Lonestar

iTrader: (14)

Hi Steve and all motor gurus

I finally tried the pinch method to set up the low-end needle after I got some major maintenance done to the motor... it got me in the ballpark right, although it does seem that 7-8s before stalling (with minor rpm increase) yields a setup a bit on the rich side, so I leaned the bottom a bit in the end.

Here's my Q - what would you do to a mill that is slightly slow to go down back to idle at the end of the straight, but on the other end, that goes down to an idle that's *slightly* too low when you come to a stop in the infield, before it goes back up slightly?

Thanks,
Paul

WingWrecker

iTrader: (6)

Shouldn't it only run for 2-3s before quitting using the pinch method? 7-8s would make it very rich. Anything less than 2-3s would indicate lean.

SteveP

When pinching the fuel line, only two or three seconds of running before the engine stalls is definitely too lean. Perhaps 7-8 seconds may be too much for some engines - maybe 6 -8 seconds would be a better range.

portyansky

iTrader: (54)

Yes, that's correct. But when doing the pinch method, you have to make sure the engine is at running temperature.

houston

iTrader: (96)

try richening the hsn a little paul and your idle gap is too small with over lean lsn more than likely , possibly , maybe , could be .

in arizona the pinch test was yielding about 5-6 sec. before dying out on most novarossi engines at proper tune . it will be different in different places so take everything you read as a ballpark figure and it will get you close .

monty

kodiakbear7070

Ok this is the deal I am trying to just get the motor to run steady but with out high tem I had everything on factory set up except for the idle I had to open it up more. It would start but not stay running so I first tried the high end went counter clockwise about an 1/8th of a turn that didnt work. So I turnned the low end about an 1/8th of a turn It started running but would die. So I continued with the low end small amounts at a time. But my motor temp was climbing up to the 250 range so I would shut it down and put the piston at BDC. So my question is what do I need to do to stabalize my temp.

Lille-bror

Hi.

Sometime the factory settings are too lean.

We must assume that there is no dirt in the fuel system.

You must have a hard time priming the engine.
Try this:
When you turn the engine on the starter, there shall come fuel towards the carburator (slowly) when the throttle is in idle position. If not, try open the throttle to half open position. If the fuel runs towards the carburator now, you will have to turn the LSN out by ½ turn, and try again. If you don't get any fuel towards the carburator with ½ throttle, you will have to turn the HSN ½ or 1 turn out and try again.

Then your engine should fire up and run rich (much blue smoke and sound like a lawnmower – 4 stroke).

Cheers

WingWrecker

iTrader: (6)

Is your engine fully broken in?

kodiakbear7070

no it is not im just trying to get it stable so that i can do the break in as suggested in this guide.

Nu-Moo

Hi all, Steve P and/or Monty... Very interesting reading. I've just finished reading the thread.
I just got a new O.S V spec for my MBX6 that I just finished building, my first REAL nitro set up. But after reading the whole thread I'm a little confused?
My LHS wants to idle it on starterbox for a couple tanks for break in but after reading this Im not too sure about there method now?!
So from what ive read this is how it should be done... Put new engine into MBX6 then put the buggy on the ground(carpark) and 1/4 throttle straight away, quick squeezes, 2-3mins then stop? repeat for 15mins? Then 3-5mins and stop for cool down? so on for up to 30mins? Keeping it fairly rich through out process... then say after about a total of an hour running time then the engine is ready for race tuning? Also use 30% nitro or same fuel that I'll be running?
Does that sound about right? Sorry but all the input has my mind a little confused as its my first real race buggy and engine. Any adjustments then please correct my post as I'll be ready to run engine in once I get the thumbs up or approval from you guys. Thanks a million in advance

tkhoo

iTrader: (45)

What you said is right, but you miss 2 things

1, heat the engine till 90-100C with heat gun everytime before you start the engine
2, BDC the piston everytime you shut the engine off

houston

iTrader: (96)

all the above and make sure engine stays @ 180-220° during the run in process .

Nu-Moo

Thanks guys, I'll try this method out. I'm pretty sure my LHS will think I'm nuts though...
I also forgot to ask, do I set needles at factory settings to start with? Is that a rich enough setting? If not then do I richen it so that engine runs without stalling? Probably repeated questions but I'm just preparing to do things the right way so that I dont ruin my first real performance engine... Anyone with the time to do so(hint hint Monty or Steve) please PM me detailed step by step guide in running in my new O.S V SPEC, would be much much appreciated. I mean what to do with needles if engine stalls or wont run for 2-3mins for me to even try running it in this method? basically everything plus some, Im a little worried I might end up stuck on ideas if anything should go wrong or not go my way. Just taking extra precaution... thanks in advance!

Nu-Moo

All good. Break in went well, didnt stall and so far so good. I was a little over worried perhaps...

WingWrecker

iTrader: (6)

Did you get a full gallon through it already?