Hi. Has anyone built the open crank hit & miss half scale Economy Engine by Engineers Emporium? I have recently completed one but cannot get it to start. All the usual checks have been made and all seems in order.
The suspect is the fuel system. I can draw some petrol from the tank by closing the choke and opening the throttle (as per instructions) but there is always air in the fuel line and it is not always reaching the carb. I have checked the fuel line and non-return valve in the tank and can see no obvious fault but, even after turning the engine over many times there is no sign of fuel on the spark plug when that is removed. I have even tried a lighter spring on the auto inlet valve but to no avail.
It seems to me that if there is no obvious fuel reaching the cylinder it's no wonder it doesn't start - but why? When I calm down a bit (!) I will try squirting a little petrol in the cylinder through the plug hole to see if there is any response.
Not the same engine but on my H&M I tried for several hours to get it to fire without much luck. Eventually got it to fire by chocking the engine, I did this by holding a finger over the air inlet so 75% was covered then flicked the flywheel over and it fired. I assume this increased the air velocity over the needle and helped it to suck in the fuel/air mix.
What fuel are you using, a lot of the engines in the US use camping stove fuel with WD40 added. You could also try squirting a bit of WD40 into the carb while flicking the engine over.
No experience with your engine, but. Try a small squirt of the diesel engine starter. I have a can in my shop branded "Start Ya Bastard"*. An engine of doubtful lineage takes the hint all other things being well. *This may be somewhat indelicate but it is the name of the product, I have no affiliation with the product, not even by birth.
Sounds like the stuff called 'Easy start' available here in the UK. Has been known to bring back many a cream crackered engine back from the dead. By the smell of it it's just ether in an aerosol can (not that I go around sniffing such things )
As others have said if the engine will run on "Easy Start" you know you have some sort of fuel or compression problem.
It is Ether so much more volatile than petrol. (Jolly useful for starting Diesel engines at -40 Centigrade but I digress...)
Have you broken in the engine? Vince Gingery mentions driving the Atkinson Differential engine with a electric motor for several hours to bed in the rings. A bit of light oil down the bores helps this. Initially this is done with the fuel supply and spark plug disconnected. He then suggests following up with some motor assisted running....
If the rings are not bedded in there will not be enough suction to pull through the fuel.
I'd suggest raising up the fuel tank so it is above the carb to see if that helps.
You do have a breather pipe on the fuel tank to let air in don't you?
Valve sealing can also be an issue with the tiny valves we use. Do you have a compression tester? Might be possible to make up an adapter.
From what I hear getting the carburation right on small IC engines takes some experimentation so don't be disheartened...
Once again I am so impressed and grateful to everyone for being so helpful. I know of Easy Start and the like so will try that together with the other types of fuel suggested.
I think Bryan may have the longer term answer because the engine is brand new and has never run at all so it seems reasonable that if the rings arn't bedded in there may be insufficient suction to open the auto inlet valve, this is the impression I am getting. Should one be able to see the movement on such an inlet valve I wonder?
I was quite careful when grinding in the valves but will try to do a compression test. I have checked that the tank breather hole in the filler cap is clear and have briefly tried a raised fuel tank but the petrol simply runs into the carb and floods it.
I do of course realise that getting a new engine running initially, especially by someone who has no real experience of such engines, is challenging so I will not become disspirited and will plod through all the helpful suggestions. So thanks very much to one and all.
On my engine I can see the inlet valve opening as the engine is turned over by hand, you do need a very weak spring, really just enough to return the valve to the closed position.
A lot of the H&M builds I have looked at run in the engine for an hour or so by driving them off a lathe or similar. The amount of time I spent trying to flick mine over probably had a similar effect it certainly wore a couple of blisters on my fingers
OK thanks Jason. I assumed the inlet valve spring needed to be weak and have used the one supplied by Engineers Emporium. I did briefly try a lighter one but still with no success but I will try that again if required. Glad to hear that you should expect to see some movement by eye on the inlet valve, I can use that as an indication of when the compression has risen enough which is where I am certain the problem lies.
I have rigged the engine up to my lathe with a flat belt and it is running in sweetly as we speak so that was a good tip. Like you I have suffered by constantly flicking the flywheel over. I have just got hold of a can of Easy Start so will try that after running in.
I am sure that with all this help and advice I will get the thing running eventually, in fact with what it's cost to build I had bloomin well better!!
Yes, that's it James. That one works OK and I have seen it myself at shows.
I am still battling on. I have confirmed compression OK and have chatted to EE on the phone. I was given some general hints so am still trying. I WILL get there - somehow.
Is the ignition timing very critical I wonder? It seems to fire with the timing advanced quite a lot in my view so I am experimenting there for a bit. I'm still not happy that sufficient fuel is arriving but it still won't cough with neat petrol in the plug hole or even Easy Start. Am concentrating on the mixture now.