I fired up the Rotax for the first time this morning. Started right off, but with the throttle full closed the lowest RPM I could get was 3470...not the 1800 or so that I wanted. Oil pressure, etc, seems OK. Due to family responsibilities I can only get in 3 hours or so each day on the plane, so I had to leave it until tomorrow for trouble shooting. A quick peek through the oil door didn't show anything wrong at the right carb, so it will be interesting to see what the trouble is...prop set for max 'bite' so my preliminary thinking is that it is carb related. More tomorrow.
Van's Air Force
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First Engine Start
- Thread starter JohnF
- Start date
Geico266
Well Known Member
Double check the "closing" distance on the carbs. There is a procedure for setting the idle before first start. I think it is .004 off the stop, but double check it and your setting before the next start. You should not exceed 2,500 RPM until the oil is warmed up to 120F.
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Maintenance Manuals
That's interesting...the maintenance manual on a CD supplied with my Rotax is dated Sept, 2007, and the latest appears to be October, 2009 per the information from Mr. Horn, above. I have asked Van's if I could get a current CD since there are some obvious differences...like the spark plug gaps that was discussed earlier on this site. The CD I have does not even have a section 12-20-00....all that area is simply 12-00-00.
I know I set things per the RV-12 plans but will recheck things again tomorrow.
That's interesting...the maintenance manual on a CD supplied with my Rotax is dated Sept, 2007, and the latest appears to be October, 2009 per the information from Mr. Horn, above. I have asked Van's if I could get a current CD since there are some obvious differences...like the spark plug gaps that was discussed earlier on this site. The CD I have does not even have a section 12-20-00....all that area is simply 12-00-00.
I know I set things per the RV-12 plans but will recheck things again tomorrow.
Interesting. Rotax has a web site, www.rotaxowner.com, with all the latest. Until a few months ago it was all free. Now they have started charging for everything but the things that affect safety of flight. Not sure if the manual I refer to is under the free or pay part since I broke down and subscribed. Until 6/30 you can subscribe for $29.95/year then it goes up 20 bucks.
They have a good video under the subscription part which takes you through the carb set up and sync.
Anyway, under the free part you can research all the bulletins for your engine by S/N and, I think, get email bulletin updates once you register your engine.
They have a good video under the subscription part which takes you through the carb set up and sync.
Anyway, under the free part you can research all the bulletins for your engine by S/N and, I think, get email bulletin updates once you register your engine.
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The engines are generally supplied with the idle set pretty close.
If you are getting that high of an idle (BTW Larry is correct, you should not run the engine above 2500 RPM until oil temp has reached 120 F.) I would suspect one of two things.
The cable stop on both or one of the throttle cables is hitting the adjusting barrel before the throttle arm on the carb.(s) reaches the throttle stop screw(s). Pull the throttle all the way to idle and see if the tabs on the carb. throttle levers are touching the adjustment screw. 3500 RPM would probably require you to be missing teh screw by at least an 1/8".
The other possibility is that the starting carb. valves (commonly referred to as the choke) are not being controlled correctly and are staying partially open when you move the choke control to off. Make sure that when the control is in the off position (pushed all the way in), that the springs move the control levers all the way against the stops.
longranger
Well Known Member
Another possibility?
Are you 100% sure that the tach in your EIS is set up correctly? Half of 3470 is 1735, pretty close to what it shoud be. If you have access to an optical prop tach, it might worth a shot to take a reading, multiply by the gear ratio, and see what you get.
Just a thought...
Are you 100% sure that the tach in your EIS is set up correctly? Half of 3470 is 1735, pretty close to what it shoud be. If you have access to an optical prop tach, it might worth a shot to take a reading, multiply by the gear ratio, and see what you get.
Just a thought...
First Engine Start Update
This morning I checked the "choke" adjustment...both full on and off hit the stops as they should.
The throttle had been set per the plans: Stop screw down to .004, then 1.5 turns...with cable stop loose.
Didn't seem to do the trick, so I let the cable stop loose, set the stop screw to a medium drag on a 0.002 feeler gauge, and tightend things up. Tightened the cable stop.
