Roger Lee Posted November 7, 2010 Report Share Posted November 7, 2010 Fun questions to stimulate and educate. (right off a Rotax test) What is the firing order for the Rotax 912? answered What is the oil content of a 912 engine? answered What type of oil sump is used on the 912? answered What is the integrated alternator output? answered What do the crankshaft drive gear and the dog gear have in common? answered What is the 5th trigger coil pickup used for? answered How is the oil returned from the crankcase to the oil tank? answered How are the cylinder heads on the Rotax 912 cooled? answered What is the cubic inch displacement of the Rotax 912? answered What is the accepted gearbox friction torque, upper and lower limit? answered What is the gear reduction ratio for the 912S series? answered What does the cylinder head temperature sender measure? answered Where on the engine is the manifold pressure taken? answered What do the oil temp and cylinder head temp senders have in common? answered On the carb, lifting the jet needle from the second to the third notch will do what? answered What type of Loctite is recommended for sealing the gearbox surfaces? answered If you do not have a tight seal on the top of the carb what will result? answered What is the start up timing for the Rotax 912? answered What is the torque for the 912 spark plugs? answered What is the new spark plug gap settings? answered How many double ignition coils are necessary to operate the 912 engine? answered What does CDI ignition stand for? answered How many charging coils are used on the Rotax engine ignition system? answered How often should the coolant be replaced? answered Extra credit: Through where does the vacuum in the venturi activate the carb piston and diaphragm assembly? answered What will occur if the crankcase locking pin is removed and the bolt is not installed in its place on the crankcase and the engine is started? answered What type of coating is on the 912 cylinder walls? answered Why are you not allowed to rework the valve surface on the Rotax 912? answered How is the correct pressure established in the carb float bowl and by what method? answered If you don't know these that's perfectly ok and the answers are in the maint. manuals and operators manual. Link to comment Share on other sites More sharing options...
coppercity Posted November 8, 2010 Report Share Posted November 8, 2010 Ok I'll embarrass myself again on a few.....If I was smart I'd look in the manual, but this way is more fun! Hi Eric. No dumb answers here and everyone shouldn't be worried about a wrong answer. This is how we all learn. What is the firing order for the Rotax 912? I know you told me this before, but not sure..1,3,2,4. Correct. 1&3 are on the right and 2&4 on the left. What is the oil content of a 912 engine? 3qts is all you need, but you might squeeze in another 0.2qts if you like scrubbing the belly. 3/4 correct. 3 liters or .793 US gals. What type of oil sump is used on the 912?dry sump Correct What is the integrated alternator output?250w at 13.5v Sorry, wrong What do the crankshaft drive gear and the dog gear have in common? What is the 5th trigger coil pickup used for? How is the oil returned from the crankcase to the oil tank?blow by during the compression stroke of the piston leaking back to the case forcing the oil thru the return line. Correct, the actual answer I was looking for was "Crankcase pressure". How are the cylinder heads on the Rotax 912 cooled? Liquid cooling. Correct What is the cubic inch displacement of the Rotax 912? 86.5 cu/in Sorry not correct. What is the accepted gearbox friction torque, upper and lower limit? What is the gear reduction ratio for the 912S series?2.43 to 1 Correct What does the cylinder head temperature sender measure? Where on the engine is the manifold pressure taken? What do the oil temp and cylinder head temp senders have in common? On the carb, lifting the jet needle from the second to the third notch will do what?enrichen the mixture when less than full throttle. Correct What type of Loctite is recommended for sealing the gearbox surfaces? If you do not have a tight seal on the top of the carb what will result? What is the start up timing for the Rotax 912? What is the torque for the 912 spark plugs?177 in/lbs...to tight. Correct. On a cold engine and yes I think it's to tight, too. What is the new spark plug gap settings? How many double ignition coils are necessary to operate the 912 engine? What does CDI ignition stand for? properly?capacitive discharge ignition. Correct How many charging coils are used on the Rotax engine ignition system? How often should the coolant be replaced?every 2 years. Correct. If you guys haven't done yours do it at the next inspection. Extra credit: Through where does the vacuum in the venturi activate the carb piston and diaphragm assembly? What will occur if the crankcase locking pin is removed and the bolt is not installed in its place on the crankcase and the engine is started? What type of coating is on the 912 cylinder walls? Why are you not allowed to rework the valve surface on the Rotax 912? How is the correct pressure established in the carb float bowl and by what method? Ok guys don't let Eric answer all these questions, jump in there. This is a good education for you on your Rotax and to help work with your mechanic. It also helps you learn the Rotax manuals. After a few days I'll whittle down some of the questions that have been answered. Link to comment Share on other sites More sharing options...
