582 with a cough

dabkb2

Dave Bacon
Joined
Sep 26, 2005
Messages
2,787
Location
Vista, Ca
Aircraft
Sport Copter Vortex 582, 2 KB2 90Mac KB3 582
Total Flight Time
529 hours
I have had a cough in my 582 for awhile now, but today it finally got fixed:rapture:. The problem has the primer for the carb. I'm truly happy to have it right finally, and in time for KBFF.
 
Tim - I'm charging the batteries now.
 
Dave, not trying to be hard on you, but with Rotax 2 strokes.... they should ran flawlessly, and if they don't then something is wrong with them, and that something has a high likelyhood of causing a engine siezure.

If your primer system had a leak in the hoses and that is what was causing the cough, then that means the engine was able to run lean and this is the most easiest way to burn up the pistons and cylinder.

If the primer was somehow flowing gas through it when you weren't pumping it, then that means your engine was running overly rich, and this would cause excessive carbon build up, and that build up will freeze the rings on the pistons and not allow them to expand and contract as needed and this will cause excessive wear and possibly a siezure at some point as well.

The only reason I post this is for you and others to understand that All 2 stroke aviation engines are somewhat picky about how they are operated. If you operate them properly, they are bullet proof and have potential to be more reliable than a four stroke engine. But they do not tollerate being operated while something is wrong with them as some four strokes are able to do.


If the engine had quit on you and you tore your gyro up, it would not be blamed on the fact that there was something wrong with the primer system, it would be blamed on the simple fact that it was a unreliable 2 stroke. And that is not fair, because if you take care of your two stroke it will be a strong and dependable engine.

Glad you got it fixed, but I would take the time to unbolt the exhaust mainfold from the side of the cylinders and take a peek inside the cylinders with a bright flashlight and see if the cylinder walls are scored, the pistons are scored and check the piston ring grooves and top of the piston for excessive carbon. This is a easy inspection that shouldn't take more than 30 minutes. Let me know if you need help on what to look for specifically in the cylinder and how to inspect the ring grooves
 
I agree Ron, the primer was letting the engine run rich, so there could be some carbon build up. It is better to be safe than sorry. How can I tell the rings are free? Will there be build up on them, or is there something more?
 
Great news Dave, less than four weeks left!!!

Next time you fly her at Nichols let me know Jerry and Greg want to come back and see you fly her!!
 
Ron is right on target, the rotax is a great power plant. i have (in the past) built lots of them from all types,and they are a must,,,, on everything being right.

hard to kill one if you have it right, but if you dont, it will let you know.....

most people blame it on the 2 stroke but 95% of the time it's because of being ran at high rpms or even sometimes low rpms not set up right, wrong fuel mixter,slipping belt that cause's overheat,leaks in the fuel and air system,and i have even seen it wired wrong on the points type and cause the egein to quit.not to mention the set up of the carb or carbs-- jets,fuel valves ,trash,even jell after setting for long time and then being ran. and there is alot more to go with it.

i am not saying that the rotax is a bad idea to use, as haveing all this to keep in mind. it is a good and sometimes perfect engein to use on some application. weight to hp is hard to top when it comes to rotax.

at one time in the past i had rotax call me up to be a rep for repair in my part of tennessee because i had bought so many parts and tools manuals exc. even the collection of rebuild tapes they offerd.
i dont know for sure but some where around 15 to 20 rebuilds in one year.

the rotax will take a lot of punishment and keep right on ticking if set up right. that's a fact.:yo:
 
I agree Ron, the primer was letting the engine run rich, so there could be some carbon build up. It is better to be safe than sorry. How can I tell the rings are free? Will there be build up on them, or is there something more?

Just unbolt the exhaust manifold from the side of the cylinders and push it out of the way, then looking into the cylinders slowly turn the prop till one of the pistons is in proper position with the exhaust port. You want to position the piston to where you can see the rings ( there are two of them, one right at the top and one slightly below that one ) Then take a flatheaded screwdriver and gentlely push in on the rings, they should be able to move inwards without too much pressure, and they should also be able to move side to side just a little, if they are carboned up they may not push in at all, and they will likely not be able to move side to side any. After you check the first piston you will need to move the prop to position the other piston to check it.

While your in there you should move the prop to put the piston below the port and look in with a flashlight and check the cylinder walls for any scratches or score marks that are in a straight up and down direction. There should be some hone marks on the cylinders, these look like fine scratches in a cross or X pattern, but there should be no vertical scratches or marks at all on the cylinders or pistons.
 
Thanx Ron, that is what I planned to look for, but the rings are pinned and shouldn't move much. I will check the spark plug and compression, and look at the cylinder wall as well as the rings. What compression should be good?
 
Responsible Ron !!!

Responsible Ron !!!

Ron's post sounds like something I would write... the only difference is that I would have a stack of hate mail.... for picking on someone.

Seriously a gyro is not a car or motorcycle. 2 strokes develop fatal problems in short order and must be operated with care and concern.

Your problem was a tricky one but not totally out of the ballpark so to speak.

Rotax has a carbon cleaning schedule and procedure. It might be a good idea to go and do this carbon service now before you permanently damage a cylinder or piston if you have not do so already.

Small problems always start as small problems and then grow into big problems.

Spend the time, money, and inconvenience now before you have to do so on murphy's terms !

Good luck.

Jonathan
 
Hi John, I do not plan on flying at Nichols until after KBFF. I hope to fly at Hemet soon maybe tomorrow, for sure next weekend.
 
Jonathan

Jonathan

I agree, a little preventive matinace will me in the future. Is ther somthing I can run through the motor, or do I have to dissasamble and clean?
 
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