Broken small-block slide carb

[gandalfnz]

That was the first thing I thought as soon as I saw the pictures--the centrifugal force of the flywheel, it shoots oil everywhere. Rubber shielding lost seal by wearing out due to bearing play. But as mentioned before, it could also be the exhaust manifold gasket. Need to clean it and see at oil leakage with model running but on dyno.
If the engine is now already at its end, many times it is not worthwhile to repair it but to replace it with a new one (I am talking about this kind of inexpensive engines) example this one at definitely affordable prices.

https://www.ebay.de/itm/325672453769?hash=item4bd3974689:g:rIEAAOSw3PFkMDwm&amdata=enc:AQAIAAAA4D7S6l/EjJrMMDC15PKJnRykF3NcO/wiJb6QtzQJD1J882eC7LNnolKonzv+3aewZjV+r9LTVV1Jj0KWHMKeBl9W3dj7TCp9P63ogB3Ts99wPIN5E47Oi36MgH0u5GoLLynY02F0xyTRhHZIiyO6mTqva2xdDylQVe1UzFBArl+xcwfrjKAs2OVVhauwcAY8sz183Vm6B/WeimJuTV9w7K+Sl1fHCdaKCDvJl3CpiU8k/cZjbp8hy1ZlrJUu6gOzxdjCGovt3s3cZcpCeHxiJ9XWDat7rMwrVemED7MubXvk|tkp:Bk9SR-Ti1tKQYg

That engine is one of the best I have tested. Buy it with confidence, it tunes and idles super good.

 

[fstnd]

Sorry for the late answer but thanks so much for your answers and the time you took writing this

I will still try some tests with different exhaust gaskets which are currently taking their time on their way from ali, then I can try putting in another carb, this time from my vintage nitro. Might also try some maintenance (e.g. removing flywheel and see if there is anything I can do with the bearings). If nothing will change, I will indeed just buy a new engine, in which case I'll update this thread with thanks

 

[Sixtysixdeuce]

I've TIG welded these little carburetors, such a repair can be done, but it requires machining afterward. And the heat input can warp the bodies, there's just not much mass to absorb it and some critical features with thin and thick areas around them which are prone to distortion.

Generally not worth your time if you can find a replacement. Definitely not worth paying someone else to do the work if you lack the equipment.

 

[fstnd]

Hello! I have actually received those engines a week ago, but haven't really had the time to do something but today I finally got one of them running in the smartech magic wheel.

I bought 2 engines because the one from this thread is... yes, and the other CEN NX-12 nitro engine from the SP1 GP has NO compression and pinch at all. I don't feel any resistance when turning it with one finger. So the new engines are a "ALPS .12" and a "SMARTECH .15". The alps is another vintage engine because i like my experience with another one I own, and the owner of the smartech told me it was almost like-new and has only been broken in. Indeed it has great compression but not that much pinch. Here they are:

The smartech .15 is fully stock and from what I can see the ALPS has a strange FORCE slide carb with a custom "extension". I also think this smartech .15 is the one that originally came in the "smartech magic wheel monstertruck"?


So today I just got my smartech .15 to run in the smartech winner and it took a few pulls but once it started and shut down, I could easily start it again. Probably today in the evening or tomorrow I will drive it. It already had a great tune the way I got it. I guess this smt engine just likes to run hot because I had it idling for a minute with a rich tune and after that I could barely touch the cooling head with my fingers. Here is the video:

https://www.mediafire.com/file/4jhq3x19z2w6uv3/FirstStart_SMT15.mp4/file

 

[davidb37]

Hello, today I've put in and set all the electronics to my new RC. I confirmed the engine started for 4 seconds but that's it. Guess what? My fourth carb with a problem. They must hate me. Here some pics:View attachment 166721View attachment 166722View attachment 166723View attachment 166724View attachment 166725I know I know, the throttle setup is awesome, but please help. Is there a cheap replacement carb? If there is any way to repair this massive crack in the old carb please tell me.

This crack was already there before I bought it. But when I screwed it in, which didn't even need any force, it broke even further.

Total diameter of the carb where airfilter is hooked up: 11mm
Total diameter of the other side of the carb that goes into the engine:i guess 10mm(hard time measuring due to crack)

I'm talking about the diameter of the whole, not the hole

View attachment 166726

Looks like you're over tightening pinch Bolt/ carburetor lock by about 100 ft lb too much?? Either that or your crankshaft is coming up into the carburetor bore, however I've never seen that happen. Try tightening the new one with just two fingers your index and your thumb. Does not need to be tighter than that. About 12-in pounds. Hope this helps