Chris Nicastro

My Feedback: (3)

I have a three tank set up in a cat with a Zenoha engine and Walbro carb. The carb has the bulb to prime and the high low needles, pretty typical stock carb. Anyhow what I'm seeing is that the fuel tanks develope a vaccuum after a few minutes and then starve the engine. If I relieve the vac then all is fine again for a few more minutes. The standard single tank system does not need an additional gas line or vent line and it works fine. My set up has a Dubro Gas quick fill valve and a T to a vent for filling the tanks. So why does this set up require a check valve or something to keep the vac to minimum? The two line single tank didnt?

Does anyone know if the Walbro WT carbs pump pressure at all back into the tank? I'm not seeing that if so.

Thanks,

Chris

webdr

Just wondering, why do you say a single tank setup does not need a vent? I would think that not running a vent would definately create a vaccuum, right?

Believe It

a hard tank needs a vent....

martno1fan

All gas tanks need a vent or this is what happens ,why do you want a 3 tank setup for one motor?wouldnt two be enough or even one or maybe a bag ?.

Chris Nicastro

My Feedback: (3)

Well on a cat to distribute the fuel load evenly and very low in the hull I have a pair of 10oz tanks and 2oz header tank. They are velcro'ed to the hull and I can move them to adjust CG.
I thought the carb would supply some sort of minor back pressure since there is a return line but I guess this is not the case. The single tank must have a way to breathe through the cap I guess???

I guess thinking through it I see there obviously needs to be a vent to atmosphere and just for kicks maybe a check valve to keep fuel in the line. Still puzzled about the single tank and no vent though but hey I'm not using it now so there it is.

Thanks!

Chris

martno1fan

My tanks have vents in the cap,one blocked up and 15 mins into running the motor died,this happened a few times and baffled me for days but i finally found the problem thanks to a mate .

mauian

regardless of how many tanks they all have to vent. Most if not all Gas motors dont provide pressure to tanks, so they have to be vented. I f you were able to make it work with 2 then that tells me you had a leak somewhere providing the venting. Like Mart said in his post it will eventually lose fuel.