pete2222

Please can someone advise how much fuel should ideally be primed into the carb before starting a nitro engine.

I have a .28 buggy engine (Macstar) and am using a pull starter.

I want to get it to start regularly first or second pull, which I have managed on occasion.

I have experimented by blowing the fuel trough by attaching a 5ml syringe to the air line attached to the pipe. I have tried starting with 3, 2 nd 1 ml of fuel in the carb, but I now realise that I can start the engine quite well without pushing extra fuel into the carb, without the fuel pipe attached in fact, because of the fuel remaining in the engine after it's stopped (from pinching the line). I'm also worried I might have been locking the engine up a bit with too much fuel

Can someone please help and advise whats best for an efficient start.

Thanks

rcnitrohead

To prime, tug on the pullstart about 2-4 times to prime the engine[8D]

pete2222

Sorry, I was hoping for a bit more detail/accuracy. Do you mean, pull it 2-4 times with finger on pipe end, after the fuel has reached the carb?

DaveG55

The fuel should just reach the carb. You should not have to force fuel into the carb. After that the engine will pull it into the carb and, if it's tuned right, it will start on the first or second pull. If you have to continue to pull and pull - like past 4 or 5 pulls - then you have a tuning or fuel delevery issue. Once warm the engine should start easily on 1 pull.

SManMTB

Just bump it on the box with the glow driver attached. No need to prime it really. Block the exhaust with your finger for a few blips and you're good to go.

DaveG55

That would probably work fine except he speciffically said he's using a pull start

SManMTB

Ooops.

Pull the pull start then instead.

RBMike

I think priming regularly (at least the first start of the day) will add life to your motor due to less wear at start-up. As for me, I pull the pressure line off the pipe & blow on it until I see fuel getting to the carb & I do it with the trottle open. That's all.

Anthoop

Hi firstly i will say that i have many cars and motors but recently i have aquired a new Hyper7 fitted with the MacStar.28...but that is by the by really as the info. Dave has supplied you with here
..is exactly what i would say...hold your finger on the end of the pipe...pull the pull start untill fuel just reaches carb,apply glow stick...should start on first or second pull...that's it.
If it does not start it could be a number of things-glow plug/plug battery/carb settings/fuel etc.
please let us know how you get on.

ozzie-crawl

some mite say not to do this as it mite wear the seal out a bit quicker but never found a problem myself i put my finger over the stinger and flick the fuel lid up once or twice and it pressurises the tank pushing the fuel staight up to the carbi and never had it flood the motor as u only need a small amount of fuel to start up

pete2222

Thanks for your replies. I recon I've been over-priming. I will try starting as soon as the fuel reaches the carb.

Using a syringe to blow the air though is better than blowing it with your mouth I think.

rcnitrohead

Whats the point though? That is so inconvenient and not to mention dumb looking carrying around a fuel filled syringe. I'm not trying to be an @$$, but we have been priming our engines like this for years and I've never heard or see anyone use a syringe..[&:]

j_blaze

great idea but you are putting a/or several pinholes on the exhaust line, may cause tuning problems or other stuff. before a starter box i used a fishtank 1 way valve and T joint. i had the fuel line connected with the cross section of the T and hooked up the 1 way valve on the leg of the T wit a short piece of fuel tubing to blow on. it works but a bit much. with the starter box all you do is plug the singer and push down on the car about 3 seconds, the hook up the plug and vroom, she's on.

pete2222

rcnitrohead


If we only did what we had seen or heared others doing there would be no progress and we would still be swinging from the trees in a jungle in Africa somewhere:

In the past, I have blown through the tubing to prime the engine, but the 5 ml syringe method is much better and worthwile for several reasons:

1. The 5ml stringe is really small and carrying this around is insignificant. It just sits alsongside all the other stuff (screwdriver, glow starter, spare plugs etc) that most bashers or racers carry in a box or whatever. In case you mis-understood, you don't put fuel in it, just empty air, which you squeeze through at the place you would blow.

2. The silicon next to the pipe invariably has dregs of oil and unburnt fuel in it. When you blow down it, these get on your lip and inside your mouth. In my case, this really stings and can be sore for a day or so after. Nitromethane and the other fuel additives are toxic, so your long term health is at risk if you do this. (As a scientist I have some insight into this).

3. As far as looking dumb goes.. what can look dumber to an "non-nitro head" onlooker than the sight of a middle aged man on his own in a park bending over a toy car blowing it through a tube!!! (and then frantically yanking away trying to start it). A 5ml syringe is far less dumb in comparison.

Are you convinced?

RBMike

I don't put the tube in my mouth, I make a circle with my finger around the end of the tube. I never get any on me (or in me). It has worked fine for me for 20+ years with no ill effect. I don't even know what nitro tastes like and I have one less thing to tote around. If you want to use your syringe, that's OK.

lsurber

I would agree with DaveG55 about pulling the starter just enough to get fuel to the carb. At that point the engine should fire within 2 pulls. If it does not and you need to prime more you are most certainly running lsn too lean! If the engine get fluid locked then you are too rich!

It should never be difficult to start your engine if it is properly tuned!

pete2222

I pulled the pull start about 20 times and still couldn't start it. It was about 10 C outside.

I then heated the engine with a fan heater for a couple of minutes and it started frist pull.

Do you think this could be because the engine is very tight. It's quite new (its had 5 Litres through it)?

DaveG55

Yes
Many engines are hard to start until they are run for a gallon or so of fuel. Heating them with a hair dryer or a heat gun makes it much easier. Also, nitro engines are harder to start in colder temps. 10 C (50f) is not too, too low it is getting down to where these engines can be picky about starting. As the weather gets cplder be sure to richen the hsn a bit as cold air is denser and the engine will tend to run leaner on summer carb settings.