skippydiesel

Ho Kiwi, Your twin engine manifold pressure/vacuum gauge is a great idea - wish I had one. I guess its likly to use two Bourden tubes to deliver the readings, so not so diffrent from my two gauge motorcycle carby balancer, just more compact.😈

Hi Rapture, "Our prop spacer arrived a couple of days ago." Aside from the obvious, moving the prop forward, what is the purpose/benefit of having a prop extension in this installation?😈

Hi Kyle, "The larger balance tube does give a better idle performance...... " Please quantify - what is "better" about the idle and what is operational advantage of this improvement over the OM design?😈

Hi Blueadventures, "I have the Synchromate and also a tube unit." Is this, a sort of answer to my "Do you follow, as per Rotax advice, your mechanical carby balance, with a pneumatic balance?" ie you have the gear, so am I to assume, you have used it? I Googled Synchromate carburettor balancer to try & get a handle on the equipment you may be using to do a pneumatic carby balance - nothing! Well not nothing, Google always gives something; Synchromate refers to a veterinary injectable medication containing the synthetic hormone cloprostenol, primarily used in livestock (cattle, horses, sheep) for reproductive management like synchronizing heat cycles, inducing ovulation, terminating pregnancies, or inducing labour. There is a more likly contender; TecMate SynchroMate (TS-101), for synchronizing carburetors or throttle bodies - is this it? There was also something called a SynchroKing, which may be similar to your TecMate - all pretty pricey. For what its worth; The Rotax Owners Forum technical advisors have opined, that the above type devises, are not as good as a simple vacuum gauge, for balancing carburettors.😈

One of the attractive features of this Forum, is the wonderful tangents the conversation can go to, without people getting all huffy about adhering to the origional topic. Sure it can be frustrating, if you are after targeted advice - most often a gentle reminder, will bring the responders back on topic.😈

Hi Blueadventures - Third attempt to get a bit more information The above statement, (now further back) mentions mechanical carby balance, what of the pneumatic balance??? Common Mate what's the big secret? Do you follow, as per Rotax advice, your mechanical carby balance, with a pneumatic balance? If not, why not?😈

I have used a pair of cheap (Asian made) twin carb motorcycle vacuum gauges, for about 15 years now. They are excellent! Come with a little adjustable valve for each tube, so that the needle pulse fliker/bounce, can be "removed". The "face"/ needle, can be zeroed if needs be. I had to purchase longer vacuum hose, so that I can have the gauges in the cockpit, while engine running. I always swop tubes, to assess consistence of reading - so far no discrepancy. Can't understand why people go and purchase expensive digital/electronic stuff ($500++?) when something like this is all the owner maintainer will need. ($21-$51) 😈

Hi BrendAn, I stand to be corrected; - Mercedes have never made a 190 car. They have made a series of 190 engines (190, 190E, 190D, etc). The 190 refers to 1.9L. The car, the engine is fitted to, wil be a W??? 190?😈

Hi Blueadventures - Second attempt to get a bit more information The above statement, (now a few back) mentions mechanical carby balance, what of the pneumatic balance???😈

The origional carby one will do me nicely. As I understand, the injected varient of the 912 has two advantageous over the same carburettor engine; Better fuel econamy Greater (total?) resistance to inlet ice. The disadvantages are significant; Much more expensive to purchase. Greater complexity - almost impossible for the average home mechanic to do anything with the fuel delivery throttle system. Potential to be very costly if goes wrong. Repeating what I have read- The 912is fuel savings; Could take the average owner/ pilot near 20 years to equal the greater purchase cost. Are possibly attractive to flight schools/hire operators (fast hour accumulation), assuming the sale of high time engine is attractive to 2nd hand purchasers. 😈

I had Nissan Skyline , bought 2nd hand, back in the early 1980's Not sure but think the engine was 2.4L. Car all Nissan, disk brakes, independent suspension & very nice to drive - engine looked to be almost an exact copy (less the star on the rocker box) of a Mercedes.😈

Hi Blueadventures - The above statement, mentions mechanical carby balance, what of the pneumatic balance???😈

Just like the Japanese indeed - they only improved a design, where they think its worthwhile to do so. A Big Balance tube serves no practical purpose, other than to lighten the wallet (this topic has been thoroughly discussed, elsewhere on this and the Rotax Owners Forum - its a gimmick!)😈

