Savage 4.6 seems rich and runs hot.

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Scalded-dog

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Location
Nebraska
RC Driving Style
  1. Bashing
Still trying to fine tune my tuning skills.

I have a savage x 4.6 that runs well for the most part. But i think i have something that needs tweeked. I double checked all the mechanical possibilities i could think of and they are solid.
It seems to run well.. blue smoke wheelies no bogging out etc... but!!... When i let it sit and idle for say 20 seconds the carb loads up and if i dont baby the throttle forward it instantly dies. Does this sound like it is running too rich?

I started by setting carb to hpi factory standards.
I have idle set to .8mm via feeler guage (paperclip measured with calipers). Then i set the Hsn and lsn flush. Warmed up engine... leaned out the hsn till it had a lean cut out at full throttle and richened it up about 3 hours. I then monkeyed with the lsn until i got a nice slowish camed out sounding idle... and a pinch test speeds engine up in about 1.5 seconds then kills it in about 1.5 secs later. (Total pinch time approx 3 seconds). When comming in from a full throttle run the idle drops down almost instantly (no hi idle then slow idle at all) The engine is running about 245 to 260 F... (temp was checked with 2 dif temp guns with similar results). And the temp is a lil tiny bit higher than i would like for a fomfort zone.

When at idle on a stand it slobbers a goodly amount of oil on bench.. and if i remove air filter it a little bit of fuel out the top. Glow plug comes out pretty wet when i pull it to put after run oil in.

I am shy to lean it out any further as to not increase the temp more.
Lsn is almost at factory flush setting and even an 1/8 turn more rich wont let it idle at all without trimming the throttle open more. Hsn is about 1 3/4 turned in lean from flush. Idle screw is still set to .8mm and has been untouched.

I followed about every part of tuning guide i could think of. Factory carb.. hsn then lsn. To me it acts like the lsn is slightly on the rich side.. and the hsn is about as lean as i dare go.

Sorry for the rambling .. i just wanted to explain my thought process and the tuning method i am trying to follow.

Am i overlooking something? Maybe just turn idle up a bit? Is the 20 sec idle and load up and slightly hi temps ok? I normally dont let it sit and idle that long unless i get distracted or the truck is upside down waiting to be flipped over. But it sure is a pain when i forget to baby the throttle and it dies mid bash session.

Thanks guys
 
That's normal when it sits an idles at a period of time ,it will load up ,a couple blips
of throttle clears that up!...:D
 
You know your stuff cb no question. Its just odd to me that bliping the throttle instantly kills it and babying it open clears it out when the temps are on the high ish end.
 
The ambient temp and the surface you're running on can make your temps run a lil warmer than a 70° day running on smooth pavement. A gear ratio change could have similar effects. The temps sound around correct to me. I wouldn't be afraid to trim and raise a lil accordingly. As long as your adjustments are made in measured increments, say 1/8 turn at a time or whatever, you can always bring it right back to where you were with no loss. Keep your eye on the temp for sure but get it running right. Tuning for temp alone isnt what I like to do anyways... There is always SOME give and take.
The load up at idle sounds like it might be a bit quicker than what my rigs load up at but they all load up at idle eventually. A little blip is just helping to clear the plug of fuel before you dump a lot of air and fuel with a full on trigger. Again, doesn't seem totally out of line. Just to be sure, this is a 2 needle carb, not 3, correct?
 
You know your stuff cb no question. Its just odd to me that bliping the throttle instantly kills it and babying it open clears it out when the temps are on the high ish end.

To fine tune ,run an get your temps up ,if it seem sluggish ,then the Lsn needs to be adjusted ,perhaps leaner!
It sounds that your not too far off ,sense it only bogs down when you stab the throttle!

LSN needle is the transition from idle to full throttle!...:thumbs-up:
 
If it were me, I'd go a little leaner on the LSN and a little richer on the HSN, then adjust the idle to suit.

All of my rigs can sit and idle for quite a while without stalling on take off. If they sit more than 30 seconds or so, they load up a bit, but a gentle throttle usually gets them going without issue. After a WOT extended pass, then idle, it will high idle for a few seconds then drop down. I try to keep my temps between 220 and 250. I run in grass a lot, which tends to make the engine work a bit harder, so I may richen the HSN a bit depending on the weather. I usually don't have to fiddle with the LSN unless it's a new engine, the weather changed drastically or I'm using different fuel.
 
Good advice guys. I will try that. Leany lsn a tiny bit makes perfect sence. And hsn richer if temps crawl higher that what they are. Ill try when i have time and report back.
 

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