LRP 28S3 engine bearings...

Well, got the new boca ceramics installed... still hear air coming out of the front pretty bad... Guessing that's normal.

However, when I tore the engine apart, I noticed that all 4 backplate screws weren't even finger tight. I didn't see any signs of liquid leaking out, but when looking at the seal perimeter, it looked like air/dirt was being sucked in. So, that may have been my source of aggravation.

Since I spent decent money on new bearings, and it's a known issue that LRP's use not so good ones, I figured I'd install the new ones anyway. I finished cleaning every nook/cranny looking for cracks or deformities only to find none. So, I polished the outside of the sleave up with a dremel, felt and rubbing compound, cleaned it (shiny...), lubed it up, RTV'd the carb/bp and threw it back together. Should have buffed up the back of the crank, but I was tired. I was monkeying with it around 3am and installed it this morning after I got up. Will probably give it a run tomorrow to see if whatever I did helped.

On a side note, both of the old front and rear bearings in my hand showed a lot of inner race slop. More than I'd proffer to depend on.

I've never bought ceramic bearings before and boca noted that you should leave the seals on the front bearing and take only the inner seal off the rear bearing. I wasn't sure how tight to honk down the flywheel nut in fear of putting too much side load on the ceramic bearings, so hopefully I have it tight enough and not too tight. Time will tell...

Ran my rig and it still runs like crap. I know there are no air leaks and it seems relatively responsive to tune, but it seems that I have to run it at least 1.5-2 turns rich beyond factory to get it to run anywhere near right. Even then I get the indicative high idle after a high speed pass and the occasional lean bog if I gun the throttle. The power is lacking, except for the occasional half second that it sounds like it's running right and temps are average above 250F.

Did I just get a full on defective LRP?!?!? Very reminiscent of the axial paper weight I bought many years ago...

I'll be hitting ebay next to see if I can find an alternate carb for it. That's my only guess at this point. Have tried multiple pipes, changed plugs, sealed everything, new ceramic bearings, fresh fuel, different fuel tank and new lines... Still, runs like ass.

My one day off and I spend it with an engine that won't run right and another that has a OWB that slips like crazy... waiting for a replacement for that to show up in the mail. Very frustrating day. If I wanted to be this annoyed, I'd have skipped the vacation day and went to work!

If anyone else has any suggestions, let's hear them!

Maybe this will make ya feel a tad better olds. I've talked a lot about that RC10 I have that I could never get to run right. After everything I learned on here, I figured a good cleaning and sealing would do the trick. Tore it down, yodda, yodda. All good. Got to the carb, let it soak in fuel, removed needles, blew out all the passages, everything looked fine, reassembled and went to it. It just would not run right. Had a pro .15 laying around. Figured, what the heck, I'll try the trx carb on the AE engine. Same displacements, it can't hurt. Problem solved. Engine runs great. I've looked the AE carb over with a magnifying glass. No cracks, no clogs, boot's fine, tight needles, smooth action. Can't find a thing wrong with it. So maybe your carb has the same invisible problem as this AE carb does. Sure sounds like you covered every other possibility.

I had started another thread asking if anyone knows of drop in carbs that work for the LRP28S3. As that is my guess as well. Since no one posts dimensions of things online (except for a few here and there), I'll wait until someone hopefully responds. In the meantime, I tore it down again, cleaned everything, resealed it and re-lubed the o-rings (which looked fine). It's now curing on my bench.

I also switched back to the stock tank with the uni-flow mod... figured I'd start with as few variables as possible and work my way back up while I wait for carb info.

I know this is an old thread, but it's mine and I'm still fighting with this engine. If I had remembered this thread, I probably would have just removed the engine and got a new one, considering it's been 6 years and the engine is still flaky. Guess I have a hard time giving up on an LRP...

Tried the 454 carb, ran better, but still flaky. I'm trying a lowered stock tank mod to help with the HTL issue as well.

The symptoms are indicative of a bad tune. Won't idle well without stalling, sounds fat half the time and lean the other half. Today with the new 454 installed is the best it's ran so far. I tuned the carb per Losi's manual (2.5 turns out from closed on both needles), but it was waaaaaay too lean. It's probably closer to 4 turns out for both at this point. Temps seem fairly stable, 230-260 range. Power is decent through the RPM range with an occasional rich bog in the middle. The only real issues that remain are the inability to idle for long without stalling and the high RPM whine/lean sound after a short WOT run. If I blip the throttle a bit after a WOT run, the engine calms down right away, but if I jsut let off the gas and coast, the high rpm/lean sound lasts for a few seconds.

I want to richen the LSN more, but then it bogs excessively off the line after a few seconds of idle and likes to die. As it is, the idle screw doesn't help things much.

Just frustrating... I'm 99% sure I'm going to pull the LRP out of a buggy I never drive and swap them. I know it ran good, it was just the oldest LRP I had with the most fuel through it. I put it into a buggy that I knew I wouldn't drive much and just wanted something reliable in it for the few occasions I took it off the shelf.

Ya know... I'm just curious if you have a goofy air leak somewhere. I mean something stupid like a hairline crack somewhere. Or a minor machining flaw. Something utterly foolish, ya know?

Yeah, I was thinking something similar. So, when I ran it, I ran in a dustY environment to try and make it easier to see a leak somewhere.

I'm probably going to pull the lrp off my buggy and swap it with the one in my savage just to be able to hopefully run the thing. When I do that, I'll go over the problem engine very closely to see if I can figure out anything.