The Making of N327GM...

Hello, Doug.

I would love to come out there..... but probably not with my work schedule this year. It does sound like a lot of fun!
 
Well, I recieved my temporary registration card from the FAA today. Woo hoo!

I also have received all of my carb parts, so it's time to get it put back together and taken to Olney for the airworthiness inspection.
 
Finally found some time to get back on the gyro.

I got both carbs rebuilt today. All of the O-rings on the various parts were shot, so they all got replaced. I put a new needle jet in each carb, so I now KNOW that both carbs are jetted the same. There was a fair amount of gunk on the main jets, as well.

Hopefully I'll get some time this week to remount the carbs and start doing engine tests again. If I'm lucky, this will solve my problem of having different idling temperatures on the two cylinders.

Also, I joined ROTAX-OWNER.COM.... It was worth the price for me, just for the Bing 64 carb instructions... very detailed on disassembly, inspection, and re-assembly procedures. I highly recommend it.
 
YES - I was made aware of all the goodies available on Rotax-owners.com just under a year ago! The videos to refresh one's memory of various procedures we learned in Rotax school - when you need to actually use them is very much worth the subscription!
Glad you got your carbs cleaned,re-kitted & jetted ... I observed as mine were done last year (& helped with cleaning off of dried-gas-gunk) ... I didn't realize your engine was a used one .... that explains a LOT! ... the carbs are the key!
Looking forward to hearing about - the next steps - taxi trials.
 
Gary- It will be exciting to see your Genesis be the first one to lift off of American soil.....and what a gorgeous build at that!

Stan
 
What's the chances you'll be able to make Mentone this year Gary?
 
Thanks, Stan.

John.... unfortunately, yet again, I won't be able to go to Mentone. I'm starting a new job on July 22nd, and won't be taking any vacations for a while after that.
 
This is good news buddy!!!
Many cannot wait to see her in the air!

Thanks for the tip about Rotax owners, looks like I'll be needing them too.
 
Put the carbs back on and did some testing this morning.... no change on the difference in cylinder temps. One cylinder still running hotter than the other.

It has been suggested to me by PM to not worry too much about the idle temps right now. Just put the prop on it and see how it does with the prop moving air. That's my next step, but can't do that today because I don't have a helper available.

I'm going to work on getting the trailer ready, with a blade rack, tie downs, etc.
 
I'm trying one more thing, just to be sure.

I'm changing out the gaskets between the cylinder head and the intake manifold on the hot cylinder, just in case there is an air leak there.



Here's the new gasket...... should I put any additional sealer or liquid gasket stuff, or should I just put this one in place and tighten it down? I can't find any online instructions for the HKS, and was hoping someone on the forum could chime in with what is normally done in this situation.

 
Try this.

4.14 Intake manifolds reassembly
• Clean and remove oil from contact surface of
cylinder head and intake manifold.
• Place new gasket 􁶃. The seal spreading side is
assembled to manifold side.
• Tighten intake manifold with 2 bolts 􁶄 M8-20 to
2.4 [kgfm] applying LOCTITE 243.

Manuals can be found at http://apsu-hks.com/Services.html
 
Thanks, Jeff.

Where did you find the manual? Your post looks like it is cut off or truncated.

Thanks, Gary
 
Thanks, Jeff.

I have the installation manual and the operations manual, but I missed the service manual that you showed me.

Much appreciated.
 
This is disappointing to us I can only imagine your frustration!

If you still cannot find why the difference at idle I would proceed as PM'ed... to see what the reading are at higher RPM?
 
Yes, John. I'm fairly frustrated right now.

I'm going to do testing with the prop on at higher rpm's and see if that makes everything better..... I really don't see how it could, but it's worth trying before I do anything different. There's a 500 degree difference in EGTs between the two cylinders.... something HAS to be wrong.

Assuming that testing with the prop on confirms that I still have a problem..... I'm not sure what to do. I've changed everything from the air cleaners all the way to the intake ports on the cylinders, and I'm certain that I did the carb rebuilds correctly.

It seems that next steps would be to have an expert look into the engine itself, which probably means an overhaul / rebuild.... I don't know if I want to sink more money into this engine at this point.... I may just start working on installing my Weber 750!!! I'm sure that will only set me back another year.
 
500 degrees is a LOT. On my 582 I get concerned when the temps are off by more than 50 degrees.

I would think that it is a sensor (or wiring) issue. Have you swapped the sensors around to see it the problem follows the sensor or the cylinder?
 
Thanks for the idea, GW. I'll try that just to see, but the CHTs are also off between the two cylinders, so I really expect that one is just that much hotter than the other.
 
Yes, John. I'm fairly frustrated right now.

...

It seems that next steps would be to have an expert look into the engine itself, which probably means an overhaul / rebuild.... I don't know if I want to sink more money into this engine at this point.... I may just start working on installing my Weber 750!!! I'm sure that will only set me back another year.

Gary, good plan, only lets see what your test show at higher RPM.
Then lets see what the pros think?

Together we can figure this out?

PS:
I sure do not wish you to wait a year!!!!
 
Gary let's start off with at the beginning of the day and turn on the EFIS and verify that the EGT and CHT readings are all within a few degrees of each other.

Do a compression check and let us know the readings.

We will start with this.
 
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