Hey guys,
At the end of last year I pulled my tank to reseal everything, new hoses, and support as it hasn't been checked since 87'. After redoing most of the boat to make it to my liking I also installed a new Gaffrig fuel Sending unit as the original was intermitting fuel level. As I was changing out the Fuel level sending unit. I noticed debris and water in the bottom but there isn't an access big enough to suck out the nasty sludge that is in the bottom. Just looking for ideas to better access everything. My guess is just cut a hole and reseal with a plate screws and gaskets. This will also allow me to better fab a bigger fuel pickup for any future engine builds. 540,blower motor etc…. Currently running a 500ish hp 454. So i'm thinking 1/2 fuel line and I'd like to play with E-85 Later down the road. Any ideas please share! thanks!

you don't want to run e-85 in a boat

I hear that a lot. It's just a idea only because I'm running high compression and the cost of running race fuel gets expensive. And also my boat never stays in the water over night. If that makes a difference as I know E-85 is very moisture absorbent. And would also pump out what isn't used If i know the boat won't be used again for couple weeks or so. But I have worked with E-85 in street application with lots of success. But again only a idea.
But i'm wondering if anybody has used accessible fuel doors that allow them more room to access the bottom of the tank. Links would help.

Ayuh,.... I'm pretty Sure that what you want is against 100s of laws, federal, state, 'n Common Sense,....

Gas in a boat is dangerous enough, without cuttin' holes in yer fuel tank,....
If ya can't fix it through the gauge hole,... ya need a New tank,...

The Best things you could do are,....
Use good fuel Filters,... It'll catch any crud, 'n water comin' from the tank,....
'n carry a spare,...
The E-85 is a 'ell of a solvent, it'll knock loose things ya can't even see,...

If yer havin' fuel flow problems, check that the vent is clear, the diptube is clean/ clear, 'n the anti-siphon valve at the tank's outlet is clean/ clear,...
Other than the lines, the Filters will take care of the rest of it,...

Why are you using compression to build a 500is hp 454?? that combo should be happy on regular pump if done right,,,,

Yes you are right in many ways. I never had any fuel flow issues. Im just rebuilding all fuel component and wanted to experiment. Here's is a better description of what Im trying to explain. Sorry if It came off as a bit Confusing. In my mind it made sense. lol just didn't come out right. I figure I am trying to update the original 1987 design and gain better access so I can really make sure the tank is good and clean. Here is what I was trying to explain.




Now that the idea I'd like to strive for is visual. I am looking to install this on my 100 gallon tank. This is also for a Fuel Cell in a Car setup. Do you think I would have any issues running this in my boat? The tank itself is in ok condition. I was thinking win win because I gain access to clean/check the tank. (should only need to do this once hopefully) I have found screws in the bottom of the tank. Don't know how they got there? Could have been previous owner or fell in during assembly from the factory as Im sure we have seen stranger things. And here is the current. However it is dirty and just looking for a more simple and accessible setup. I do have a 8' round access water tight door above where the tank sits.




Before the tear down I was running 5 gallons of VP110 to every 20 gallons of 93. I only did this unsure of engine compression. Went through the carburetor and did our own little things to get it to idle better. With the huge cam it idled around 12-1300 rpms. After the carb rebuild we had it back to 850-900 and easier to maneuver. So I just changed the plugs checked the timing and played with it a little bit to get used to the boat and some seat time. But for the new build I'm pretty much keeping it with the same setup just a refresh. And was looking for a better alternative to a manufactured fuel such as vp/cam II or Klotz if anybody runs those. I stay close to home and don't run off too far. I was just looking for some extra squeeze out of it but i'm sure it's not worth running in the boat. I'm sure 93 is enough, I will know more in the week after I figure out current compression. I'm currently switching my Forced Induction car over to E-85 and my truck is compatible so i figured I would look into doing it in the boat as i'm changing and upgrading fuel lines and filters anyhow. Sorry for the long post but hopefully now you understand my thought process. thanks for reading. Please let me know your thoughts.

what your saying is if he didnt have crud in the tank.. but he does and he wants to get it out..

ive never played around with what you posted..have wondered about it though.. i do know, with some smaller tanks (not boat tanks) but weve used these before on freestyle skis before that do backflips etc, with zero leakage.. im sure its VERY dependent on the brand.. gaskets will be a huge issue on quality of them. but ive never used them on power boats.

I see what your saying to be able to check the tank etc, but what about just cutting a hole, cleaning it, and re-welding it?

so you are wanting to cut a hole in a 26 year old fuel tank full of fumes? just my opinion but you are money and safety ahead to just buy a new tank that has not had crap sloshing around in it and going on three decades of beating and vibration and abuse. as for the e-85, why? it is corrosive, all the new fuel tanks in cars are lined due to corrosion problems as are fuel system components. aluminum boat tanks are not and so far the 10 percent they add has destroyed thousands of boat tanks. if you need the octane to build power you need to reassess your combination as there are plenty of guys running way bigger power on 93.

I could re-weld. The tank is completely dry and has been opened just sitting in the garage. I would do a good wash on the inside before i would send it off to a welder.


The idea was only to max total HP and to do a little R&D on my own with E-85 and dyne tuning to see what the difference is. I'm not concerned with fuel consumption especially with the way I drive. I use it a lot in the car application especially under boosted with stock tanks and upgraded Fuel Pumps. Which makes it still just a idea in the boat. Just figuring I'm updating my entire fuel system and would make it stand even the harshest of fuels. But with my 100 Gallon tank I'm sure I will never fill as I've never had more then 30-50 gallons max. I could always get a smaller tank also and save a little on weight. And also I would be able to change from 93 to E-85 and Back to 93. I'm just in it to see if I can get any Top speed Gains.

Ok well after further investigation I'm still going to use E-85! ONLY TO CLEAN THE TANK! But I'm still considering the fuel door for easier access. Tank is in good shape overall, it just needs a little better fuel supply. 3/8" isn't going to cut it. New fill and vent lines and will be good for years to come. Thanks for the comments and advise. E-85 works best in v-drive and some jet boats in seems. Running our style boats isn't really convenient. But my car and truck LOVE IT!