flyingagin

I concure. I have a 3000. Sure as heck looks like the same case and a mutated head. Obviously front rotary valve induction just like the 2 stroke. So it must induct into the case. Does it need some kind of extra valves in the back? Like reeds or a disk valve? I would not think it would get any boost like a ys.

1QwkSport2.5r

Who knows? This is the first I've heard of ST ever making a 4-cycle engine, so your guess is as good as mine. I'm very curious about it.

hsukaria

Next thing is the argument of Italian vs. Chinese made on the 4-stroke. One of those subjects that never goes away..

1QwkSport2.5r

This ST 4-stroke would have been made in Italy I'm sure given the timeline. I doubt it was transferred to China.

Bax

My Feedback: (11)

I don't think that engine really ever made it into production. If it did, I don't think any came into North America. We became the SuperTigre distributor and service center in the 1980's, and never saw one of those either in the sales area or come into the service shop.

hsukaria

It might have been an April Fools joke ad like manufacturers sometimes do

1QwkSport2.5r

I figured it was probably a prototype and not a production engine. Mr. Garafoli was very much what seemed like a "2-stroke guy". If he wanted to innovate into 4-cycle, I doubt he would have built the engine the way it was built in that photo.

1QwkSport2.5r

It (ST S3000 4T) was a prototype presented at the Nurenburg toy fair in 1985. It never went into production.

jeffie8696

I tested my Super Tigre 61G the other day and was pleasantly surprised at how well it ran. I recently found the oring on the backplate damaged and repaired it. I wish they could bring back the line............ BAX

FlyerInOKC

My Feedback: (6)

What does the rest of the ad look like? I would love to see the whole thing.

Walther

My Feedback: (1)

I will see if I can get that for you.



Tom

FlyerInOKC

My Feedback: (6)

Thanks Tom!

Walther

My Feedback: (1)

OK here is the ad

FlyerInOKC

My Feedback: (6)

Thank you for the ad!

1QwkSport2.5r

Is that an old RC magazine or maybe great planes catalog or something?

FlyerInOKC

My Feedback: (6)

I was a little curious about that myself. Judging from the yellow edges it must be from 1985.

1QwkSport2.5r

I asked about this engine on the other big RC forum and was told it was basically a prototype and never went into production - I suspect they advertised it and were trying to promote it and didn't find much interest? I couldn't find any other information on the internet about it, so if there are any running examples out there, there probably aren't many if any.

hsukaria

If anybody has one, it would be Earl (earlwb). He has all kinds of crazy engines

spaceworm

Could this be the concept prototype for the Stihl 4 Mix 4S engine? Intake into the case. then pressurized by the down stroke of the piston. Directed by the pipe to the intake valve under that pressure to be inducted to the cylinder top? "Interesting, but strange"
Sincerely, Richard
Como 90

FlyerInOKC

My Feedback: (6)

If you want weird 4 cycles check out the RCV SP series. I have been drooling over them forever.

http://www.westonuk.co.uk/westonuk2_047.htm

1QwkSport2.5r

Anyone got any ideas why an S90K with a new Bowman piston ring would surge at WOT when set rich? It will surge about 200rpm when set anywhere from 1,200rpm rich of peak to totally peaked. Tried an 8oz tank with standard clunk drilled to 1/8" (larger than the ID of the fuel line) and a 16oz tank with an OS sintered clunk and Uniflow setup as well as standard vent setup. Same running behavior with both tanks. The fuel would back up into the vent line when using the Uniflow when decelerating from WOT, but otherwise the engine ran the same. Using 5% nitro 20% oil fuel, McCoy MC59 plug, APC 12x6 prop, and Jett .90 red muffler. The engine peaks a little higher with the Bowman ring (14,100) than it did with the stock ST ring (13,800), but the rest of the engine is the same as before when it ran normally. I have run (9) 8oz tanks of fuel on the new ring - it will hold a lean setting endlessly without sagging, but the ring may not be totally seated yet. I suspect it may just need more runtime.

https://youtu.be/jMaSIhnopF0

hsukaria

I am assuming that you checked all the head and backplate bolts? No leaks in the carb base? Is the head temp not getting to hot?

What is the frequency of the surging?

1QwkSport2.5r

Everything is tight and sealed. It is not overheating. One fellow suggested the ring being suspect - that the ring is over expanding and binding. The truth is an iron ring will not expand more than the piston and liner will. The ring gap of the new ring is .002" and from the correspondence from Frank Bowman is what it should be. I have several engines with his ring in them with the same or tighter ring gaps and they do not behave like this.

The surging frequency is about 200rpm and its every couple seconds. Once you Richen it down to about 1,500rpm off peak, it runs steady but it's audibly rich. I use the 12x6 prop so the engine runs about right in the middle of the tuned range of the pipe which is 13,000-15,000. I would set the top end at about 13,400 with a full tank of fuel.

hsukaria

Do you know if it surges with a stock muffler? Maybe checking that might help narrow it down...

1QwkSport2.5r

I ran the same muffler on the engine with stock ring with no problems whatsoever.