choppy engine

[CoreLEx]

I tried running my buggy today with my new 20% fuel, but it didn't perform as good as before, ie, it frequently died, so I went ahead with tuning the engine (picco .26). Now the engine sounds extremely choppy and seems to lack power especially when speeding up from idle.

I don't know if this has much to do with it, but the humidity outside has been officially announced as being 100%. Lovely day...

Any thoughts?

btw, for the LSN, how does turning it clockwise/counter affect the engine? At the moment, I'm just turning it until it feels right, and don't really know what's going on.

thanks.

 

[nitro dave]

Try resetting the needles back to factory specs, then tune from there. Get the HSN tuned properly first, then if you need to adjust the LSN. The HSN is the most important needle as it adjusts the mixture of fuel and air for the engine. The LSN will affect your initial take of or lack there of. Do a quick search on "LSN pinch test" and you will find several ideas for testing if you are in the right ball park for settings.

 

[highflyin]

Turning the lsn clockwise will make the engine leaner. Counter clockwise will make the engine run richer. the leaner it is the faster it will be but if you go to fast it will overheat.

 

[nitro dave]

Originally posted by highflyin
Turning the lsn clockwise will make the engine leaner. Counter clockwise will make the engine run richer. the leaner it is the faster it will be but if you go to fast it will overheat.

I think you are referring to the HSN not the LSN.

 

[CoreLEx]

I'll try that nitrodave. Does an engine's tuning really get this bad after switching fuel percentages? The engine didn't even idle when I first fired it up!!

 

[nitro dave]

There are a lot of things that affect tuning. One of them being nitro percentanges. Humidity and temperature also affect tuning.
You basically need to tune everytime you run.

one more thing
I would check your glow plug while you are at it. A fouled up plug will cause the engine to run crappy.

 

[CoreLEx]

well, I went outside again and tried retuning the engine. This time round the choppiness was still there but to a much lesser extent. Giving the engine a few WOTs while holding the wing up seemed to help a bit in clearing its lungs.

I'll run it with a fresh glow plug tomorrow morning and hopefully that will help. Would've tried it right now, but I'm starting to get dirty looks from the neighbors :egad: :egad:

 

[imnotsure]

The 100% humidity thing has a big effect on tuning in my area. You can either run with it rich and save your engine life span or lean it out until it has all the power you need and it will run hot. That’s why you need a temp gauge I tune my .26 by temp if it runs like crap on the humid days o well my engine will last longer. When you find the sweet spot and the dry air moves in lookout, this thing will rock. I’m not the best in the tunning dept. but the picco has made me better at it. I did what nitro said the only difference is I took the needles all the way out and lubed the orings made sure there was no trash in there and reset them. Started with the hsn to get it to run then adjusted it from there. The picco for some reason has a tendency to need the needles reset every once in awhile. I will make a difference after doing the reset.

 

[007kel]

I've got the picco 26 non pullstart on my inferno. I'm not having the best of luck with this. I tried to reset my needles, but the instructions say to put the lsn 10.5-11 turns from close. Does this sound right? I did this and the lsn sticks out about a couple of mm's from flush.

 

[CoreLEx]

I'm no expert in nitro's, but I start tuning the the lsn from 1.5 turns out from flush.

If you carry on getting problems with your low end speed and nothing seems to work, you might want to try what other people have tried, and that is getting the black lsn (as opposed to the silver, pointed one on the newer models).

 

[imnotsure]

The factory settings didn’t work for me the engine would not even start. I had to put my LSN below flush to even get it to start.and tuned the HSN for rich setting then tuned LSN again so it would not bog at takeoff. Is this the right way .:shrug: but it worked.

 

[CoreLEx]

This is my second Ofna engine and so far both engines' manuals have had factory needle settings that are way off from what I end up using before tuning! :arrr:

 

[007kel]

Originally posted by CoreLEx
you might want to try what other people have tried, and that is getting the black lsn (as opposed to the silver, pointed one on the newer models).

Really, I've never heard of this. Would anyone know of a part number?

 

[imnotsure]

Originally posted by 007kel


Really, I've never heard of this. Would anyone know of a part number?

i don't know a part # but if do a search on the picco it talks about it .If I rember right this was on the first piccos that hit the market.Some people got a bad ones they sent some people the good one in the box as extra parts.I think they fixed that now.

 

[CoreLEx]

http://pub77.ezboard.com/fofnaracingnitrotalkbackfrm26.showMessage?topicID=46.topic

Despite what the thread says, Ofna have confirmed that the silver needle is indeed the newer one.

 

[007kel]

I just got back from the track tonight with Mjime. I could only get one lap around the track. I couldn't get the picco to settle. It would load up and cut out. Or I would lean out, but the engine would eventually run up to 300 degrees. It's this carb, I can't get the engine to settle for one tank. I'm calling ofna tomorrow. If they don't help me out, I'm taking this engine to the driving range and I'm going to tee it up against my driver.

Anyone know of a substitute carb?

 

[Powerman6766]

Set it back to factory.

I would set it back to factory and run a few tanks so it gets used to the new 20% fuel.Then I would adjust it from there.It may need leaing out.