Come on Gusty, would have missed this (at least warn me in advance  ) - AVATAR, of course!

Aerovishwa - you fell for it! Sherlock Holmes NEVER EVER uttered these words, "Elementary, my dear Watson", in any of his adventures / stories. 

may be i did...!  but i  recall the quotes in the  book...!

just some more info....

After Heavy research on this Engine have been able to master the system by striping open both the Carb as well as the fuel pump system. The functioning of the engine's Carb and pump is same as a walbro carb. only the fuel pumping stage and the HS LS needle and venturi has been separated. After a lot of permutation combination have been able to run it smooth with both with Fuel pump system as well as without fuel pump system using exhaust pressure fuel tank method.

Firstly Unlike a glow HS needle this has a blunt HS needle which is by design required to be completely out of the fuel vent after Half throttle open. At full open Throttle you need to have a clear gap between them of 1-1.8 mm. please refer manual posted below. This is very essential for smooth transition from Low RPM to High RPM. This is likely to disturbed when you tamper with the Low speed setting at the HS needle side.

Unlike what it has been shown in the manual it was supplied with, the low speed setting is inside the throttle arm. not on the side of HS needle. The screw on the HS needle side is moving the fuel vent fwd and back, however it is set in place by OEM with thread lock. please do not disturb this as this is likely to affect the full open gap between the vent and the needle i.e. 1-1.8 mm.Adjust LS setting only from the throttle arm side. you should not be required to disturb it more than a turn.

Please refer second page of manual here http://www.himodel.com/manual/GT9_Installation_and_running-2.pdf Idle throttle open position is 1/3.

Oil to Fuel ratio is 4-5% never run below 4% of Oil i.e. 40 ml of High grade synthetic 2T preferably to a litre of Gas.

After full throttle when closing, at idle it is ok to be slightly rich initially but it leans out eventually within few seconds. It is because of the way the pump is designed with diaphragm and plunger to cut supply on closing.

However if it is perpetually rich at idle. the pump supply is more. which can be set by adjusting the spring tension inside the four screw side of the pump. if it is constantly flooding at high as well a low speeds and steady throttle response at less than one turn of the HS needle then there is foreign particle inside the plunger and not allowing the pump to cut supply at throttle close. It is advisable to use a fine grade fuel filter before the pump to prevent this.

By opening the four screw side of the fuel pump by bending the rocker arm up by fractions of mm you increase supply and by bending it down you decrease supply.

Zonuna Should try bending the rocker arm up in the pump then Full RPM will be in just 1.5 turns of HS needle and steady idle at 1/3 open.

Checks to test the pump functioning.

(a)   You should be able draw air through the outlet side i.e. nipple connected to carb.
(b)   However you should not be able to neither blow air now draw air through the inlet side which is connected to the fuel tank.
(c)   Pulse pressure side connected to crank you should be able to feel the diaphragm move up down when blown and suck air.

Faults

(a)   If you able to blow through the inlet side then there is foreign particle inside plunger please clean it as it will flood engine.
(b)   If you are able to draw air but only with heavy resistance in the outlet then the rocker arm is far too low and needs to be pulled up by half mm as your engine will require you to open HS more than 2 Turn to reach full RPM however will cut rich on close.
(c)   Air mixing in the outlet fuel. leaking Diaphragm/Fuel line touching the engine/exaust. All screws need to be tightened to get good seal. Puncture no rectification. Fuel lines should not touch hot engine parts.
(d)   Inspite of having gap of 1-1.8mm between HS needle blunt end and the fuel vent in the Air inlet, Carb largely dependent on the suction at air vent for fuel supply (symtoms are when you are not able to open the throttle full to reach full RPM at any setting) then there is not pumping action in the pump section. Faults are
       (i)   loose pressure pipe line at the crank.
       (ii)  Deformed rubber valves at the pump.
       Remedies
       For (i) above found normal glow fuel line the best for use at Pulse pressure pipe line. always use metal wire locks at the    
       crank. The heat tends to soften other lines and making the seal in effective.

       For (ii) above some times due to prolonged disuse the Rubber flap valves in the pump section gets deformed or gets stuck with
       the sealing surface with no pumping action. Open the one screw side of the pump and check the flaps valves are free to move
       and are flat and makes good seal with the flat surface.

       Checks : with the four screw side open One screw side sealed when you lightly press the rocker arm you
       should be able to blow through the inlet nipple side and should not be able to draw air at all.

Running the engine on gravity feed by keeping the air vent fuel tank higher than the engine is another method which can be used for running in and bench test though cannot be used on a model for obvious reasons.

