Engine Doctor

An update on the CRRC 45cc engine.Fitted in a 84 inch Eurobat . The  outing before last I put the model into a steep climb ,the motor sounded very laboured for a couple of seconds then stopped ! Landed it safely and noticed some oil on the c/case. Later stripped engine down as it had no crankase compression and so couldn't draw any fuel. At first I thought the front oil seal had blown but late found it had sucked in the cylinder base gasket . The remains of the gasket were still in place but had turned all sticky  , soft and horrible . I made a new gasket and fitted it and all is normal again . They may be cheap but they are powerful easy to start and keep on going.

Hi Ralph . thers not a lot of things to go wrong in a two stroke engine .Is the compression OK? if so suspect the bottom end or crank case compression. Crank case compession is more inportant than cylinder compression on a two stroke engine. after 50 gallons of fuel i would suspect some wear may have occurred on the bearings. Does the engine sond quiet and smooth ? or does it rattle ? When did you last change the glow plug ? These deteriarate after prolonged use . if the top end (piston liner) are ok a set of bearings will set you back about £15 and are not difficult to fit . A bit cheaper than a replacement. Hope you get it sorted . E.D

Hi Gary . They do still occur , though it seems not as frequently as they did a few years ago. I have just put details of our clubs annual table Top sale/Swapmeet in the events part of this Forum. Probably a bit far for you to travell though . Hope your enjoying the hobby again. Regards E.D.

Medway Model Flying Club annual Tabletop sale / Swapmeet MMFC are having their annual swap meet on Sunday 9th November at Iwade Village Hall. Iwade is just north of Sittingbourne off the A249,situated in North Kent .You can sell , swap or buy anything to do with model aircraft ,boats , cars, trains etc. Tables cost £7.50 in advance or £8.50 on the day, to include entrance for two. Entrance costs  £1.50 .  Sale starts at 10 am, Stall holders from 9am All proceeds go to the Kent Air Ambulance...For further details or to book a table contact Colin on 01634 317187 / [email protected]   or Phil on 01795 476535  /   /forum/smilies/tongue_out_smiley.gif[/img][email protected]][email protected]  Thanks. 

Hi Neal I run a 45cc crrc (the earlier version ) in a 80 something inch Eurobat and it runs and pulls superbly . Flown about 3hrs and gets better every flight. The ignition system supplied interfered badly with the radio so I replaced it with a Westons runtronic unit . Its now excellent and starts easily. I dont know how long it will last as it has some serios rock in the crank bearings although the newer version has been completly re-designed .I have recently fitted and flown a DL 50 in my sons Vision . That started second flick and also runs superbly .No problems with the ignition unit supplied. Had to have a couple of tanks through it on the ground then the compression really built up and the general feel of the motor became much smoother. It is a  very powerful engine . Parts are easily available and not to expensive ,through the uk distributors . Cost around £240 in the uk inc postage My other petrol units are a McKay 30cc , thats a great engine very powerful ,light and easy to set up .Its more expensive but is built specifically for the model market . My last petrol engine is a  Zenoah 45 which I bought second hand .Beware of second hand units that have built up cranks if you dont know or trust their history or if there is any evidence of a sudden landing /crashes! It was fully cowled  in a model and felt fine but when the cowl was removed some broken fins were evidence of a crash The Zenoah 's crank was twisted out of alignment and it had been assembled previously by someone who obvoisly didnt under stand how to use shims to adjust end play . Its been rebuilt now and seems to run ok  !  ll . My son recently paid nearly £500 for a 3w 55i .It was heavy and cumbersome  although the quality was superb , you still had to supply your own mounting and muffler . It was replaced with the DL50 ,much lighter and smaller , this was supplied complete with a muffler (although to be fair this does need some more baffles as it is quite noisy) and a mounting system .All for under half the price of the 3W, good value ? The Cheap engines seem OK but only time will tell . E.D

