very rich, but lean bogging

[ibanez830]

I've been having tons of trouble with my Lrp.28. Last year I was having a lot of problems with bogging and after reading and help from you guys I found out it was lean. I tried richening everything a bit and it solved the problem, but later on the tuning was off somehow again. So I put the truck away for the winter and over the winter I tore down the engine and sealed it and cleaned everything and re assembled. Today I finally took it out and tried to retune it and it got better. But my problem is, the HSN is very rich, almost more than flush. Theres tons of blue smoke and the temps are barely going over 200F. The LSN is what I was having problems with before as well and I got that better too. But for some reason, when I accelerate I get the lean bogg studdering. The LSN I think is still rich because when I let off the gas it quickly goes into that loaded up idle but I may be wrong, and the HSN can't be too lean because its nearly further then flush.

So I tried narrowing the possibilities down. It should't be lean, as everything including the temps show it is very very rich. I'm sure its a lean bog and not a rich bog. And there shouldn't be an air leak as I sealed everything off.

So, what could be the issue?

(sorry about the long explanation, I know you guys like detailed info)

 

[Scrogg]

Forget the temps, period. You have good instincts, LISTEN to the engine and tune for performance. If you are constantly chasing the tune, it may be time for bearings or a rod. You cannot have any slop in the engine bearings. It causes erratic tuning.
Pull the carb slide out to wide open. Run the LSN all the way in while holding the slide open. Then back out 2 1/4 turns..set the idle gap to 1/2mm, barely visible. Run the HSN back in until it is around 4 turns out. Then run it, with a new plug of course.

 

[ibanez830]

That was another thing, I didn't know what the base settings were for the LSN. I'll try that out though, it could be something with the glow plug too, I don't remember the last time I changed it and its been a while. I'll retune to those specs and start over, if that doesn't work I'll change some parts , I have a new spare motor so I'll take the parts from that.

Thanks

 

[Mickstix]

The LSN I think is still rich because when I let off the gas it quickly goes into that loaded up idle but I may be wrong

I agree with Scrogg, use your instincts and ear.. I think that loaded up idle you mention is actually a LEAN condition from the LSN..

 

[Scrogg]

I agree with Scrogg, use your instincts and ear.. I think that loaded up idle you mention is actually a LEAN condition from the LSN..

Actually it's probably rich. LRP's like a leaner LSN setting than most people realize. The more you richen the LSN, the worse they sound. It's loading up with the excess fuel from the HSN.
Check your carb O-rings. the LRP carb is notorious for a leaky idle screw o-ring. They are a biatch to replace too.

 

[ibanez830]

I only checked the temps a few times just to see, but other than that I was just going by sound. I'm making a presentation in my auto class in school on nitro engines so I'm taking it out, so I'll check everything over and fix/replace whatever needs to be replaced.
I was also thinking before that my LSN could be lean too, causing the HSN needing to be rich or something, but I don't know if that could be possible.

Funny you say LRP's like a leaner LSN, a while ago when I posted here I was told they like to be slightly rich. Either way, when it warms up I'll get it running and try again.


Thanks again

 

[Scrogg]

What I meant by a " leaner setting" is the LSN is screwed in the housing further than most people are used to seeing.

 

[ibanez830]

oooh okay. I put the LSN 2 1/4 turns out and it looked really in, I didn't know if thats how it should of been.
Thanks for clearing that up.
I'm taking the truck out tomorrow and I'll try to tune it. I took out the needles and noticed the LSN had tons of dirt on the o-ring so I cleaned it up and put a little bit of grease on it. I also put in a new glow plug so hopefully that will help solve my problem. The old plug had a bit of red colour on it, don't know what that means. If this doesn't fix the problem I'll take the engine apart and start changing parts.

 

[Scrogg]

Dirt on the LSN means dirt has goten in the engine. I'm afraid you may have worse problems, but good luck! Hope it runs.

 

[olds97_lss]

There's an idle screw o-ring? Huh... hadn't torn either of mine that far apart before. Guess I still learn stuff!

What fuel and nitro content are you running? What plug? What vehicle and pipe/header?

I know my LRP's are very fussy about the pipe/header, fuel nitro content and LSN adjustments.

 

[ibanez830]

I took the engine completely apart during the winter and nothing seemed too different from that brand new one I have that I use for parts (no scoring or major marks). I think there was just dirt on the screw area and some gathered on the outside of the o-ring. Hopefully nothing got in.

I run Byrons 20%
O.S #8 plug (just put in a new one)
Stock header
and an aluminum tuned pipe
On a Savage X 4.6

I got the savage started on Saturday and it seemed to run fine, although I was getting crazy radio interference and I didn't want to create more problems. Probably should get a new radio and failsafe. Time for a Dx3s.

But I think I got it mostly fixed, hopefully nothing got past the LSN O-Ring though, but everything seemed fine. I also did the pinch test and the engine died around 3 seconds and it sounded and performed well. I guess it just needed a new glow plug and some more fiddling.