the replys, i think i will just take it back to the shop and let them deal with it.

[BigFella]

,,,, thats the best way to go. Take it back, 'cause if the dealers dont get the feedback, we cant pass it along to the factory, and the factory dont realize they may have a problem! They have had several new boys in the assembly section over the last few months, and once the floors and hatches are screwed down, no-body can see the loops or crimped breather lines!
Some builders put loops in the breather lines to slow down the access fuel from spewing out when re-fueling. Doesn't excuse the problem though, good luck with the fix!

[polyFrank]

Hi Rissile86.
A few years back after buying my 5.3 poly, I looked at this website to see if anyone else was having problems with filling the fuel tank. I noticed Pirate Pete's post on breather tubes, but as far as I could see that wasn't a problem.

I got sick of standing at the servo, so I bought some 20 litre fuel tanks, fuel hose and squeeze bulb. Put the containers on the back seat and siphoned the fuel in. A longwinded way of filling the tank, but it works.

To make sure I knew how much fuel to put in for the first time. I put a spirit level on the boat floor and wound the jockey wheel down. So the fuel was level in the tank and I could see how much was in there by looking at the back of the tank.

The boat is parked on level ground and I had to lower the jockey wheel to the very bottom, way below the height the trailer would be hitched at.

Therefore on my rig the fuel is more to the back of the tank at the servo and once it reached the bottom of the filler tube it won't take anymore.

I don't know if all polys have the hatch above the back of the tank, if yours has then look at the fuel level.

Cheers
polyFrank

[polyFrank]

Did a bit more work on the fuel filling issue. Took the left bait tank out of the top of the transom, which gives access to the breather hoses where they come up from under the floor.
The breather hoses on my poly are ok as far as sagging goes in the tank area. They exit that area through holes just above the height of the tank. Getting hold of the front breather hose through the opening where the bait tank was. I could lift it a good 150mm. So I slackened off the plastic vent the hose is fitted to, put a bolt through the transom pulled the hose up and tied it to the bolt. This rotated the plastic vent 90 deg. So the hose now comes up from the bottom and does a 90deg arc to the vent. It must have sagged heaps after leaving the tank section.

The other thing I did was work out exactly how much fuel was in the tank, when the fuel level reached the bottom of the filler tube, with the boat hitched up. That is 75% full. It’s at that point I’m assuming the auto stop on the fuel pump will activate. If so filling at a slower rate will be the go.

As I said in my last post I have not filled up at the petrol station for ages. I will the next time I need fuel to see if my breather hose fix did anything.