Roger Dyke

Charles: Thanks for your input. The carb "O" ring is new as it came with the new carb. I also push down on the carb when tightening the pinch screw. There is no problem with leaks or adjustments on the carb whatsoever. I have now got one of the engines (46) in bits as I am replacing the bearings (precautionary). When removing the backplate, the backplate seal looked perfect. I will know more when I have finished re-assembling it and tested it in a bench stand.

Thanks. I am aware of that, but it’s a good starting point before final alignment.

J D 8 - Moderator and Konrad, Thanks for your replies. It seems that I'm not alone then. When reassembling, I'll return it to the same place I found it between two of the head screws on the left looking from the back.

I was thinking something like that, but there is no mark on the top of the crankcase or any evidence that anything has ever been there.

Hi All, I have been watching john Kirkham on YouTube changing the bearings on an Irvine 53. On it he points out a tiny slot at the top of the piston liner which mates up with a little dowel in the top face of the crankcase. I am carrying out the same operation on my Irvine 46 mk3 (red one with 'made in England' cast in the side). My problem is, that I have the small slot at the top of the piston liner but no dowel at the top of the crankcase for it locate with. Is this normal on some engines?

Quoted from the BMFA handbook:- "and make sure that wherever available, a failsafe is set to prevent the aircraft flying away in the event of loss of signal"

By the way, my two red/maroon Irvine engines both have “Made in England” written into their casting.

Correction: Looking again at our club rules and also the BMFA rules, they both state that if your transmitter has a "failsafe" system available, then it should be used. The action being to "prevent the aircraft flying away in the event of loss of signal". Not to 'kill the throttle' as I stated in one of my previous posts. Thanks to you all for your very useful info.

Hi Martin, Thanks for that. I would have never have thought of that. I suppose it's a strip down and new bearings then. It seems such a shame as the engines run pefectly.

Cuban8: A question you asked earlier. Having now verified that there are no leaks on the carb "O" rings or joints, I've also tried your tip of putting my finger over the air intake with the barrel fully closed. --- No difference whatsoever, still continues to tick over at a couple of hundred RPM's for about a minute.

Cuban8 and PatMc, Many thanks for the tips. Our club rules say that we have to have a method of killing the throttle both in flight and on the ground, hence the question. I now have a few things to try at the next opportunity.

I’ll bear that one in mind as a last resort as the engines are a little tricky to remove. I haven’t seen any evidence of fuel leakage from the front bearings up to now.

As mentioned earlier, the two carbs are new and the 'O' rings look and feel perfect. I have removed one of the carbs and attatched a length of fuel pipe to it (main needle open three turns). I have opened the slow running needle a couple of turns and placed the carb under water. I then blew as hard as I could down the fuel tube with the barrel closed -- No tiny air bubbles whatsoever. There definitely doesn't seem to be any leaks. A bit of a puzzle this. Thanks for the link to Modelfixings.

The Jetstream carbs that I have do not have the throttle-stop screw as indicated. The slow running screw setting is ideally balanced for good transition pickup. The feed pipe to the carb is shielded by the fuselage side so is a little difficult to get to. Apologies for the negative answers as I'm sure I'm missing something here. I am going to remove the carb to do some leakage tests on it. It is a rule of the club that I'm in, that we have a means of remotely killing the engine (hence the original query).

Cuban8: I never thought of the obvious, putting my finger over the air intake. I'll try that and thanks for the tip. J D 8 -Moderator, Brian and Paul: Both carbs are genuine 'Irvine Jetstream' and new. Also at cut-off the the barrels are fully closed against the spiral end stop. As far as I can see (with a small torch) there is no sign of a gap between the barrol hole and the body. The problem must be staring me in the face as I have been running glow engines for years and never had this problem before.

Hi All, I have two Irvine engines. A red 61 mk2 and a red 46 mk3. Both engines in their models work really well. My problem is cut-off. From tick-over at about 2500 RPM or so, I operate the cut-off switch and the revs immediately drop to probably a couple of hundred RPM and stay that way for about a minute before stopping altogether. Both engines are the same. I have checked the carb barrels and they are completely closed. The carbs are new so it's not wear. Any ideas? Roger

Thanks for that, I'll give it a try. My question really was, which way around is the default supplied position as the previous owner has probably moved it.

Hi all, I have just purchased a second hand Irvine 46 mk3 (red one). It's silencer is stamped "1E". Inside the silencer is a cone baffle with a hole at the pointed end. The cone is trapped between the two silencer halves. In parting the two halves, I found the cone with it's narrow end pointing towards the engine. Is this correct, as I was sort of thinking that the pointed end of the cone should be facing the outlet to the rear?

I have just removed an OS 40FP from a model (unscheduled arrival.....). I remember purchasing it new back in the 90's. 100% reliable engine. Best engine ever.

Thanks Manish. Taken on board and noted.

My thanks to you all for your wonderful and comprehensive replies. You have certainly give me a lot to go at when I'm next down at the field.

John and GG: Thanks for your input. Martin: Yes, it does have flight modes. I hadn't really looked at that. I don't really want to make it complicated. I like to keep it simple being old school. Nick: I missed that. I'll have another look. Thanks for that. Chris: Thanks for your thoughts.

I don't think my Spektrum DX6 G3 has got the servo slow facility. Shame as that could have been useful. I think that I am having to re-think my idling and throttling as what I am after is probably not possible (ideal world).

I do run 5% nitro (newish fuel) and aircraft balance is good. Yes, a minute is a long time for a glow engine isn't it. I hadn't really considered the cooling down making that much difference but you may be right. With the slow idle I'm probably trying to over-egg the pudding, as they say. Thanks for that.

Thank all for the info. I usually aim for about a minute or so idling time, but no matter how I fine tune the slow needle, I always have to be careful how fast I increase the throttle for the revs to pick up after that time. Otherwises it's touch and go whether they suddenly quit. From what you say, It sounds quite normal. By the way, the two engines in question are a Super Custom 61A with a new carb and a Irvine 61 Mk2 (red one). Both are in very good condition with good compression. The props are 13x6 APC.