Great Trip Planned [email protected]#$% Rotax

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Great Trip Planned [email protected]#$% Rotax

Postby scubarider2 » Sun Jul 27, 2008 11:32 am

Ok....need some advice, sympathy, something to make me feel better about spending $20,000 on a Rotax 912uls.  Got up this morning and had a great trip for lunch planned.  Went to the hangar, got everything ready, turned the prop to check the oil and it was like I had the plugs out, very little compression.  I tried to crank it and it sputtered, no start.  Checked what I knew to check which isn't really much.  Tried again.  No start.  Flew beautiful yesterday low and slow over Lake Burton waving at all the boaters.  Now, I sit here grounded not knowing what else to do.  My engine is spotless, I change the oil every 25 hours, I take care of my plane.  All I can think of is to check all the plugs.  I will go back when it is cooler out and pull the plugs, retorque them, check the color.  After that, I am lost.
Any ideas and help would be much appreciated before I have to call someone to fly out and pay them to look at it.  Not sure who to call anyway in this area.
:cry:
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Postby Gary H » Sun Jul 27, 2008 1:27 pm

Hey Dennis,
Steve had the same problem, talk to him and see what he did.
I am still trying to figure out what to do about my gas tanks. I am going to have a good talk with Troy at Oshkosh this week.
Two years of building and I can't fly!! Thanks for the post.
Gary

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Postby stede52 » Sun Jul 27, 2008 3:40 pm

Dennis
that had also happened to me and after turning the prop a number of times and turing it over with the starter I started getting compression back in a couple cylinders.  When I did get it started it ran extremely rough, which I had to do by increasing throttle not using the choke, I let it run for a couple of minutes to warm things up and then shut it down for about 10 minutes.  tried it again and all cylinders came on line and it ran and flew great.  After the flight I've had it started three separate times, all cold starts with the choke and it started up just fine.  I thought my problem what due to the fact I had done about an 1.5 hours of high speed taxing, not exceeding 3000rpm, which caused some build up of somekind on the valves which made the them stick open.  But that doesn't seem to be your issue. I hope the h#$%#ll it's not the tanks and the fact the fuel is dissolving the softer inner finish coat layer in the tanks.  Gary and I have been doing lots of talking about this to other fiberglass sources and according to them Just's tank manufacturer is doing something wrong if the inside skim coat is not hardening, either not using a finishing resin or the wrong amount of catylst. According to Troy running two or three tanks thru the engine cleans the tanks, but according to the other fiberglass sources they shouldn't be sticky in the first place. Who's right????Needless to say we are concerned!!!!

steve
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Postby gme9261236 » Sun Jul 27, 2008 4:20 pm

look on the bright side, you didnt discover the problem in flight.
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Postby stede52 » Sun Jul 27, 2008 4:50 pm

I'm hoping its only a cold engine start issue and once everything gets to temp the problem with deposits/sticky valves goes away........if not there is not bright side, it's not like you can just pull over on the side of the road at 5000'.  I'm also going to use Sea Foam additive in my fuel to keep the valves clean.  According to Lonnie at South Mississippi Light Aircraft, they have been using Sea Foam fuel & oil additive in there 912s for about 6 years to keep the valves clean.  

Steve
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Postby scubarider2 » Sun Jul 27, 2008 5:18 pm

OK,  thanks for making me feel better.  I went back over to the hangar and decided to replace the plugs.  I pulled all of them and they seemed tight but not tight to spec.  Anyway, pulled all of them and replaced and torqued to 20neutons.  Pushed the plane out and bang.....started right up.  I am going to buy some sea foam and start using it on every tank full as well.  Here is the kicker though..... :(   When I was test flying some antifreeze was leaking on my foot!  So landed and found that where I installed the heater, the 90 degree elbows (2 of them) and broken.  So spent the afternoon taking the boot cowl off and taking the hoses off along with the heater.  So now she is grounded until I can find the right 90 degree hoses and reducers needed.
I also found that one of my strobes is not working so when I have the boot cowl off I will check the wiring for that.  
Always something it seems.
Thanks guys...like I said before you are the greatest!
Dennis
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Postby alan » Sun Jul 27, 2008 10:27 pm

If this ever happens again, pull a valve cover and pull the prop through while watching the rocker arms. Check to see if there is a gap between the rocker arm and the valve. If there is a gap you have a stuck valve. If the rocker arms don't move your lifters are not pumped up. Also, try pushing on each rocker arm where it contacts the push rod. You should have no more than .002".

Once you have purged the oil system the first time, your lifters shouldn't leak down. You should ask a Rotax repair station what your options are. As for stuck valves, maybe Marvel Mystery Oil or Avblend in the oil or gas might help there.

Good luck

Alan
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Postby stede52 » Mon Jul 28, 2008 12:33 am

We actually took off the #4 cover and the intake valve was stuck to the point there was a .25" gap.  but then the next day when I got the engine finally started as I describe below, the darn think ran great. I will be using Sea Foam in the oil just before my first oil change however the intake valve is a gas issue. thanks for all the responses and suggestions

Steve
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sticking valves

Postby KevinC » Mon Jul 28, 2008 9:01 am

Interesting timing.  Rotax-owners list just sent out notice on this new video on purging the oil system:
http://www.rotax-owner.com/exp/EXP-SI-912-018.htm

Sounds like it might be related?

K
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Postby scubarider2 » Mon Jul 28, 2008 11:39 am

I don't think that the oil system has anything to do with what is going on with me.  I think it is for those who have a fresh engine or drained the oil out of the lines for some reason.  
I have decided to use the sea foam in the fuel tanks on most fill ups.  I hope it will have no effect on the fiberglass tanks.  I also will probably start putting in some mystery oil in the oil compartment.  I have used both of these products in my motorcycle and in the Rotax 582 that I had on the ultralight {which had a fiberglass tank}.
The bird is still grounded until I can find the right radiator hoses for the heating system I have.  Man, don't really need any heat right now in Georgia!!!
:roll:
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