Today's Message Index:
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1. 05:07 PM - 912ul Sticking Valves and Carburetor questions. (pperrynas)
2. 05:49 PM - 914 TCU seems dead (Kevin Klinefelter)
3. 10:19 PM - Re: 912ul Sticking Valves and Carburetor questions. (Roger Lee)
Message 1
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| Subject: | 912ul Sticking Valves and Carburetor questions. |
I have a KFIV with 912ul (I'm not the builder or very mechanically inclined) which
has 104hrs on it. It appears I'm having problems with sticking intake valves
on the number 1 & 2 cylinders. This was determined with the help of a friend
who is an A&P but not familiar with the rotax engines. As far as I know this
was not a problem before I purchased it and didn't notice any problems the first
10-20 hrs I flew it. I changed the oil at 95 hrs and instead of the Valvoline
10w-40 semi-syn auto oil and replaced with Valvoline 10w-40 4 cycle motorcycle
oil as I though this would provide better gear box lubrication. I also started
using 87 octane unleaded with Stabil added. Does anyone think either of
these changes could be causing the problem? I am thinking of going back to 100LL
(maybe its missing the lubrication the lead provides?). As of right now, if
I'm willing to let the engine run extremely rough a few minutes, it will smooth
up and run normally. I added Marvel Mystery oil to the fuel (100:1) and ran
about 20 gal thru so far. Also, I added seafoam oil additive to the oil about
2 hours ago. The question on the carburetor is this: Both carbs have a 3 inch
or so clear tube attached to them right above where the air induction comes in(a
little to the side). When I started the engine without the cowl my friend
said there was fuel spewing from these tubes and indeed after shutting the engine
off they were full of fuel. I would like to know what the purpose of these
are and if this sounds like an indication of a problem (possibly caused by the
sticking valves)? When I changed the oil at 95hrs it had ran about 35 hrs and
oil looked clean (almost new). Also, the engine had recently been serviced
by EAST Troy Aircraft (60hrs) per the previous owner and I have a copy of the
invoice (almost $2000) which included a service bulletin on valve spring retainers/carb
sockets/and overhauled carbs. Sorry, about the length of this post,
but would appreciate the advice from anyone who has a good knowledge of these
engines. !
Thanks,
Paul Perry
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=215187#215187
Message 2
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| Subject: | 914 TCU seems dead |
Hi All,
I first ran my new 914 (Europa) last April and began flight testing. All
was good for 10 hours, then I had to put her in the hanger and go away
to work for 6 months. When I got back a couple weeks ago and started it
up the wastegate servo did not cycle and the tach was dead. I have made
sure that power is getting to the TCU, but it seems dead. I plan to hook
up a computer to it to see if that tells me anything, but I don't really
know what else to do.
Any help appreciated,
Kevin
Message 3
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| Subject: | Re: 912ul Sticking Valves and Carburetor questions. |
pperrynas,
I have some concerns here.
1. At only 104 hrs. I have some doubts about any valve sticking from a factory
delivered engine. What bothers me is how this A&P not knowing anything about the
special care and feeding of a Rotax determined the valves were sticking? Did
the A&P have the Rotax manuals, did he do a pressure differential test or static
pressure test? I might be a little suspicious of my valve spring retainer
job until proven otherwise. The engine may have only 104 hrs., but it sounds
like an older engine to have the valve spring retainers replaced under that SB.
2. This problems seems to have cropped up after someone worked on the valve system
and rebuilt the carbs.
3. It was good that you switched to a motorcycle oil as it has the right additives
for the gearbox that regular car oil does not.
4. Fuel is not your problem. I would quit mixing all these oils and fuel stabilizers
as we don't really know how these mix and what they do combined under high
pressure and temps. Use one thing at a time or find out from the Mfg. if it
is ok to mix certain fluids. Certainly some fluids are ok to mix, but one detracts
from the others properties.
5. Get the carbs balanced and inspected by a trained Rotax person or facility.
This sounds like you have a carb issue and a carb problem needs to be ruled out.
Use someone that has been Rotax trained and for the time being do not use a
regular A&P.
The carbs are the easiest and cheapest item to check first.
Definition of an "MIF"?
Mechanic Induced Failure
Nothing against A&P's with Rotax training, but an untrained A&P can be a problem
all by itself.
--------
Roger Lee
Tucson, Az.
Light Sport Repairman - Maintenance Rated
Rotax Service Center
520-574-1080
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=215211#215211
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