Hi Blueadventure, Can't quite work out, are you are for, fence sitter, against, the Big Tube (BT)t?? Say for a moment the BT does what its supporters claim - smoother running and lower rpm. Starting with rpm - Rotax advise against extended low rpm operations as this will almost certainly damage the gear box - So no benefit! Smoother running - Without data this is just a perceived benefit. Nothing wrong with perception but when you are trying to promote a product/modification, I will always want data ie proof. Then you need to consider the engines state of "tune" ie Was the engine that the BT was fitted to, recently serviced, carburettors balanced, plugs in good condition , etc On the last point, if the BT smooths out a badly running engine, this is a good thing - assuming its not masking an impending problem. I am not an engineer, however my understanding of the Rotax balance tube is that its there to smooth out/make good, any small differences in vacuum between the two induction systems. No significant volume of air flows back & forth in the tube. The proof for this is simple - when doing the pneumatic carby balance, you run the engine with the balance tube disconnected/shut off and the engine runs just fine (smooth) when carby's are balanced. Fitting a BT, will not improve on the action of the Rotax balance tube. I am certain Rotax would have adopted such a simple enchantments if it works as promoted.😈

This "modification" has been extensively discussed on Rotax Owners Forum. Latest revival can be found at https://www.rotax-owner.com/en/general-tech-discussion/6709-polishing-intake-manifolds?start=50 My summary of the discussion: Supporters rave about perceived smoother running /lower idle speed No empirical supporting evidence. Most can't see how it can work/make a significant difference to engine performance. A few die hard supporters refuse to believe its a con job Note; that Rotax engines should not idle below about 1400 rpm, as gearbox damage may occur, recommended extended idle 2000-2500rpm😈

"Tomorrow" turned out to be 8 days later (yesterday). Did an hour. Bit warm under the bubble ( 20C @ 5500') AvTraffic a non starter, due to this computer luddite not realising that a whole heap of "stuff" needed to be selected ON (hope I have now done it correctly). Will do a review after the next flight. For now - Noticed a change in my intercom; Volume needs to be turned to Max, then turned down on headset. I usually do a "click" check, short press of transmit button, on my intercom - doesn't work any more - cant hear the click. Cant explain it, but headset/intercom seems dead - to the point where I did an Any Station Radio Quality Check - came back 5/5. This is the Six Aviation Bluetooth Adapter - not the AvTraffic Should not be related, iPad / WiFi connection with my SE2 dropped out ?? Also lost OzRunways traffic (blue bubble) alerts, for a brief period?? The third event of this nature. I also noticed, after trying, unsuccessfully , to "fix" the AvTraffic issues, in the air, my OzRunways was very slow to come back on ??😈

The above has a 2 3/4" flange. FYI: The similar filter, with a 2 1/2" flange, K&N part # SN-2540, used by many Rotax 912's, may have been discontinued.😈

Does it strike you as a bit odd, that the Dayco cap you have referred to is a pressure cap - the coolant reservoir should be at ambient pressure. I guess if the cap fits, it can easily be modified, using a 2- 3mm drill bit.😈

Dont know the dimensions but what about an oil container cap? Another thought bubble - the collapsible jerry cans/bladders, have a cap which can be ordered separately 😈

I cant be certain but I think you are incorrect. Rotax will supply a basic 912 ULS engine, for which you can including exhaust , air inlet/management , remote oil tank, coolant & oil heat exchangers at a price($$$$?). What you or the factory do with the component's is the choice of the purchaser. Rotax do not supply, for the 912 carburettor engines, fuel reticulation components other than the fuel distribution manifold . Factory's often opt for locally or inhouse, made components - oil/coolant heat exchangers, custom exhaust system & engine mounts, probably due to cost savings and possibly cowling dimensions. I have seen some really weird looking exhaust systems, that are unlikly to follow Rotax standard's. The exhaust system on your Evector being a case in point. 😈

You are not entirely wrong - many airboxes are made by the aircraft factory, as are mufflers and engine mounting systems, however Rotax make all of these items as well. 😈

The air box pictured looks to be a Rotax product. Mine, a home made, is diffrent in a number of ways - location of float bowl breather tubes spigots, length of carby tubes, presence of a hot air inlet, etc😈

The following is speculative; Yes there will be heat transfer, how much this raises the air temp in the box, will depend on the air flow (speed) & volume. The air temperature entering the carbys will also be effected by the ambient temperature ie if cruising along at 7500ft, OAT - 2C, the temperature rise may only be a degree or two. 😈

"While I was taught to use carb heat when pulling power the instructor commented that on most 912ULS the carb heat did not make much difference. He is not the only experienced Rotax user that I have heard say this." Its a widely held belief that Rotax engines do not get carby ice. For sure they are resistant to icing but to think they never get ice is one big mistake. My advice; If the engine is fitted with a manual carby heat system - use it for every reduction in power (landings,stalls or just going to loitering power). Its a good habit to cultivate and will stand you in good stead should you transition to other engines more prone to carby icing.😈

Coolant heated ie plumbed into the cooling system.😈