One other method of running the engine is by exhaust pressure line pressurizing the fuel tank. Though the mounting holes of the exhaust for a glow engine and this engine are identical and their exhaust are identical I recommend not using the glow exhaust since Exhaust pressure of a glow engine is much much more than what is required for the viscosity of Gas fuel. The engine runs too rich and HS needle has to be closed to just about 1/4 turn to get the required fuel and the engine runs much much hotter due to exhaust pressure.

I had drilled a 2.5 mm hole on the provided exhaust threaded it and fitted it with a standard nipple. put a glow fuel line as the pressure pipe line from the exhaust to fuel tank, as I found it to be the best performer under heat.

The standard nipple on the provide exhaust was found to work well but there is no means to control the pressure to the fuel tank in this method and the residual pressure on the throttle close always tends to flood on sudden throttle close. Only means to control fuel was HS needle. which attained good setting at 1 turns open.

I replaced the standard nipple with the nipple of four way air retract distributor with inner dia of 2mm and replaced to standard glow fuel line to a 2.5mm inner dia glow line. Now the engine was performing well at 1.5 turns of HS needle steady Idle as well as peak RPM at full throttle open.

I would not still recommend it for a model use before I myself testing it on a flying model and for two reasons below.

(a)    Black residue oil tends to flow through the line to fuel tank though in very minute quantity, some times tends to block air flow initially till such time it clears (Same aggravated more due to use of smaller inner dia pressure line). The same when it reaches fuel tank will contaminate the quality of fuel though it should not matter much since you are using small replaceable quantity.

(b)    Initial priming become very difficult since the crank nipple is now open and fuel is not sucked in when you flip with thumb on the air inlet. Now you need to blow the pressure line for initial feed. To get around this problem I had to put a screw with copper washer in place of the crank nipple to get initial priming which worked well (Please use a very very short screw not more than 3.5mm long as it touches the cam inside) , however cannot comment on the long term effect on the engine by the screw.

Use of standard nipple as well as smaller one is good for pressure feed. However I will reserve my recommendation till a model real flight test.

Great detail  , Like you mentions, the manual said the LS needle is on the HS needle side, That`s where we go wrong. We tampered the setting thinking that it is the LS needle (The manual said).
Is there any way I can back to default settings again. ?

Hi Zonuna to get back to original settings follow these steps

(a) Unscrew the (Manual indicated) LS needle at the HS needle side fully anticlockwise till it stops at end.

(b) Now the throttle arm will not move smoothly in some case. Screw back in about half to one turn clockwise the same (Manual indicated) LS needle. This will make the throttle move smoothly.

(c) Now tighten clockwise completely correct LS Needle inside the throttle arm keeping the throttle fully open..

(d) Now Keeping the throttle open, screw out the LS Needle anticlockwise out of throttle arm, till such time the gap between the blunt end of the LS needle and the fuel vent tip is 1-1.8mm. No means to measure this but visual approximation only.

(e) Now open the HS needle 1.5 turns start the engine and get the Low steady RPM at 1/3 throttle open. Say about 2000-2500 by adjusting the LS Needle. Keep it rich in idle RPM. Dont lean it out too much in idle RPM based on engine response while opening throttle you can lean it marginally.

(f) Now Open throttle full and adjust the throttle for good Peak high speed RPM which might vary based on the Prop you have used. Get HS Needle back 1/4 turn rich and you are good to go.

Thank you, I will try it out and let you know, If still doesn`t  work, will bring it on at Shillong fest for you to check.

Yes Sure

here is this engine being sold at hobbyking, similar pricepoint to that of rcdhamaka less worry buying from rcd

ngh engine

This engine is certainly not a plug and play.
There are a number of issues with the fuel pump and carb. I have gone thgrough 64 pages( over 1000 posts) in RC universe/groups on this topic. A lot of people have had problems.
I for one managed to get it to run on petrol for about 5 minutes. And i have spent another 10 hours tinkering on it and 25 hours researching.
Finally, i closed the crankcase vent line and put in a glow carb and glow plug and the engine runs well on glow fuel.
May be we only hear about people who have problems, but we do hear about a lot of problems.
And it takes some major tinkering to make the thing work. The fuel pump is not identical in all engines.
The connection to the tank and carb are located differently on differnet fuel pumps. In my carb the opening into which the HS Needle goes is drilled off centre, so the HSN does not close the opening properly.
Maybe it will work with muffler pressure and a glow carb as well.
JUST ENGINES UK does not carry this engine, though they have the other bigger NGH ENGINES. I know they test the engines they sell and offer good support, so maybe this engine did not measure up. (of course, the engines they stock should not determine what we buy)

So be careful before you buy this engine. If it works well, then you are fortunate. If it doesn't, buy a glow carb and fix a glow plug and, fly it on glow (after paying double the price for the engine)