Started the engine...normal idle easily obtained.
So that problem is solved; now one other thing: The CHT went a few degrees over the 248F max. On a Lycoming/Continental a new engine can be expected to show some high CHT until breakin has occured. Coolant level is between min and max, hose from radiator pretty warm so water seems to be moving through the system.
Had fuel pressure of 1.9PSI, so I drilled two more holes in the fuel cap per other's experience...will see how that works on next runup.
No output from alternator...seems we go from one problem to the next as a fairly normal sequece in building, had same general chain of events building the RV-6A.
Thanks for comments above and would appreciate same regarding CHT.
This morning I checked the "choke" adjustment...both full on and off hit the stops as they should.
The throttle had been set per the plans: Stop screw down to .004, then 1.5 turns...with cable stop loose.
Didn't seem to do the trick, so I let the cable stop loose, set the stop screw to a medium drag on a 0.002 feeler gauge, and tightend things up. Tightened the cable stop.
Started the engine...normal idle easily obtained.
So that problem is solved; now one other thing: The CHT went a few degrees over the 248F max. On a Lycoming/Continental a new engine can be expected to show some high CHT until breakin has occured. Coolant level is between min and max, hose from radiator pretty warm so water seems to be moving through the system.
Had fuel pressure of 1.9PSI, so I drilled two more holes in the fuel cap per other's experience...will see how that works on next runup.
No output from alternator...seems we go from one problem to the next as a fairly normal sequece in building, had same general chain of events building the RV-6A.
Thanks for comments above and would appreciate same regarding CHT.
Glad you solved your idle problem.
I think you will find that extra vent holes will have no effect on the fuel pressure.
How long did you run the engine on the ground, and at what power setting?
Ground operation does not put a lot of air through the coolant heat exchanger, but unless the engine is run on the ground at high power for an extended period, the CHT's should stay way down in the green
High CHT Update
Third engine run...still get high CHT after a timed 6-minute run. G.P. inputs were set to #1 to CHT sensor for left side, #2 sensor set to right side.
Initial overnight readings had CHT and Oil temp within a degree or two.
OAT on D-180 upon turn on read negative 46-degrees F, and density altitude at 2,180-ft. Checked settings: OAT sensor type 1, two-wire type. Were as they should be. OAT "connected" to GP#3, general purpose input, as it should be. OAT was totally normal when I closed the plane last night, and it had not been started or moved.
Going to pull the cowling and recheck cylinder head coolant hose connections/routing, though it seems highly unlikely they could be wrong.
JohnF
Third engine run...still get high CHT after a timed 6-minute run. G.P. inputs were set to #1 to CHT sensor for left side, #2 sensor set to right side.
Initial overnight readings had CHT and Oil temp within a degree or two.
OAT on D-180 upon turn on read negative 46-degrees F, and density altitude at 2,180-ft. Checked settings: OAT sensor type 1, two-wire type. Were as they should be. OAT "connected" to GP#3, general purpose input, as it should be. OAT was totally normal when I closed the plane last night, and it had not been started or moved.
Going to pull the cowling and recheck cylinder head coolant hose connections/routing, though it seems highly unlikely they could be wrong.
JohnF
John, it is still not clear to me what you are doing when you make an engine "run". Was this 6 minutes of idling? Full throttle? You should be able to run the engine for as long as you want on the ground, as long as it is at low power settings. If you can't, then something is clearly wrong with either the instrument reading (though it should be ok if it properly reads ambient temp when the engine is cold), or the cooling system for the engine. It is still not clear what you are doing during the ground test when you are getting these high temps.
Negative 46 degrees? Unless this was a typo, it sounds like you have something wrong with
CHT
No, not a typo - just overnight the D-180 decided that the OAT was negative 46-degrees F. (-46F) Was correct ambient temperature last evening when I quit the hangar. No increase of OAT indication when holding the OAT probe in my hand..usually that causes an increase right away. Plane was not
moved or started since I left the hangar the previous evening.
