sluggish start

[tbbh-teacher]

Let me start by saying i am not a tunning expert. To be honest i suck at it as of right now. I have a 1/8th scale buggy with an old os engine that has a fresh rebuild. The buggy was really sluggish on start and then picked up after running for a bit. I checked the LSN with the pinch test and set it to 3 seconds. This didnt help anything. I leaned out the HSN thinking maybe i am bogging it with fuel. THe clutch is brand new. Is the spring too tight on the clutch how do i tell what are my options. Thanks for the help.

 

[jon2]

If it is a fresh rebuild then you need to break it in again and having it rich is what you want till you do finish. Don't rush or your engine may suffer.

 

[Bouzouki]

Assuming it's broken in,

The HSN can be to rich or too lean.

In some cases, loosening the clutch spring will help accel..

That is the case with Centax clutches at least.

 

[4u2nv]

If ya dont have a temp gun, get one. It makes tuning ALOT easier. And yes, like Jon said, DONT rush break in. This is a MAJOR step that will insure the life of your mill. All depends on how ya do it. If its broke in, Id suggest setting it to factory specs, and going from there.

 

[tbbh-teacher]

this was the third tank of the break in the first i let idle the second i did just enough to make the wheels role to do figure 8s. I am trying to get a little accel now. And it really wont move until higher rpms. I think the clutch spring is really tight in my opionion. Its an aluminum clutch if that helps anyone at all. Dont think it is the HSN cause it will get some speed after holding the gas for maybe 6 or 7 seconds it picks up and takes off. It really seems like a clutch problem. I am trying to tune without a temp gun and more with sound and looking at the smoke trail. I do have a temp gun but i hae read articles saying dont tune to temp. Tune to sound and looking at the trail and then i will check the temp. Thanks for all the help see what you think of this addition

 

[Plaidfish]

first off you are breaking it in too cold it sounds.....if it's real boggy on the bottom and your not ready to start going WOT to clear it out then you are too cold.......you need to get the temp up to 200-220*F when you break it in....if not the piston is slamming into a cold sleeve and it's beating the sleeve into shape instead of heating it and letting it find it's own shape....if you are not versed in tuning definately use the temp gun to get it to the right temp for break in.......AFTER that's done then you can start tuning for performance...I'd say run at least another 3 tanks of doing 3 second gradual throttle increase til you're at 1/2 throttle...then 2 tanks going 3/4 to WOT.....remember gradually pull the trigger till you get to 1/2 or 3/4 throttle then let it go and apply brakes then do it all over again......that's the quick and easy way to break em in......personally I run about 10 tanks to break in an engine......and like the guys said take your time cause this is what dictates the life span of your engine

 

[tbbh-teacher]

thank you for the advice . however i am not running WOT . Yes it may be too cold to start some half speed runs. This would be the third break in tank. I will take it real easy for a couple more tanks and see if it helps. This is an old model engine from OS is an .21 OS RX max i dont know stock settings but assumed to lsn flush with carb body, HSN 4 out. i have adjusted my idel a little high so it would idle without dying with those settings. I pur it in front of the fence so it wouldnt roll anywere. Thanks again for the help.

 

[Plaidfish]

too rich...lean HSN almost 1 full turn in...LSN is already set if you're getting 3 seconds, BTW that should be 3 seconds till it ...lower idle or you'll start dragging clutch shoes....the temp won't get higher until you start doing some speedier runs too....

 

[tbbh-teacher]

when i go to do speedier runs the sluggish start is what i am getting. I am gonna run the car for another break in tank this afternoon. thanks for all the advice i will let you guys know more specifics like temp and what not. when i idle what should my temp be at. i think there is a way to gauge your lsn by idle temp isnt there. are shoul i just stick with the pinch test? Also the pinch test changes with HSN setting isnt that correct.

 

[Plaidfish]

the HSN won't affect it too much, a lil yes.....you shouldn't care what it idles at unless you want to idle the whole tank.......if you are all loaded up then idleing another tank will make your problem worse......try giving a slow pull on the throttle once or twice and see if it clears out...you sound like it's too rich and your going to load it up more.....break in temp is very important lean it out already...get it to 200 minimum (in that range anyway)...your wasting fuel by idling another tank