refueling overflow problems - Maxum Boat Owners Club

redondojoe · 06-23-2016, 04:35 AM

Hi All. I've had my Maxum 4600 for 7 years now and I seem to continue to have problems refueling as well as filling my water tank too. It is impossible to fuel without overflowing! I've tried everything...wrapping the fuel nozzle with a rag, trying to fuel slowly (with 418 gallons, that option takes way too long). On my last attempt, I had several huge waterfalls occur and I know for a fact that I still had 1/4 tank left. What's a captain to do? there is no logical warning. Pressure builds up LONG before it is close to being filled. Water and Diesel tanks have similar filling problems. I welcome any and all solutions!

Portholme · 06-23-2016, 11:14 AM

Likewise on 1a 2400SCR. Very frustrating and even worse for the environment than running a boat!!

mmwjr · 06-23-2016, 12:40 PM

My first thought is to verify the vent is not blocked but I must say I have the same issue with my 2400 SCR. I think one thing that contributes to this is that the fuel fill is at the same height as the vent while lots of boats the fill is higher. When filling mine it will shut off then I hear a gurgling followed by fuel backwashing.

I might try adding one of those whistle things you can put in the vent line that is suppose to change pitch when near full.

shrew · 06-23-2016, 07:23 PM

It's the Through Hull Vent itself more than likely. It is doubtful it's the line itself. Maxum commonly used a Perko Through hull Vent.

PERKO Thru-Hull Vent | West Marine

These have a screen inside which corrodes heavily. You need to replace it. When you do, you can determine whether you're line itself is also blocked, but that is rare.

dbriceno · 06-23-2016, 11:38 PM

Since it's really difficult to change the thru hull vents, what I did was to drill a hole though the center of the metal hull vent fitting (a decent sized hole). Previously my water would be a geyser after I was 1/2 full. The hole completely fixed it. I had one tank that I could only put a few gallons in at a time before allowing the air to come out the fill. Otherwise, like you, the fuel would overflow. My other tank was a bit better. I could use a slow pump and leave it on the first notch of the filler handle without a spill. I haven't fueled up since adding holes to the diesel vent. I'm hoping the fuel vents work as good as my water.

Good Luck

shrew · 06-24-2016, 01:43 PM

I just got done replacing all 11 through hull fittings on my boat. All of them should be accessible, though some not initially as apparent as others. I had to remove the toilet paper holder in the head to access the through-hull discharges for the shower drain, head sink and midship bilge pump. I had to remove the fridge to access the galley sink drain through-hull.

There is a reason there is a screen on the through hull.

iantan · 06-27-2016, 11:26 PM

I had exactly the same problem on my 4600, I replaced the vents and all fixed. They aren't too hard to get to so if you plan on fixing/replacing yours let me know and I'll give you details on how to access them.

Ian

dbriceno · 06-28-2016, 01:29 AM

Ian, please give some details. I'd like to replace the vents I drilled out

iantan · 06-30-2016, 08:13 AM

Sorry for the delay in replying, I'm away in Europe on holiday - and also looking for a new boat but that's a different story.

Anyway, I'll post a reply when I get back if that's okay as I know I have some photos. I could you a verbal description if you want to do the work in the next two weeks, let me know.

dbriceno · 06-30-2016, 04:27 PM

No rush. Thanks

Foxy 01 · 07-13-2016, 08:38 AM

Same problem with my 35' only the port side which tends to blow back. I would appreciate a fix thanks.

Portholme · 07-13-2016, 08:48 AM

I've been thinking about this relating to another issue and what I'm going to check on mine is if there's any water in the loop of tube for the vent. This might create a vacuum.

Foxy 01 · 07-13-2016, 08:11 PM

Thanks I will be away for a week will have a look when I get back could be something that simple.

