Excessive carbon build-up on 582

[georgeh]

I have had 13years experiece with 2 stroke engines and have never experienced so much trouble with some kind of build up on my spark plugs as i have in the past 6mts. I have also heard trikers talking about the same symptoms i experienced when the plugs develop this build-up. One guy was giving his petrol away, and i wanted to know why. When he told me the symptoms, i told him to check the plugs, and true as nuts the plug gap was cloging with carbon. When i first experienced it, the engine would hold 6200rpm for about 5 seconds and the drop to 4000rpm. On inspection i found a build up of what resembled filings standing up on a magnet, on the plug. Most recently my engine was picking up a vibration at 5000rpm, and a friend said it was probably my prop out of balance. After it got progressively worse over a broader rev range, i decided to check the plugs which were about 10hrs old, and again, a build-up on the plugs. After a clean no more vibration. I hear more and more guys talking about engines not running smooth.
I only use fully synthetic Motul 600, which i believe is far superior to the oils i see most 2 strokers using. I know my motor and another 582 that had 300hr checks that still had 100% hone marks, which prooves the 2 stroke is good.
Anyone else out there discovered this problem?

George.

[Petrodactyl]

This one is difficult to work out. some suggestions:

My bible on setting up carbs on the rotax 2 strokes is from Rainier Lammers (MGL). In it he points out that reading engine setting from plug colour on 2 strokes is as good as reading tea leaves, because of the the wide range of fuel mixture that the engine experiences.

However, what you describe sounds like mixture problems. If the deposits have a sort of brown baked-on look like the glaze on handmade pottery, this is an indication of overheating of the plug, and the usual cause of this is a mixture that is too lean (ie. not enough fuel in the fuel/air mixture) This would mainly result from the engine running lean for extended periods.

There can be many causes. There may be an air leak at the carb. Usual ones are are from a cracked or perished oil injection port cover (little rubber plug on the side of the carb throat) or the carb sockets. The main jet needle may be at the wrong height, worn or the incorrect needle for the engine or conditions. The prop pitch might also be a cause, as too high revs. at cruise (ie too fine a pitch) will cause the engine to run lean. Maximum revs for the rotax 2 strokes is 6800, with an optimum cruise of around 5000. Overheated plugs or cylinder heads due to a lean mixture can also lead to detonation due to the fuel igniting too early. This can seriously damage an engine if left unchecked.

If the deposit is more black and sooty, then the cause could be too rich a mixture. This can be caused by needle problems or an engine that is 'lugging its prop - ie. trying to turn a prop with too coarse a pitch. This results in too much fuel from the wide throttle openings at reduced air flow.

The only other cause can be the fuel or the oil. Old fuel (fuel that has been standing for a couple of months) is probably safest in your lawn-mower. Also, you never really know what you are getting from the pump - there is always a chance of contamination. The wrong oil can also cause it - although its lubricating qualities may be good, it might not handle that particular combustion environment.

If you do discover the cause, please let us know.

[georgeh]

Hi Christian
Thanks for the response. I have lots of experience with jetting and reading the plugs. I'm happy with the jetting, and egt. Engine water temp max 80 degrees celsius in head and EGT max 580-600 degrees celsius. If anything i may be a little rich, definately not lean, i'm not getting that black oily carbon building up to much, its those pieces that stand up and look like iron filings, that worry me.
I use BP uleaded, we 2500 ASL at Light Fight. Have a huge suspicion its the fuel, even thou i fly regular. Maybe the filling station has old fuel. Not a very busy one. Going to try another drand and a different filling station. Am hoping to get a response from more guys and find a lot more 582's with a the same or similar problem.
Thanks so much for your input.
Regards
George

[Boet]

Fit an Auto-lube system, and use TCW-3 super outboard plus oil like the operators manual says, and no more problems. Is it THAT difficult?

[Petrodactyl]

Hi George

Have you solved your problem yet?

Asking around, this is not a problem many people have had, so it is likely an isolated cause, like fuel or oil.

