ZX250 FUEL TANK VENT PROBLEM

[Mark L]

I bought a new ZX250 in DEC. The boat runs great until it builds up a vacuum in the gas tank. Then motor dies and I have to remove the gas cap to let air in. Then it runs great again. last night I removed the perco charcoal canister and bypassed by splicing the two 5/8 hoses together. The canister only had a hint of gas in it and nothing poured out of the canister or the hoses. The two hoses that go to the canister run 1 from the tank vent on the side of the boat that's in front of the gas fill lid. The other is from the gas fill spout to the other side of the canister. I have not run the boat yet with the perco canister bypassed that will happen tonight. But I am starting to think that may not have been the problem. Any ideas are greatly appreciated.

[JDI]

I have the same problem and did the same thing, bypassed the canister and I still get a vacuum with it just sitting under the carport. There are two other check valves on the tank that connect back to the filler neck. I'll try and add a picture of the filler because this is the craziest system I have seen.
I haven't spoken to the dealer yet, so there may be any easy or known fix.

[TAiken]

I've been having the same problem. I did find a vent hose was sagging and caught between the tank and livewells. I haven't been out since, so don't know if it fixed it or not. Some people told me to replace the anti siphon valve, the only problem is, I can't reach it without taking my whole back deck off. They deff didn't make it easy to work on these things yourself. I have never seen a fill system like that. I could tell that the vent tubes all went back to the main fill housing by sticking my arm up there. If you guys figure something out let me know.

[pajoe329]

I also was having all the same problems when I bought my 2014 skeeter tzx went back to dealer maybe 5 times to hopefully , knock on wood it's fixed , they said they changed the whole fuel system with the newer design , Know it runs great and I can put gas in her like normal , Go back to the dealer get it right

[utfisherman]

My 2014 FX20 is doing the same thing. Took it by last week and they said they would have to remove the rear deck to fix it. I have an appointment next week to leave it.

[Mark L]

I still have not run the boat sice removing the charcoal canister. I plan to get OTW this weekend. I will post if there is a difference.

[Mark L]

Took the boat out and ran it hard. Still had a vacuum build up but engine didn't die. I think I am going to reroute a couple of hoses to get them higher. JDI where did you find the PIC of the fill spout? Do you know what brand it is?

[Bass AHolic]

check for dirt dauber mud nests in vent line. those suckers even go in handle beside camper trailer door, seen that other day buzzing in.. gonna have to spray for wasps etc. I don't have em getting in gas vent as have screen inserts on Boat and the usual appliance panels on camper

[Mark L]

So I removed the vent hose hardware so I could have access to the hose. If you tried you could not push air down the hose to the fuel fill. You should be able to do that. I took my compressor and lightly blew air down that hose with the gas cap off. You could hear the check valve change positions. It is now easy to pass air into the vent hose. I plan to fuel up and run the boat tonight. I think that fixed the issue. One other thing I noticed its very easy to have your ring free or stabil run into the vent hose opening In the fuel fill. I will use a funnel from now on.

[Mark L]

So after using my air compressor to change the position of the check valve the tank is venting properly. Was on the water for about 4 hours yesterday and there was no vacuum built up when the gas fill lid was removed.

[OldTimer57]

Interesting problem. Quickleen and such do leave a residue when they evaporate. You'd think the fuel fill would be positioned with any vents on the top, rather than on the side or bottom where anything poured into the tank could seep in and then gum something up. Wonder if you can reposition that thing so that the two vent lines go in on the top side?

[JDI]

Sorry Mark, I didn't see your question until today. Not sure who makes it, but I hope that fixed the issue. I'm going to try the same thing tomorrow.

[Mark L]

Fished both days this weekend without any issues. The fuel tank is vented correctly now. So for me it just took blowing air from a compressor through the vent line. With the gas cap off. Seemed to open up the check valve. Very easy fix.

[B_Thompson]

So to clarify, you took the hose loose from the vent beside the fill and blew air through it?

[Mark L]

That is correct. I currently have the charcoal canister removed and the two hoses attached to each other. I removed the vent hardware and used my compressor and blew air through the hose with the gas cap removed. You will hear when the diaphragm opens.

[JDI]

I do believe this fixed the issue, I unscrewed the black cap off the outside vent and blew Air through the vent with the gas cap off and heard the check valve open up. I also have the canister bypassed and haven't had the vacuum issue since.
Thank you, Mark L

[WIIi]

Mark or JDI can you send a pic of the charcoal canister if possible... is the canister on the vent line or gas line???? I have the same dang problem with my 2018 518 with my Rude 150!!! Driving me nuts! I can’t find a pic and do not have a shop manual.

[JDI]

[JDI]

Was on the vent line, but like I said in the PM my issue was the check value.

[kry29]

Definitely sounds like some residue from gas treatments built up and made it stick shut. Atleast you know how to keep it fixed for future reference. It could also be an issue from putting treatments in after you pump gas if you do that