Hi . What mark of 120 pumper do you have? the Mk 11 and Mk111 both require different plumbing. The Mk 11 has the pump , a mechanical gear type of pump, mounted on the back plate .It is fitted with three fuel nipples .Fuel in (from tank) fuel out (from pump to carb ) And fuel return (this is for excess fuel to return to tank.)Make sure this is not kinked or restricted . I usually fit a slightly larger diameter fuel pipe to this as any restrictions can cause the motor to throw a prop, not very nice ! The mk 111 just has the one fuel pipe nipple and no fuel return pipe ,  The pump is a diaphragm type and is integral with the carb it  has a short pipe conecting it to the crank case for Crank case pressure to operate the pump. No exhaust pressure is required with either type . Plumb your tank as normal for clunk and fuel fill/empty pipes . Both types MUST have a fuel tank breather to allow air into the tank as fuel is pumped out . Failure to fit this breather will cause the engine to cut out after a short run. Both engines are superb and once set up require little or no messing. DONT be tempted to strip the pumps down unless your are confident and up to it as the earlier pump has a pressure release adjuster screw , once messed with it will take ages to sort unless you really know your engines. The beuty of these pumps is that you can fit your fuel tank further back over the Cof G so that you get a constant trimm setting unaffected by the weight of the fuel. Hope it helps E.D

Hi Craig . If your not sure about converting your car engines why not just sell them on e-bay and buy new . Model aero engines are cheaper than ever at the moment. Buy  ASP , SC or any of the budget motors and you will be ok .If you can afford it buy a good quality motor such as OS . Dont be tempted to buy any MDS engines on offer as these , will in all probability ,give you problems. Galaxy Models were recently selling  SC 46 for £39.99 . To convert your car engines will involve removing the pull start /backplate assembly  and modifying or fitting a different crank shaft then fitting a normal back plate. then you will need a prop driver etc . The cylinder head , if its a large heat sink type ,will probably need changing although not critical provide it can fit in the model . The cost and or agro of finding all of these bits probably wont be worth it . Also you didn't say wether you were learning to fly ? If you are then 20 size models are not as stable as larger trainers (46 size) so you would be at a dissadvantage anyway. Regards E.D

Hello Howard , I dont know what happened with my last posting but it seems to have deleted some of it ? I t should read Try filling a sqeezy bottle with clean fuel and put some fuel tubing on the nozzle and insert this through the plug thread /hole .............etc . E.D

Hello Howard , Does the motor feel ok ? as bearings breaking up will leave the engine feeling gritty and ntochy.  If its ok it may be that the first plug that blew let a bit of the element fall into the cylinder ;  insert through the  plug hole with the engine inverted and flsh out the combustion chamber . Catch the fuel that comes out in a clean container and allow to settle to see if any particles are washed out . Any metalic bits should be investigated . Failing that its a strip down to see whats going on . Hope it helps . E.D

Yes please . It would make an excellent prize for club raffle in aid of the Kent Air Ambulance. thank you in anticipation .  Phil Fearn

Hi John . As your club mates say , the small amount of back and forth play and small leakage is nothing to worry about and is perfectly normal on these plain bearing engines. When the plain /main bearing finally wears beyond its usable tolerance you may notice that fuel actually spits out whilst the engine is running ; this will also coincide with a fall off in performance . The use of good fuel and properly balanced props will keep your motor running for  years. I have just retired an OS 35 FP from my club trainer ,used to buddy newcomers. Its been flying that model for about five years and was still running fine ,just wanted a bit more power. A quick check to see if the main bearing is ok  is to hold the prop in line with the cylinder and test for movement back and forth on the prop tips . This should be done when the motor has just been run as thick oil will mask the play. Any noticable play will be detected . Only worry about this play though when the performace drops off. Black oil can appear at the front of the main bearing if the thin steel thrust washer has been lost/removed when the prop driver has been removed. Thjis allows alloy to rub on alloy and a resulting black mess will be created (aluminium particlesin oil) Regards E.D

Hi Richard . I have a black horse ( or is it a seagull ) artf ultimate . I bought it at the swapmeet at last years Hop farm show.I had a SC 120 lying idle so fitted it and Its a perfect match. Flys superb with plenty of vertical.etc. Obviously cant prop hang like the guy with the Brison 52cc motor but is a great flyer . The other good thing about it is that it fits in the car all assembled so no fiddling about at the field.

