Gas Engines

[Tim Reeves]

I have just purchased a gas engine after using nitro for many years. I know I need to change the bung, but there does not seem to be much info for plumbing in gas engines. I have come across the term of syphoning and putting a loop in the fuel line. Does the loop go in the filler line or the feed line. If anyone can shed light on this subject, it will be helpful. Thank you.

[Snorbitz]

I run a simple 3 line system. Tank-Carb, Breather and a dedicated filler line. Never had a problem. No need to pressure the tank with a gas engine.

[Ultymate]

Don't ever pressurize petrol tanks there's a big fire hazard if you do. I too prefer a 3 line system rather than having a "T" junction and refuelling through the feed line so as Shuglu tank to carb, a breather, and a dedicated fill line which you can put a second clunk on if you want to be able to de-fuel. Personally I don't use the second clunk preferring to leave fuel in as the carb diaphragms and flap valves tend to dry out if left empty. If you're going to fly aerobatics then wrap a loop in the breather line to lessen the chance of syphoning when inverted.

 

P.S I always use a felt type clunk filter in the tank cheapest from your local chainsaw shop 

Edited By Ultymate on 08/10/2010 11:08:34

[Tim Reeves]

Thank you for the replys, most helpful.

I am running a 3 line system as prefered with nitro. With the breather line, (may be being a bit dumb here) surley that will have to have a bung in, poss with a very small breather hole or is it air tight? 

[Ultymate]

The breather line is open to allow the tank to "breath", the fuelling line is bunged.

[Tim Reeves]

Thank you for you help. Got my head around it now. Starting the running in, works fine with the 3 line system.

[tom clarke]

hi people, i am doing a peak models yak with dle 30 motor and and the cannister goes inside the fus, the conern i have is that the pipe passes just an inch below the fuel tank with just 3mm ply seperating the hot pipe and gas tank..... will the heat from the exhaust go up to the tank and cause a problem?

[Delta Whiskey]

I use the 3 line method too, but after filling I put a bung on the breather line too, am I therfore making the tank squash inwards as fuel is used? Never noticed any problems.

[tom clarke]

hi delta, you should leave one pipe open so air replaces the fuel as it leaves the tank, i use 3 lines on my 50cc, 1 to engine 1 to fill 1 open breather, i have a one way valve on the breather so it doesnt drip fuel everywhere but can still draw air inwards

[Ultymate]

DW if you don't have an open vent you'll eventually damage the tank. The pumps which are built into the Walbro/ Tillotson carbs will suck the fuel out of a fully sealed tank but it's definitely not best practice