Classic Australian Wooden Power Boat Association

Ray, the process for starting I had Greg forward to you assumed that you always used an Electric Pump delivering a continual volume at around 2 1/2 pounds of pressure once you were running. You don,t need to flood the engine before starting so that was why the pump was turned off once primed until engine fired.
Amal carbs need a constant flow to function correctly, mechanical standard pumps have a pulse flow , not what is required. A motorcycle tank always delivers a low pressure with a slight variation depending if fuel level is hi or low.

Why would you pump anything back to the Tank , that,s only required on todays injected engines because of the hi pressure and flow required and if you were to return to the tank that line would require a Pressure regulator to maintain the correct pressure at the carbs. Remember constant flow and constant pressure at all times.

Good luck
Wildwoody1

Ray I have little skiff called NIAD. Did exactly the same thing to me. I gave up and its been sitting in the shed for ten years. It was quite a successful bboat in its day.
My lewis skiff ff sure. Does it as well. The problem with it was too much overlap in the camshaft.
The exhaust pipees in the water created too much back pressure.
I solved the problem by getting a couple of people to hold the back of the boat up out of the water as I went to start it. I wouldnt turn it off till I finished my run.
Persevere with it. It will be something stupid.

Many of the engines that used either Bike Carbs or in some cases SU,s had them modified to function more as a low pressure Injector than a Carby. Work great if you know what you have and treat it accordingly. That,s why history sometimes makes things easier to understand.

Wildwoody1

The electric pump was pushing fuel past the needle and seat when the return line was blocked off, causing fuel to drip into the boat, I didn't get to run it with the return line blocked to see if the flameouts stopped. I'm sure it's a 7 psi unit, at least thats what i was told. I don't think flooding is the issue as the boat starts with or without the pump running while on the trailer as long as it was primed first. The first time i took Pagan out it only had the mechanical pump so it was a bitch to start because i couldn't get the carbs primed, when i did get it going apart from running rich (needle adjustment) it ran fine..no flameouts. At Yarrawonga i had dissconnected the mechanical pump and only had the electric running and again it would run on the trailer just not in the water.......is it possible that it's alergic to water??? Not a good trait for a race boat, guessing if thats the case it wasn't too successful. I WILL PERSEVERE

Ray, does it feel like its running out of fuel when it stops or does it just cut out .
How long will it run on the trailer with the prop shaft un bolted .
May be the mag is not well and loosing voltage after a short time .
Ross

Hey Ross, it will run on the trailer indefinately or at least it did, i havent tried it since Yarrawonga. Thats my next step. Since Yarra i have put copper leads (back) on because it didn't seem to have a lot of spark. I've been told that magies either run or not, is it possible that they can go off song? Could be that it dies under load ???

Frank do you have a photo of the other side of you engine, that looks doable (if thats a word)

Ray, have you tried running it on a separate fuel can , as there may be some thing in the fuel tank floating and blocking the pick up pipe as it sucks more .

Ray, have you checked fror a wasp nest in the tank? It can happen with these old skiffs that have been sitting around for a while.

Ray, 7 pound pressure is way to high for Carbs designed to run at atmospheric pressure only. It will always push past the needle assembly.
All other ideas are good , you need to be sure of the feeds from one end to the other.everything must be clear.

Is there any corrosion in the carb Jets or passages , it only takes a small amount of corrosion in main jets to lean the mixture and old fuel left in systems can cause this, fuel with Ethanol is even worse. Further , lean mixture leads to higher temp in combustion chamber and can cause the plugs to stop firing properly. When cooled a little engine runs again. If plugs have been "cooked" they must be replaced. When the plugs are in this state the engine is running strong then just cuts out.
Wildwoody1.