I received mine from Hobbyking last week, expecting problems, got them.
Put the said engine on a testbed with tank and electrical gear etc.  Filled up with 20 to 1, 91 octane petrol and 2 stroke oil.
Had the boys at the club check to se if I had connected everything up OK.
Would'nt start.  Checked fuel and that seemed OK.  Checked spark and that was good.  Tried adjusting all settings and still no go so decided to continue trouble shooting at home and got on with some serious flying.
  I took out the spark plug and reconnected it to the plug lead and took note of when it sparked and whearabouts the piston was at the same time by looking into the plug hole. It was sparking when the piston was at the bottom of its stroke.  I took off the prop and removed the hub which housed the small magnet and rotated it 180deg.  There are only 2 positions for it to go. Reconnected the plug and lead and got the motor to fire.  However so far I've only got it to run for 10 seconds by putting a few drops of fuel into the air intake and applying the starter. I'll keep fiddling and report back.  Meanwhile I'm open to sugestions as to "what next from here"?  Lazza.

i have serious doubt with these ngh junk.. do they even work? i havent seen even 1 working  ..  check out the jc evo engines.. they kicking dle's @ss .. and they are cheaper than hyped dle's.. dont buy engines from HK.. (they dont come with serial no. engraved on them.. )

Unlike most of the days yesterday It was running inconsistent at Full RPM however the engine died mid flight only once When I was doing a vertical unlimited. Luckily I had gained sufficient vertical height by that time to recover and land safely in dead stick. When it did not start for the third takeoff was when I realized the Fuel line to pump pressure was leaking and had given away totally by then.

The engine was stripped yesterday to replace the connecting rod which had also developed play during one of over size prop test runs some time an year back. The engine has once again become tight because of new position of the piston rings I have to break in the engine again now.  ( Yes was surprised to note this Engine has piston rings unlike all glow engines. I wonder what effect in long term for all those guys planing to use this engine on glow fuel by replacing the sparkplug with glowplug)

That is not good to hear. I am sure you would not put a massively oversize prop, and thus would feel this indicates poor material/heat treatment quality

No Sanjay Sir, Play happened an year back when I tried this engine with 12x8 prop and 13.5x4 Prop. It ran well with reduction in RPM but it was only when I changed the Exhaust also with the same props from the provided dustbin type to the muffled Glow Exhaust which had a smaller exhaust opening too in respect to the Dustbin type exhaust to try exhaust pressure line method without the pump, the damage was done in few mins. The engine ran too hot and I had to cut in just few mins but by that time the damage was done. I could always feel the play in the connecting rod while flicking prop from then on. I did not want to disturb it for long as the engine was running just fine. Only it was bit more click Noisy. I had bought the replacement connecting rod and kept it just in case it failed.

Only after the recent tuning in and Break in running for two hours in multiple sets of Nithin's NGH 9CC engine the sound difference became more apparent. His engine came with a very small volume exhaust and it was really loud bursting sound in compared to mine which is more muffled and so the clicking sound also was more apparent.

I was using a modified mounting bracket for the Fuel pump, which had broken yesterday and pump came loose and creating a loose pressure line. Since I was opening every thing to fit the pump and fuel line again, the urge to replace the connecting rod got the better of me. 

Aaah! That explains a lot. Especially constriction of exhaust, with associated heating.

A glow engine has a higher operating temperature, runs at higher RPM (higher calorific value) and a higher BMEP. I feel you will be running the engine under conditions it was not designed for.

Further unlike an ABC or a tapered sleeve and piston of an Glow engine this engine has a piston with oil scrapping rings and does not form a locking compression and kick back like a Glow engine in TDC. Definitely not designed for a glow operation.

I found odd that the piston connecting rod pin does not have a locking clip to prevent it from moving out of the piston therefore the piston pin had in fact carved a vertical trace of marking groove on the outer sleeve of the piston. Though this groove was well below the compression area of TDC, but must surely be adding to the friction of moving parts and reducing efficiency.

On smaller engines the gudgeon pin does not normally have a lock. Maybe there is another problem - the play in the crankshaft bearing is excessive?

My opinion was based on an 0.52 engine's connecting rod which i had replaced for Parambir some time back.

Sir It could also be due to the play which had developed in the connecting rod. Post change of connecting rod there is no play noticed.

Very nice touch down.. loved the idle at the end of the video!

Thanks Ashok.

Now the engine is running just fine, but not before I had to strip tne engine again to reset the piston rings correctly which i had done wrongly the first time.

The piston ring groove has a very small plunger pin which needs to be exactly at the split ends of the piston ring since the rings have a notch to accomodate the plunger pin. This plunger pin had come under the piston rings making rings very tight  and  I was thinking  it was because of new connecting rod. The plunger is a small pin of 1/2 mm dia and 3mm long in a hole which I believe has a spring inside.  could hardly see it with naked eye for the first time.

Now after correct fit now engine is turning smooth and running just fine.

I think you are the only one who successfully flown with this engine .........