ROADSIDE

Hi guys
First time user here so i don't know if i'm doing this right or not.
Hope someone can help, i got a omega hull with a K&B 67, the fuel tank is
higher then the carbie and it floods all the time, is there a valve or anything that i can
put into the fuel line that will stop this?

srw1960

If you cant move the tank to get lower than the carb you can get a small fuel pinch clamp and clamp the fuel line off when not running the engine..check tower hobbies I bet they have some fuel line clamps..could probably use a clothes pin until you can get a good clamp..also make sure you have shut the throttle all the way down when its not running thatll help keep fuel from flooding in

ROADSIDE

Thank you for that but what about when i try to start it? it normaly floods after first couple turns & locks up, in instructions they say to have fuel screw open 8-8 1/2 turns seems a bit to much only going on my ops40 i had befor that was only 3 turns

srw1960

That doesnt sound right at all..id start maybee 3 turns out and see how that goes..I bet that greatly helps with the flooding..try it and see how it goes

Dan S

srw is not far,
according to mecoa (K&B) site the HSN should be at 3 1/2 turns out from closed as a starting point.

Dan.

Ron Olson

My Feedback: (1)

Yeah, that's awfully rich for that carb.
On the other problem, yes, the fuel tank is way too high allowing the fuel to siphon into the carb flooding it. You're also placing the CG much higher which can give you handling issues.
I don't know what tank that you're using but Sullivan makes a Vee bottom fuel tank that holds 16 ounces that places it lower in the hull if you've got a mono which is what I'm assuming. That would be a good size anyway for your engine.

ROADSIDE

Thank you for all your replies i thought as much with the hsn setting and obviesly with exhaust pressure.
As to the tank i made the tank and yeah think that mite be the biggest problem, it is in a mono hull and
the tank sits under the exhaust shaped around it for more fuel capacity holds about 700ml  dont know what that
is in ounces....but think i better start with that.[8D]

Dan S

700ml would be 23.6 OZ, that's a big fuel tank depending how big the boat is.
it will give you some good run time, but it also give's you a lot of weight.

Dan.

ROADSIDE

G'd morning fellas hey i come up with an idea this morning to my fuel tank prob.....
If i make a small reciever tank lower than the carbie and discconect the fuel supply line
in between the fuel tank and the reciever tank in between start ups that would keep the small
reciever tank full enough for start up, but not syphon the fuel from the main tank until exhaust pressure
builds up and it starts to flow again.
What do you guys think?

srw1960

What your wanting to do would probably work but I realy think you would be much better off downsizing the tank a bit and relocating it...

Justaddwata

My Feedback: (3)

Out of curiosity Olly - if it is just during start up that the motor is flooding - could you adjust the boat stand so the tank is lower than the motor while you try to get her fired.

Would save you the extra hassle of trying to connect fuel lines once she is running.

ROADSIDE

You're probably right srw1960 but the carbie is only about 11/2in off the bottom of the V.
Thats probably the biggest mistake i made when i built it.So fuel capacity would not be alot to try & keep it under,
If some one could tell me how to put pics on here i could maybe try to show it.
I am just not up to speed with this yet its the first time...and can i just say all of you been great to talk to.
Justaddwata  it is to much of an angle, but my fuel supply comes out of the top of my tank so what i thought
is if i disconect the fuel line befor start up let all the fuel run back into the tank and reconect befor
i start the motor the fuel would not syphon through untill the engine either draws on the reciever tank or
the exhaust pressure pushes it through again

Ron Olson

My Feedback: (1)

Roadside, when posting pictures on this site, don't use the mormal reply box below but instead, click on the icon up here ^^^. That will take you to an advanced screen. In the lower left corner you can upload pictures from your computer.

ROADSIDE

Thanks for the info ron i will give it a go when i get back from vacation on 15th

ryan_t888

Any photos?

Never had this happpen to me on my tunnels.

Ryan

Ron Olson

My Feedback: (1)

Ryan, you've got what was my first though also as at first I was thinking OB tunnel with it having a .67 on it's an inboard mono. I had the same problem with my .45 Microburst even with the 16 ounce Vee tank. The problem is that the carb sets low positioned on the rear of the block instead of up high on the block. Either keeping the hull tilted forward and/or blocking off the fuel flow with something like hemostats or a spring loaded clamp is going to help from letting fuel siphon in when not running.

ryan_t888

Ah, I had to read it again. I swear I read tunnel with a 24 oz tank. Ah well.

Ryan

rcuk john

Sorry that I am a bit late in replying - take a look at [link]http://www.prestwich.ndirect.co.uk/fueltanks.htm[/link]. There is on the tank page a float chamber that the FRSV race boats use to prevent such problems. Their fuel tanks are up to 3½ litres (or the best part of ¾ gallon either US or UK versions).

ROADSIDE

Thanks John and all others,
the  web address you have sent is what my tank is in shape, but since i made the so called sub tank or reciever tank it solved all my probs.
I made up a tank which holdes about 6cc of fuel lower than the carbie, so when i start the engine, the 6cc tank is full and the main tank fuel
is blowen back into the tank so its not gravety feeding through to the recieving tank, until engine starts & exh pressure pressurises
main tank. All is good it runs I am happy......