Fly Safe

[georgeh]

Hi Christian, haven't found problem yet. Flew out most of the old fuel tuesday. New plugs today and fresh fuel from a different filling station. Will have to give it a couple of hours before i'll be able to get a reading off the new plugs.I'll definately post the results. Might have to tuck my tail between my legs with the Motul 600. Burn rate may not suitable for this application. Will change oil next if the fuel change doesn't solve the problem. Maybe have to try the outboard oil, Boet.
Regards George.

[Boet]

George, is it premix or auto lube? I can for the life of me, not understand why guys keep on chucking the auto lube systems out. It is fool-proof, and VERY effective. Your engine runs at optimum fuel-oil ratio all the time. I would like some feedback from you on this one. Started using the TCW-3 spec yet? I tend to cock a beady eye on the synthetics.

[georgeh]

Hi Boet,
I have seen other posts of yours about the oil controversy. My plane came with the auto lube, but was not connected and was running pre-mix. Coming from two stroke racing background with karts i went straight onto motul 600 which i'd used forever, without problems Premix. I've always been assisted and advised by a friend who was technical advisor at Yamaha SA. He also believes that the auto lube is the best option. Remember i've only been flying two strokes 14mths. The biggest problem i heard about from early days, was the cranshaft saga. I have heard so many stories about oils, auto lube and pre mix its just not funny. My mate recons the problems are not caused by the auto lube but probably the kak oils been used. In the motorcycle business he often went to assess claims where a motor cycles with auto lube had seized, and everytime the problem was caused because the 2 stroke reservoir had been run empty, then filled, and by then it develloped an air lock and wasn't bled. Therefore no oil feed until bled! You absolutely right, i think most people dont understand that at different revs the engine reqires a different ratio of oil to fuel, therefore the autolube should be best. I'm not going to change oil until i've fitted new air filters and tried changing the jetting and eliminate them as the problem. My AP says its a definate no to outboard oils because they run much cooler? My autolube was removed about 4mths ago at its 300hr 8yr service. Haven't been able to fly here in natal much with the kak weather, thats why i haven't got to the root of the problem yet. Can you fill me in on the 300hr crankshaft replacement saga?

[Mogas]

Reading this whole story, it also sounds to me like the Motul is not for the 582. Whilst it may have exceptionally good lubricating properties it is probably not burning off nicely at the 582 water-cooled operating temperature, leading to your fouled plugs.
There are others here who have way more 2 stroke time than me but this is my take on it.
Mogas

[Boet]

George, it seems tht this saga has been around as long as 2-stroke engines! So many experts, so many opinions. I have definately been flying 2-strokes for more than 14 months! Belief me when I tell you the right thing. Autolube, TCW-3 spec Super outboard plus, as the book says, and NO problems.
The 300 hrs have now been extended to 600 hrs, with a non-invasive inspection of the pistons and rings at 300 hrs. I can, for the life of me not see what changed. I know of many 582`s that did more than 1000hrs and were still fine. However, it is of UTMOST importance that you clean oil and maintain the sir filters REGULARLY.
One of my clients recently did a 300 hr overhaul on his 582 mod 99 with autolube.. He listened to the wrong "expert", and used super chainsaw. His pistons and rigs were shot, and had to be replaced. The rings were stuck in the frooves and HEAVY carbon build-up.
His neighbour in the hangar nexr door overhauled his 582 mod 99 with autolube. He read the manual and ignored the "experts". Used TCW 3 only. Loose rings and no carbon build-up. No need to replace anything.
Need I say more?? I rest my case.
Fly safe. ( And enjoy the rain ....... here it is so dry, the bushes are chasing the dogs.)

[georgeh]

The TM K9 motor and Yamaha motors i used the Motul on were always operating between 10 000 and 14 000rpm, maybe thats where it works best, not 5-6000rpm??????????????? Think i'm gonna jump in the deep end and try another 2stroke!!!!!

[Boet]

Jaaa swaer. Forget about motorbikes when you are flying with a Rattex 2-stroke. A COMPLETELY different thing.

Fly safe.

[Boet]

And PLEASE PLEASE PLEASE re-connect the auto lube system. You PAID for it, USE IT.......

[georgeh]

Boet can you tell me in what manual and where does it tell you to use TCW3 outboard oil?
Dankie Boet!

[Boet]

582 operators manual.