Cleaning the oil tank?

[FastEddieB]

My Sky Arrow maintenance checklist calls for the oil tank to be cleaned with each inspection.

 

A few questions:

 

1) Why? I've owned lots of vehicles with 4-stroke engines and oil tanks (including a Buell* and a KTM and a Polaris ATV now), and none of them have required regular cleaning. Is there something different about the ROTAX?

 

2) Is cleaning more likely to be needed if running 100LL?

 

3) Is it enough to visually check the tank for cleanliness?

 

4) Can the tank be cleaned in place? Removing it from the Sky Arrow is a royal PITA. I was thinking about draining the tank and then maybe sloshing some kerosene or something around in it with something like a bottle brush and then just flushing it out well. Is this a terrible idea?

 

I'm asking both for myself and a friend who's in the middle of an "annual" and would like to know.

 

Thanks in advance!

 

 

*the Buell actually carries its oil in its swingarm, and I had a Yamaha that carried its oil in its frame. Routine cleaning of either would also be a PITA, and I don't think its ever done, at least not routinely.

[Runtoeat]

Ed, we'll have to let the experts chime in here but my limited experience with the Rotax results in just seeing a thin coating (less than 1/64") of sludge on the bottom of my tank whenever I've gone to the bother to clean it at an oil change and this is letting the change run to the full 100 hours. I have recently gone to oil changes @ 50 hours and due to this, there really won't be anything to clean out of the oil tank if I do take it apart. I can't answer your question regarding use of 100LL since I don't burn this fuel.

 

Side note, I have seen some really nasty looking sprague clutches that have locked up and failed. These were packed with lead sludge and were removed from Rotax engines where 100LL is used! :-(

[Roger Lee]

Hi Eddie,

 

This isn't an issue if you are using 91 oct. If you use 100% 100LL then each annual or 100 hrs would be a good time to do this since you should be doing 25 hr. oil changes with 100LL. That gives you 4 oil changes. You can clean it in place. When you pull off each hose do not let any oil come out. Get a rubber cork and plug that line. If you drain these lines you will need to do an oil purge. Open the top of the tank and remove the insert with the attached tubes and then remove the screen. Open the bottom drain and clean with some carb cleaner or solvent. Then put I back together. Fill the tank with oil before you reconnect the hoses to keep any air introduction to a minimum. It's more a leading issue than anything else. If you use 100LL you will see the lead paste on the bottom.

[FastEddieB]

Hi Eddie,

 

This isn't an issue if you are using 91 oct.

 

I guess I'm at about 80% mogas, only resorting to 100LL on cross-countries, which isn't that often.

 

My friend, however, is almost exclusively on 100LL, so he has more of a concern.

 

Have you used your newfangled camera to inspect an oil tank? I hope to have one before my next annual in December.

[Roger Lee]

Hi Eddie,

 

Haven't had the chance to use the scope. I'm out of town in Flagstaff, AZ teaching a Homeland Security Class. .My next annual is June 13th. A Sport Cruiser from Big Ben Texas.

[FastEddieB]

If its just a thin layer of lead "paste", it sure seems like something like this soaked in something like mineral spirits or kerosene or carb cleaner would get the job done, as long as it was flushed well before refilling with fresh oil.

 

[Roger Lee]

Sounds good to me. The lead wipes right out and toss in a little solvent and it's gone.

[PhillyBaron]

To the brave souls who have succeeded at this: is it possible to just leave the hoses attached to the oil tank top connected to the source and return oil lines, remove the bottom, clean, and reinstall? I’ve gone to a winter use of 100LL due to the long periods of inactivity up here (northeast) and would like to do this with each 25 hr oil change. Also, would clamping the hose lines be an added measure of protection during the procedure?

 

Thanks Rotax Sages!

[Roger Lee]

It is possible to remove just the bottom and leave the rest in our CT application. The problem here would be that the outlet hose away from the tank would most likely leak most of its oil. Then a full oil purge would be needed.

You could disconnect the hose and immediately put a rubber stopper in the line. Hold it up and do not let the oil drain out. It wouldn't be any different than putting on an empty oil filter. Once the hoses are back on turn the prop by hand with the plugs in about 20 times to help make sure the out to the engine hose is full of oil. Technically Rotax would want a full oil purge done. The key is keeping the oil in the hose and not letting it drain out.

 

 

My recommendation would be to don't mess with it because you most likely haven't run enough 100LL through it to make a difference.

[PhillyBaron]

Thanks Roger for the reply. I'll heed your recommendation and wait to clean the tank during the next 100hr/annual. That way I can have the mechanic walk me through it once.

 

Lee

 

It is possible to remove just the bottom and leave the rest in our CT application. The problem here would be that the outlet hose away from the tank would most likely leak most of its oil. Then a full oil purge would be needed.

You could disconnect the hose and immediately put a rubber stopper in the line. Hold it up and do not let the oil drain out. It wouldn't be any different than putting on an empty oil filter. Once the hoses are back on turn the prop by hand with the plugs in about 20 times to help make sure the out to the engine hose is full of oil. Technically Rotax would want a full oil purge done. The key is keeping the oil in the hose and not letting it drain out.

 

 

My recommendation would be to don't mess with it because you most likely haven't run enough 100LL through it to make a difference.