On the runup...I am idling at 1,800rpm possibly to 2,000....CHT and Oil Temps start out within a degree or two and the CHT just steadily increases...this morning it took 6-minutes at idle for the CHT to reach max of 245 (248 is listed as max)
Oil temp at that time only was 61-degrees, and oil pressure was 60p; engine really not yet warmed up.
Coolant hose from top of radiator warm to the touch and coolant level in overflow bottle had dropped slightly, but still well above min mark.
Tomorrow will re-check all coolant hoses, but since they had to be cut to a pretty specific length during installation it seems improbable some error could have happened there...also asking Dynon for their input re the weird OAT and CHT indications.
I am struck by the coincidence of Van's showing oil temp max and cht max as both 248-F - could be ok, but in looking at other websites I see some four cylinder Rotax engines in other planes had CHT max listed as high as 130C
(266F) and another one called for a CHT max of 284 - that really caught my attention because 248 (Van's) and this maker's 284F seems like a number transposition... though I doubt it is.
No, not a typo - just overnight the D-180 decided that the OAT was negative 46-degrees F. (-46F) Was correct ambient temperature last evening when I quit the hangar. No increase of OAT indication when holding the OAT probe in my hand..usually that causes an increase right away. Plane was not
moved or started since I left the hangar the previous evening.
On the runup...I am idling at 1,800rpm possibly to 2,000....CHT and Oil Temps start out within a degree or two and the CHT just steadily increases...this morning it took 6-minutes at idle for the CHT to reach max of 245 (248 is listed as max)
Oil temp at that time only was 61-degrees, and oil pressure was 60p; engine really not yet warmed up.
Coolant hose from top of radiator warm to the touch and coolant level in overflow bottle had dropped slightly, but still well above min mark.
Tomorrow will re-check all coolant hoses, but since they had to be cut to a pretty specific length during installation it seems improbable some error could have happened there...also asking Dynon for their input re the weird OAT and CHT indications.
I am struck by the coincidence of Van's showing oil temp max and cht max as both 248-F - could be ok, but in looking at other websites I see some four cylinder Rotax engines in other planes had CHT max listed as high as 130C
(266F) and another one called for a CHT max of 284 - that really caught my attention because 248 (Van's) and this maker's 284F seems like a number transposition... though I doubt it is.
There is no way the CHT's should go that high just idling the engine so either the temps are false or you have some type of cooling problem. If the system looks full when you remove the cap, then I would guess an indication problem.
There are different CHT's published for different reasons. One is because some people use Evans waterless coolant which allows the 285 F max but it is not as efficient, so the temps will automatically run higher. The different temps really aren't relevant to your situation because even if a higher temp was specified, you shouldn't be getting anywhere near the temps that you are getting to now while just running at idle.
Geico266
Well Known Member
John, I think Scott is onto something. Double check to ensure the coolant lines are going to the correct outlets and double check to ensure the radiuator hoses are in the correct locations. Not by the length of the hose, but by what the function is.
IF there is nothing wrong there is something hooked up wrong somewhere. The OAT is a clue.
IF there is nothing wrong there is something hooked up wrong somewhere. The OAT is a clue.
Jetguy
Well Known Member
Go to Harbor Freight and buy a Non-Contact Laser Thermometer for 26.00 and after it gets hot then shut down and shoot the cylinder with the laser and compare temps. If it shows good then shoot the small radiator tank. If your indications all match then i would bet the radiator fluid is not flowing correctly. John
http://www.harborfreight.com/automotive-motorcycle/diagnostics.html
http://www.harborfreight.com/automotive-motorcycle/diagnostics.html
Geico266
Well Known Member
Excellant idea. You could also put the CHT probe into boiling water. It should be reading 212F.
CHT Problem
I just ordered the infrared thermometer (now on sale for $19.99) and in the meantime I am going to pull the cowling, double check coolant hose installation, and try boiling water with the CHT sensor. I also feel this area is the problem. (Then I can get on to trying to figure out why the D180 thinks its 46 below zero !)