Hi Ben .All fourstrokes try to back fire when primed and flicked like a two stroke.  First of all discard your plastic spinner ( never use plastic on a f/stroke ) and fit an ally spinner. You will have to addapt the the spinner adaptor nut to a lock-nut to enable the cap screw ,that pulls the spinner cone onto its back plate to be fitted . Starting a fourstroke is slightly different to a two stroke . First prime the engine until nice and wet . Dont connect your glow start yet . now flick the motor over as usual to make sure its not locked with fuel . When happy that it spins ok connect the glow. Now use a chiken stick ,or as I do and flick the motor backwards agianst compression using the spinner the motor will (should ) backfire and spin in the correct direction and usually carry on running. If you wish  to use a starter motor then prime the motor flick over WITOUT the glow connected to ensure it isn't locked now still without the glowconnected spinit over with the stater for a couple of seconds  to empty out excessive fuel . now connect the glow and sin with starter again . you should get an instant start. Once a four stroke is warm then a starter will get it going without all the priming etc . All the forgoing  assumes that the fuel mixture has been set up .  Good luck and let us know how you get on E.D.

Hi Be very wary if you use WD40 for freeing up gummed engines. I have experienced enines firing when flicked over with wd 40 in them and it can be very painful .Beware. E.D

Hi Shaun The slow running mixture screw is the screw at the front of the carb and screws in and out horizontaly.It adjust the slow running mixture by either restricting or allowing more air into the carb when the throttle is closed. If you look in the slow running air intake you will see the end ofthe slow running mixture screw .turn it until it about half way across the hole.The throttle stop screw screws into the top of the carb . turn this screw until the carb  can be completely closed  (no air gap) . Open the throttle enough to start the engine with the throttle trim on your TX and start your engine . Adjust the fuel mixture for correct running at full throttle . When you ar happy with the full throttle setting close the throttle and alow to idle for a few seconds. now open the throttle fully . If your engine coughs and splutters and speeds up slowly it is too rich and the slow running mixture screw needs  turning out . Only make small adjustments ,say 1/8th of a turn  and retry. If you open the throttle and the motor dies and hunts for fuel then the idle mixture needs richening (srewing in) Adjust until you get a reliable idle and good pick up.Hope this helps . E.D

Hi Steve . Do keep a plug socket set up as you may have to remove the unit from the model for service /repairs etc. To make sure that the plug doesn't come un-done during flight try putting a 1/2 knot in the leads before plugging them together then any strain on them will pull them together .Only use a 4.8 volt (4 cell ) battery for the ignition ; a 1300 mAh will last you all day . The newer Crrc Pro engines are good value for money and very powerful. I am still running an early 45cc motor and it just gets better and better . It pulls a 80 somthing inch Eurobat vertical and is very reliable. Good luck. E.D

I never win anthing ,but that has change sometime ! Bring it on

Hi John .When you say a beginners kit ,do you mean begginer as in flying or building ? If its flying you probably know that a Spitfire is not a googd idea ;if its  building then a spitfire may not be a good idea to start on but try a simpler scale project .If it really must be a Spitfire then try the BMFA classifieds or the classifieds on this RCME site with a wanted add. You didn't memtion how big you wanted to build ? Balsa craft (now extinct)did a spitfire kit about 40 odd inch ,if you can find one. Pilot (also extinct)did a proper builders kit,again about 48 inch, a few years ago but you will probably have to pay a good price for one of those ,quite rare now. Apart from Plans the only "proper kit" I'm aware of thats easily available is the DB Spitfire  for 30cc plus engines. The Top fFight Gold edition kits may include a Spitfire they were about 65 inch span ,but not sure. DONT be tempted to buy a PICA  kit , unless its  a really early one . They were laterly produced in italy and the materials and, well every-thing about the kits are IMHO awful/rubbish. I am half way through a DB Hurricane build for a mate. although the plan shows a Super Tiger 3000/3250  I am fitting a 50cc petrol for reliability . The DB kit is pretty good with the built up wing kit . Prior to that I built a P40 Warhawk from a Pica kit and it was hard work with all the rubbish parts having to be re-made from proper materials. Hope you have luck in finding a project but chat to your club mates before jumping in. Regards E.D>

Got a lovely YS waiting for it . Yes please !

