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UMS Engines - any experience?

Old 02-07-2020, 08:59 PM
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drorso
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Default UMS Engines - any experience?

Hi,

I'm thinking of installing a UMS 7-90 in my TopRC Zero. Anyone has experience with this engine?
Old 02-08-2020, 04:00 PM
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rgburrill
 
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Hey, it's Horizon Hobby. How can you go wrong?

Just noticed my info shows Trumbull, CT. Haven't lived there in 8 years. I've got to get that updated to Dallas.

Last edited by rgburrill; 02-08-2020 at 04:03 PM.
Old 02-10-2020, 04:56 AM
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maddog-RCU
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Horizon Hobby doesn't carry UMS engines.
Old 02-10-2020, 07:57 AM
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Lol
They never did. Horizon entered into a deal with ums to sell the design Seidel lost to the Indian manufacturer.
They got burned by ums. Just like Seidel did.
UMS is now retailing the " updated" design.
The new ones look superior to the machined billet second generation. And they are very inexpensive compared to other similar engines.

The original Seidel has a beautiful raw bell casting similar to the Moki casting. Pretty engine....
Old 02-10-2020, 11:25 AM
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My bad
Old 02-10-2020, 01:49 PM
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BobH
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From what I've leaned from UMS the engines they made were by "students". Their production is part of their graduate course. So there's that. I have the 770 that needed a better carb. The original one wasn't so good.
I also have a UMS 160 gas that runs pretty well. So I don't if their manufacturing is else where or not?
Old 02-11-2020, 06:20 AM
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Originally Posted by BobH View Post
From what I've leaned from UMS the engines they made were by "students". Their production is part of their graduate course. So there's that. I have the 770 that needed a better carb. The original one wasn't so good.
I also have a UMS 160 gas that runs pretty well. So I don't if their manufacturing is else where or not?
I was under the impression there was a single facility. They have been around a long time. I did some cursory digging after speaking with an industry insider who was pretty forthcoming
I have one with the early carb and it runs good for me.
I had a 7-35 Evo version also. I was happy with it too.
The power to weight ratio is a little better than the os and Saito radials. Plus they don't look like a single repeated on a common crankcase.
I love em all though, got a nice static display of them to stare at. And some to fly!

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Old 02-11-2020, 09:40 AM
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They are beautiful engines but way out of my price range. I will still to single cylinder engines.
Old 02-11-2020, 10:47 AM
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Originally Posted by FlyerInOKC View Post
They are beautiful engines but way out of my price range. I will still to single cylinder engines.
Lol
Outta my price range too. Been a lot of wheeling and dealing to build a collection.Have met a lot of nice people to hand cash over to though, and a couple real stinkers!

Old 02-11-2020, 07:39 PM
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I think it is or was a single facility. Its a school of some sort that's either under contract or run by the Govt.
I believe it's for training students. My guess is that they bought the rights from Sidel and then produced the engines at the training school.
I don't know if that's how they are still being made now or not.
Old 02-12-2020, 04:42 PM
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Originally Posted by BobH View Post
I think it is or was a single facility. Its a school of some sort that's either under contract or run by the Govt.
I believe it's for training students. My guess is that they bought the rights from Sidel and then produced the engines at the training school.
I don't know if that's how they are still being made now or not.
That chain of events would be similar to the Moki Motor history. Cool stuff!
Old 02-15-2020, 06:09 AM
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I have had a few of the Evolution 7-77 and one 7-90. I have had Great success with the 7-77 engines I have one in a Corsair and one in a Zero both planes are above 30lbs. Scale take off but once up and make a circuit they move pretty good. I have about 10-12hrs run time on the Zero. After a day of flying I clear the engine with Marvel mystery oil. Occasionally I have to check the valves for correct lash "every 2-3hrs run time". I do run a Glow system " Sonic Tronic" that will come on at idle . Just makes me more confident of NO dead stick landings. Other than that they run STRONG.
I recently bought the 7-90 I have run it on a bench to do a general break in but have not put it in a plane yet. I am waiting for the TopRC Corsair for that.
Old 02-15-2020, 06:45 AM
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Default 770

Originally Posted by TimD. View Post
I have had a few of the Evolution 7-77 and one 7-90. I have had Great success with the 7-77 engines I have one in a Corsair and one in a Zero both planes are above 30lbs. Scale take off but once up and make a circuit they move pretty good. I have about 10-12hrs run time on the Zero. After a day of flying I clear the engine with Marvel mystery oil. Occasionally I have to check the valves for correct lash "every 2-3hrs run time". I do run a Glow system " Sonic Tronic" that will come on at idle . Just makes me more confident of NO dead stick landings. Other than that they run STRONG.
I recently bought the 7-90 I have run it on a bench to do a general break in but have not put it in a plane yet. I am waiting for the TopRC Corsair for that.
are you running the stock carb with the 770? I couldn't get mine to run well with the stock one.
Old 02-15-2020, 08:44 AM
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TimD.
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Originally Posted by BobH View Post
are you running the stock carb with the 770? I couldn't get mine to run well with the stock one.
NO I use an OS carb. Mine were the first ones out of production that would not feed enough fuel to the engine. I hear they upgraded the carb to work as the OS ones in the newer ones.
Old 02-15-2020, 08:49 AM
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Thanks for the reply. I bought an OS carb for mine too but I havent installed it yet. I removed the engine from the plane it was in.
Old 02-15-2020, 10:04 AM
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Originally Posted by TimD. View Post
NO I use an OS carb. Mine were the first ones out of production that would not feed enough fuel to the engine. I hear they upgraded the carb to work as the OS ones in the newer ones.
QUOTE
Which OS carb please?
Part number ?
What is the improvement over the OEM carb?
Are intake mods or mounting/linkage issues worth the upgrade hassle?
I have not had good success flying a 34 lb pt17 with my factory 7-77 . If yours is flying a high wing loaded 30 lb plus single seat fighter I am definitely not getting all the motor has to offer.
Thanks!
Thanks
Old 02-15-2020, 02:05 PM
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TimD.
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carb = https://www.towerhobbies.com/cgi-bin...p?I=LXCA62&P=7

I had to make an adapter from carb to the engine. I have a small metal lathe so no biggie. The Os carb has a slit cut for idle positions and it will deliver more fuel to the engine so you can get it to run at a fuel rich setting at full power. The stock carbs on the early versions would not deliver enough fuel to the engine. No other mods needed.Again I heard they redesigned the carb to an identical version of the OS a year or two ago , so the newer engines do not need any upgrades.

I run 9% oil and 10% nitro. I buy a gallon of methanol on ebay for like $20 and a gal of Cool power 20% nitro . combine the two, into two gallons= 10% nitro and 9% oil
Old 02-15-2020, 03:55 PM
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Thanks Tim
Sounds like a plan for me may be to buy the ums upgrade carb. I can't make the intake adapter and sounds like they have done it for the upgrade carb.
Do u feel the upgrade gives the motor more power as if starving for fuel with the OEM carb?
The starting and running charistics of my motor are very good
i run it on 10% methanol/niitro 10% syn redlne.
it idles, transitions and runs full tilt without a glo driver.

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