FlyRatz Posted November 8, 2010 Report Share Posted November 8, 2010 Funny questionaire. I'll do my very best :rolleyes: What is the integrated alternator output? Maint manual says 12 V, 20 A DC. The AC Voltage is around 150 Volts. The Ducati Reg/Rec delivers around 13.8 V DC. Correct What do the crankshaft drive gear and the dog gear have in common? What is a "dog gear"?? Is there a "cat gear" as well?? What is the 5th trigger coil pickup used for? Tach signal. Correct What is the cubic inch displacement of the Rotax 912? 82.50 cu/in Correct What is the accepted gearbox friction torque, upper and lower limit? Min 600 Nm, max 800 Nm. It is better near 800 than 600 Nm. Sorry, wrong What does the cylinder head temperature sender measure? The temperature of the aluminium. Not the coolant. Correct. The metal temp Where on the engine is the manifold pressure taken? At the intake balancing tube. Correct What do the oil temp and cylinder head temp senders have in common? The Ground. Sorry, wrong What type of Loctite is recommended for sealing the gearbox surfaces? Loctite 5910. Correct If you do not have a tight seal on the top of the carb what will result? Too lean the mixture. The piston does not move to its maximum upper position at WOT. Danger of engine overheat. Yes, but why. What happens? What is the start up timing for the Rotax 912? It is 4° before upper point. Correct What is the new spark plug gap settings? 0.8 mm Sorry, wrong How many double ignition coils are necessary to operate the 912 engine? To run it, maybe 1. To run it proper 2. To run it safe 4. Correct, 4 is correct and normal operation How many charging coils are used on the Rotax engine ignition system? Two. One for each ignition circuit. Correct Extra credit: Through where does the vacuum in the venturi activate the carb piston and diaphragm assembly? There is a hole in the piston. Correct. 2 holes in the carb piston What will occur if the crankcase locking pin is removed and the bolt is not installed in its place on the crankcase and the engine is started? Oil will not returned to the external oil reservoir. Correct What type of coating is on the 912 cylinder walls? It's Nikasil (Mahle) Sorry, wrong (close though) Why are you not allowed to rework the valve surface on the Rotax 912? The valves are armour-plated. You would injoure the plating. Correct How is the correct pressure established in the carb float bowl and by what method? The bowls are connected via a tube. This tube runs through the airbox and has a whole in the middle. Through this balancing tube, different air-pressures between the two bowls can not happen. Because of this, the same vacuum pressure takes always the same amount of fuel. Correct Markus Link to comment Share on other sites More sharing options...
Runtoeat Posted November 8, 2010 Report Share Posted November 8, 2010 Roger, this is educational and good info to have. I've started a word document with my answers that you may be able to edit to keep track of all our replies and eventually post with correct answers after everyone takes their best shot. No worries if you don't want this. roger lees questions.doc Link to comment Share on other sites More sharing options...
Roger Lee Posted November 8, 2010 Author Report Share Posted November 8, 2010 Hi Dick, I read your attachment. You have some of the right answers that aren't posted yet. Take a shot at them on the board. Link to comment Share on other sites More sharing options...
FlyRatz Posted November 8, 2010 Report Share Posted November 8, 2010 Ha, I shot the extra credit :D I'll take the red candy Link to comment Share on other sites More sharing options...
gisurvey Posted November 8, 2010 Report Share Posted November 8, 2010 thanks roger - very instructive questionnaire. What is the accepted gearbox friction torque, upper and lower limit? 30-60 Nm; Correct What do the oil temp and cylinder head temp senders have in common? are the same; Correct What is the new spark plug gap settings? new: 0.6-0.7mm; old: 0.7-0.8mm; Correct What type of coating is on the 912 cylinder walls? Gilnasil? Both Correct but officially...nikasil [see attach HMM excerpt] alec Link to comment Share on other sites More sharing options...
Roger Lee Posted November 8, 2010 Author Report Share Posted November 8, 2010 Wow, you guys are good, but two more to go. Then maybe I'll remove the easy questions and come up with a few harder ones? :blink: Link to comment Share on other sites More sharing options...
Roger Lee Posted November 10, 2010 Author Report Share Posted November 10, 2010 Who's going to get the last two questions? Link to comment Share on other sites More sharing options...
Runtoeat Posted November 10, 2010 Report Share Posted November 10, 2010 Who's going to get the last two questions? What are the last two questions Roger? Link to comment Share on other sites More sharing options...
gisurvey Posted November 10, 2010 Report Share Posted November 10, 2010 What are the last two questions Roger? "...last two unanswered questions..." First post - in blue. Link to comment Share on other sites More sharing options...
coppercity Posted November 11, 2010 Report Share Posted November 11, 2010 Ok Roger I will try the last carb question. Looking at the diagram it would seem that if there was not a good seal on the top of the carb it could not create the vacuum needed to raise the main jet to allow the required fuel to get thru. That would mean a really lean mixture on that carb. Just a guess! Hurray, You are correct. It will cause an air leak which in turn will cause the mixture to be lean, which will cause that it to run hot. Link to comment Share on other sites More sharing options...
Admin2 Posted November 11, 2010 Report Share Posted November 11, 2010 Ok, I guess the dog has to answer the last question. What do the crankshaft drive gear and the dog gear have in common? These two have matching 6 digit serial numbers. Correct Mr. Dog Link to comment Share on other sites More sharing options...
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