Yep use the fishing trace ( as above ) and plastic tubes (snake leftovers) then thers no chaffing or wear. 2.4 shouldn't be affected by metal to metal noise but range check it anyway with the engine running. Good luck

Hi Kevin .If you use a small vent to the tank( Air will pass through a very small opening ) the tank will be able to breath and due to the fuel being drawn by the engine ,fuel will not come out of the breather.I have in the past put a building pin in the end of a piece of metal fuel tube then squeezed in the tube around it , when the pin is removed  it leaves an ample hole for air to enter and no fuel (or very little )will come out of it. I fit this pipe to the fuslage and connect with normal fuel tubing to the tank . Dont forget you dont need a pressure pipe to the exhaust on a pumped motor. Regards E.D

Hi Dave . No I never had one in the first place. Have you tried an add on the BMFA classifieds ? or here on this forum . There are a lot of very friendly helpful modellers out there who have helped me in the past. The other options are Steve web or try a Google search for Enya engines . I know theres a great site for OS engines with exploded views and spares list etc ; possibly the same for Enya.  Most manual s / info sheets seem to contain the same information re safety, running in ,oil content of fuel and so on. Unless you want one for collecting reasons or for an exploded view then almost any  of the current info sheets will give the requied info Re the tube from the crank case ; try to keep it as short as possible to exit the cowling or use a short lenght to fit the nipple then fit a larger diameter tube so that it can drain during running. Regards E.D

HelloEric  Yes that  green veridgris stuff is the result  of the  the copper being is being dissolved/attacked . You probably noticed that the coper was also turning black. A simmilar reaction occurs with the brass tubing but as their is only a small ammount of copper in the brass the tubing is degraded and becomes brittle and porous quicker as only the zinc is left . Perhaps someone on here is a chemistry wizz and can give us en explanation ? Since I have started using the aluminium tubing i havent had any problems. Regards E.D

Hi Dustin . I regularly use a three line set up . The main differenc to the set up mentioned above is that I only set the pressure pipe from the exhaust to the top of the tank ; the other i set into a bottom corner of the tank (or the center bottom on a round tank) I usually fit a short lenght of fuel tubing to the end to stop it rubbing on the tank. This allows you to fill and empty your tank from the same pipe by simply tipping the model to the side that the tube is set to , almost every drop of fuel can be drained. Fitting a fueling valve into the fuel supply tube should be avoided. They have been known to vibrate and allow air in causing unreliable engine runs , not good.  I also use either a ripmax or a Dubro sintered metal filter clunk . Thes clunk/filters ,super filter the fuel and allow every drop to be drawn into the fuel line ,similar to the felt filters used in petrol engines.Fuel left in the tank ,even small amounts can make its way to the engine and cause corrosion in bearing ,efectively ruinning your engine. One last thing ,when putting your tank together throw away the brass tubing supplied and replace it with aluminium tubing . The modern brass tubing supplied with tanks will rot very quickly if you use nitro in your fuel, as the nitro methane attacks the copper content in the brass leaving pitted and split brittle tube s that allow air leaks. . Hoppe it helps good luck . E.D

Hi LHR Dave . I had problems with a an Enya 60  4stroke some years ago . It was a pig to run and kept on throwing the prop. I tried all makes of F/S plugs and  eventually I fitted a taylor short reach ,idle bar ,plug( this helps reduce the compression ) .Fuel was sythetic  oil with 10% nitro. This made the motor very easy to use and it ran  and idled faultlessly from then on. I still have the engine but rarely use it now  as its comparatively heavy and not suitable for the type of models i'm flying. Spares are still available I believe from Steve Webb. They have spares for Enya engines from way back  and the service is excellent. Good Luck E.D