Does anyone have this size motor they would be willing to sell? It's for a new project.

Thanks,
Doug

Hi,

Check out the thread "Don't forget the Echo.." for info on this engine. The engine you want is an older 23.6cc from the mid to late '90s. They have bigger transfer ports and make more power.

Good luck with your hunting. I found mine in the junk pile of a repair shop. I've modified it, but it turns an APC 16 x 8 prop over 8000 rpm's at 4000' and 80 degrees.

AV8TOR

I found one at a pawn shop and they were asking $150 for it. I told the owner that was a little steep and he said he would sell it for $120. Possibly.

There's one on eBay and the current bid is $100 plus $30 for shipping.

I'd really like to find a "broken" one at one of my favorite saw shops. Over $100 seems too much for a used weed trimmer.

Is there really that much difference between the 21, 23, and 25cc motors weight and power wise? Keith mentioned that the only difference between the 21 and 23.6cc motors is the piston/cylinder. My 21cc has 2 head bolts and 3 pullstarter bolts. Pics I've seen of the 23cc motor show 4 head bolts and 4 case bolts. If not, I could just order the piston/rings/cylinder and put in on my other 21cc block/crank.

Doug

Actually, there is a performance difference. The 21 and/or the 25 will certainly work, but the older 23.6cc engine is the best. This is because of the better porting on the older 23.6 cylinder. The one I'm currently running is the 23.6cc stroker that Keith mentioned. I made it out of a 25cc crankshaft and a 23.6cc cylinder, piston, and crankcase. I had to make a spacer to raise the cylinder to make up for the increased stroke. I also ported it and modified the head as advised by Keith, and it runs great! There is a thread here about a guy who just put together a Funtana with a Kioritz, and I think he used a 21cc. You might look into that thread.

Good luck,
AV8TOR

Thanks as8tor,

I'll have to look at that Katana(Funtana) thread.

In the "don't forget Echo" thread, post # 9, Keith states "I forgot to mention that the only difference between the 21cc echo and the 23.6cc echo is the piston and cylinder." That is what I was referring to, considering the porting is mainly in the cylinder walls.

Why did you put a spacer into your 23.6+cc motor? Again in the "don't forger echo" thread, again post #9, Keith mentions recutting the piston crown. I'm assuming you put a spacer to keep the piston from hitting the top of the head. By putting in this spacer you are lowering your compression. Recrowning would also solve the clearance problem but would leave you with a higher compression ratio(more power), wouldn't it?

Doug,
I hope AV8ATOR and you don't mind me butting in, but he said that he had to raise the cylinder (to clear the piston crown by the correct amount), because of the increased stroke on the 25cc crank, (I don't think Keith was using that crank).

Because of the increased displacement, he automatically raised his compression ratio, ( the combustion chamber volume would remain approx. the same and the cylinder volume would increase).

The crankcase compression would remain (approx.) the same, ( the increased stroke effectively cancelling out the raised cylinder).

Inlet port duration could possibly be changed by a tiny amount, ( decreased? ) and as he said he did the other port timing to Keiths' specifications

Anyway, seems it works well so all this is academic really.

I said somewhere before that I have an trimmer which may have one of these engines, - (still used as a trimmer), but one day I'll have a look ---- .

As always, I could be wrong, and if you think so, let me know why.

HI,

Yes, that's exactly right. I cut the squish band out of the head, and installed the longer stroke 25cc crank. I then had to raise the cylinder to accomodate the longer stroke. I sized the spacer so that I had the deck clearance, (piston to head clearance) of .015" that I wanted. This gave me the most compression possible. I then ported the ports to get the port timing optimal. A bigger carb and a free flowing exhaust, and I was done. I also used CH electronic ignition for optimal timing, lighter weight, and easier starts. I get about 8200 rpm's on an APC 16 x 8 prop here at 4200' at 90 degrees, (would probably go around 8800 or so at sea level). Flies the hell out of my custom built 9.5 lb. plane, "The Phoenix"!!

Good luck,
AV8TOR

Doug,
I have a couple of these engines. They do not come from weedeaters, but from gas powered drills. One I have started to convert by milling off the bottom of the cylinder and turning the top of the piston to raise the compression. The other one is still as it came from the drill. The piston looks very good and looks to have very little time on the engine. If you are interested, email me direct. Dean

[email protected]

Dean,

I stopped by my favorite saw shop and was given a SRM-2400 trimmer head. If I need another, I'll e-mail you.

4.5# as pictured.

Doug

The 23.6cc is a rare find. Why not just start with the much more popular 25.4cc instead. Echo puts this engine in just about every garden tool and cocktail mixer they make these days. Whatever porting advantage the 25.4cc may not have is adequately made up by the added cc's.

I have an Echo 25.4cc converted to CH ignition, and it has the power of between G23 and G26 - just as I'd expect.

Hi all, I have 3 Echos that I am currently using. One is a blower and is marked PB 1000, no displacement given, the other two are weed trimmers, one marked GT 1100 and no displacement given. The other one is marked GT 2400 and has on it 23.6cc. What would the displacement of the first two be? Seem bigger than 10 and 11cc. One day all 3 may find themselves on an airplane each.
Charlie W5RA