I just ordered the infrared thermometer (now on sale for $19.99) and in the meantime I am going to pull the cowling, double check coolant hose installation, and try boiling water with the CHT sensor. I also feel this area is the problem. (Then I can get on to trying to figure out why the D180 thinks its 46 below zero !)
Geico266
Well Known Member
A call to Dynon or Stein Air should be in order for that one.
MartySantic
Well Known Member
This has happened a number of times in industry. FME (Foriegn Mateial Exclusion plugs/tape, etc.) are used to keep the piping/tubing clean during work and then NOT removed on reaseembly.
Did you tape over or plug the cooling hose or engine inlet and forget to remove the plug?
Did you tape over or plug the cooling hose or engine inlet and forget to remove the plug?
CHT Overheat Problem Solved !
Yes, I considered that perhaps I had left a plug in a hose or something like that. I pulled the cowl and checked the coolant hose installation. All seemed perfectly per the plans.
I opened the mainifold cap -for no real reason at all - and there was a big "whoosh" sound...the engine had not been run since the day before so I knew there was no air leak in the system since it seemed to hold some sort of vacuum. For reasons I cannot explain I wiped the lip of the manifold and pinched the hose to the expansion tank and blew very hard into the mainfold..it seemed to "take" the air I was blowing....when I removed myself and looked into the manifold it was empty ! I suspect, but cannot be certain, that there was an air pocket or void in the system....I added a FULL liter of coolant to fill the manifold again.
Ran the engine for 10 minutes and the CHT only got into the mid 150F range and seemed to roughly stabilize there.
Could there have been a trapped air pocket? That's my only guess, and its just that: a wild guess, but whatever it was I am one happy camper that the problem has been resolved.
Now to see why the Dynon thinks that the OAT is 46-degrees below zero !
I want to express my appreciation for all the suggestions and offers of ideas; your help is genuinely prized.
JohnF
Yes, I considered that perhaps I had left a plug in a hose or something like that. I pulled the cowl and checked the coolant hose installation. All seemed perfectly per the plans.
I opened the mainifold cap -for no real reason at all - and there was a big "whoosh" sound...the engine had not been run since the day before so I knew there was no air leak in the system since it seemed to hold some sort of vacuum. For reasons I cannot explain I wiped the lip of the manifold and pinched the hose to the expansion tank and blew very hard into the mainfold..it seemed to "take" the air I was blowing....when I removed myself and looked into the manifold it was empty ! I suspect, but cannot be certain, that there was an air pocket or void in the system....I added a FULL liter of coolant to fill the manifold again.
Ran the engine for 10 minutes and the CHT only got into the mid 150F range and seemed to roughly stabilize there.
Could there have been a trapped air pocket? That's my only guess, and its just that: a wild guess, but whatever it was I am one happy camper that the problem has been resolved.
Now to see why the Dynon thinks that the OAT is 46-degrees below zero !
I want to express my appreciation for all the suggestions and offers of ideas; your help is genuinely prized.
JohnF
Lesson learned
JohnF,
Thanks for posting your problems and experiences. The lesson that I learned is to know system capacities and start with known quantities of fluids. Then measure quantity of fluid added. If the system will not accept the expected quantity, then investigate why not.
Some pumps that are designed for liquids must be primed to remove air. Perhaps your pump and passageways contained air and by blowing into the manifold, coolant was forced in. It reminds me a a toilet. It takes a little pressure (more water) to get the bowl to start emptying. Once flowing, it all siphons out.
Chances are that the low OAT is due to a bad connection. It is too bad that those connections are a pain to access. Good luck.
Joe
JohnF,
Thanks for posting your problems and experiences. The lesson that I learned is to know system capacities and start with known quantities of fluids. Then measure quantity of fluid added. If the system will not accept the expected quantity, then investigate why not.
Some pumps that are designed for liquids must be primed to remove air. Perhaps your pump and passageways contained air and by blowing into the manifold, coolant was forced in. It reminds me a a toilet. It takes a little pressure (more water) to get the bowl to start emptying. Once flowing, it all siphons out.
Chances are that the low OAT is due to a bad connection. It is too bad that those connections are a pain to access. Good luck.
Joe