BillS · 01-27-2017, 09:18 PM

I have a 4600 SCB and drilled out the thru hole vents. Despite never filling all the way up, I regularly get multiple 2-3 foot high "geysers" of diesel fuel suddenly spraying out out while fueling, in rapid succession, with no warning, while filling up. I have learned to "listen" as I am filling and back off, but sometimes its too late. I have even gotten drenched in the process. One time this happened while there was an EPA breakfast at the marina I was filling up at. I handed out $20 bills and cups of dish soap to some guys with small boats and asked them to go churn up the water to disperse the huge slick. This is not good. Despite being able to minimize it, it still happens on occasion without warning. I do plan to replace all of my thru hulls. Somehow I dont see that addressing the issue, as I did drill out the existing ones.

iantan · 01-27-2017, 10:42 PM

I guarantee it will be blocked vents. When I bought my 4600 it took ages to fill up the water tank. As you describe I would put the hose in and start to fill up and would wait for the rumbling sound before I got the 3 ft geyser you mention.

It wasn't a problem with the water but when it started happening with the fuel that was an issue.

The starboard vents are accessible behind the sofa, there are 4, I think, bolts the hold the back of the sofa in place, remove the sofa back and then remove the ac vent, you'll see the vents behind there. You'll need someone on the outside to hold the vent and stop it turning. There was silicone on mine so a bit difficult to remove.

The port vents are down the side of the fridge, you will probably need to remove it.

Good luck.

donald · 01-28-2017, 04:11 AM

I have the same problem with my 2400 SCR!
I am going to try a fuel fill ck valve in both the water and fuel tanks!
They fit in the fill hose at the tank!
If anyone tries it let me know how it works!
I am out of state and of line for several days so wont be able to get back to any replies until I return!
Thanks and good luck hope someone has success in finding a fix!
Don

shrew · 01-30-2017, 02:53 PM

Quote:

Originally Posted by Portholme

I've been thinking about this relating to another issue and what I'm going to check on mine is if there's any water in the loop of tube for the vent. This might create a vacuum.

The fuel vent loop goes ABOVE the vent, not below it. If water enters through the vent, it will rise the tube, then should drain back out again. It would be very, very difficult for water to enter, then rise up and around the loop to drain into the tank. If the loop were below the vent, then it would create a trap and any entering water would essentially block the vent and a vacuum would occur. If the loop is below the vent it was improperly re-installed by a owner doing DIY.

For those with this issue, I assure you it is the fuel vent itself. There is a screen on the inside. It corrodes over time and restricts the passages. Insects have also been known to make nests there. If not check whether there are any restrictions in the fill tube.

mrt214 · 01-30-2017, 06:42 PM

You could use a shop vac on vent outlet. it should get anything out that could be clogging it including dead spiders.

Okieboat · 01-31-2017, 11:27 AM

I have a similar but compounding issues with the water tank on my 3900 SCR that has me scratching my head. When I first bought it I filled it up with water and didn't think much about it. I went below and I found a huge hump I front of the couch. I peeled the carpet up and the tank had expanded so much that it ripped the plywood decking off the screws. I ran the shower and sink faucets to remove some water and it went down. I thought maybe the vent was clogged so I used my power washer and there must have been a muddober nest inside it. Now when I fill the water tank water will come out of the vent if it's overfilled. It will still bow up the floor below. I now use the aft shower head to drain it. The second more recent issue which may or may not be related is when the potable water breaker is on the pump seems to run a lot, and the water tank shows empty after a day. I cannot find any signs of a leak in the cabin, and the bilge seems normal (for some reason it always has some water in the bilge). Could there be a part on the toilet that is malfunctioning and passing water? The bowl does not show signs of water running. I am not a great mechanic, minimally adequate at best. I would like any pointers anyone might have. One issue is that I live 3 hours from the lake and any parts I need to make repairs I have to order and take with me as there is not a marine store nearby. I typically buy to many parts, get to the lake and spend a day working on it, and In the end either I didn't have the right parts, or I was completely off base with the problem. Expensive and frustrating to say the least. I hope I am posting in the proper place, if I am not I apologize, all help would be very much appreciated. Not just by me but the whole family that seems to be waiting on me to fix it.

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