This Echo SRM 3100 is my latest find. Super good compression...may need new crank bearings. Here is 2 photos. The third photo is a strange engine. Carb is on bottom of crankcase! Any comments to what it is? Thanks capt,n P.S. av8tor...did you ever see a Echo like it?

Captain,
It has large transfer passages and a reed block on the bottom of the case. It is a 30.5cc with about the weight of the smaller Echos. It may look cool with the carb sticking out of the top of the cowl.

Dave

I have one of those bottom carb enginesalso, haven't done any thing with it yet..

davewallace: What brand is this 30.5 cc engine? With the carb sticking out the top of cowl, a person could build a ram induction scoop to help force air in! Any other data on this engine Thanks Capt,n? Man... I had to use spell check on this post

Captain,
Your third picture in the beginning of this post will do that if you invert the engine. The carb is on the bottom of the case.

Dave

Well I finally got the Echo 3100 apart. It does have ball bearings=32mm in Dia. The piston is just shy of 36 mm Dia. The Piston, rings and crank assembly weigh 300.7 Grams or about 10.6 OZ. I wonder if a good bearing dealer would have same size and maybe beter quality for less than the cost at a Echo dealer? Any help in that department...would be appreciated. Here is the engine apart. New crank seals for sure also. Thanks Capt,n

I had an engine like the one in the third photo, but I gave it away. I don't remember what it came out of now. I also have an Echo 30cc that looks like yours, and I have one out of a chain saw that has the carb on the bottom with a reed valve like your "mystery motor". Haven't done anything with them yet, but they will make good conversions....

Bearings and seals are more universal than people realize. Engineers design around off the shelf, semi-standard size bearings and seals when possible. Try any good bearing warehouse and they will probably be able to match you up with what you need.

AV8TOR

P.S.... Ram air just doesn't work as well as one would think. I read an article years ago that said the gain was only 1 to 2% power at 150 mph. It will also mess up the calibration of the carb and give you fits. Cold air is the trick for power, with a 1% power gain for every 10 degree drop in inlet air temp. All this is why you see many high performance cars with air scoops pointed to the rear; cold air, not ram air.

AV8TOR

av8tor: You are right about the ram air....thats why I have not messed with that engine. Its kinda heavy...but who knows...maby it will kick up a storm!!! Capt,n

captinjohn
Now that you have it apart what is the weight on the parts needed to fly a plane? Engine without Ign parts would be nice as well!

Years ago I used to work at a John Deere store. They could order almost anything from Deere for bearings. I don't know if it's still that way now.

Eagle Flyer: Thanks for the tip about the bearings. I bet they got a lot of John Deere tractors out in Iowa to harvest all that corn! We came through a part of Iowa...seems like all you could see is corn. I bet you guys that fly RC loose a plane in the core and have a hard time finding it. Best Regards, Capt,n from Michigan...."The water wonderlandn

I had an engine like the third one also,came from a craftsman weedie.muffler is held on by a spring.still have the reed valve and carb but tossed the rest.i get my bearings and seals from (Boca Bearing Company).when you order a lot of them are shaft size,outside diameter,then thickness.for instance an echo 61 twin cyl crank seal would be(15x35x6) in mm.doesnt matter who the manufacturer is because a lot of chainsaws use the same seal no matter what the brand is.The last seal i ordered i called them up and had it in 2 days for a low shipping cost.they also have some ceramic bearings for some applications.

So what does the rest of the engine weigh? Just a few more tidbits........
Got my curiousity up as Santa is bringing a NIB version. But he did send a preview.[8D][sm=teeth_smile.gif]

mikenlapaz: I did not weigh all the parts yet. When I get a chance I will. I do know the flywheel and mag assy are big. I would remove them and run glow/gas or gas with a lite electronic ignition. Capt,n

Capt,n I have 2 of those engines from Echo with the carb on the bottom cover. Have yet to mess with them for the carb sticking out of the "hood" reason. However a pro-stock looking snorkel hood scoop would be way cool. Bearings can be had from any local bearing house. I use Motion Industries here. Also www.sepw.com has Echo as well as other brands. Check their site for price and availability. Have you looked at www.echo-usa.com yet? All parts manuals are there PDF style. I download them as I come across an engine.

Tim