If it is new and the plug isn't hot enough the compression can do that, use the extra shim if you don't have it in, if you still breaking it in, just like they said don't plug the pipe, if it's on the box when running, just turn the box off and bump it on the flywheel, and return to BDC and let cool.

Thanks guys. Engine has just over 2 gallons through it now. Was broken in with the run in shim fitted, which I removed after 1 and a bit gallons. The plugs that come out look good. No distortion in the coils that I can see. Coils are nice and silvery, and plugs are slightly damp on the bottom. Stopping engine by flywheel method and occasionly by pinching fuel line to check LSN settings. I have changed back to the standard head for the time being, as the turbo plug count was gettiing a little expensive.
My other 5 Port which is newer (about 1 gallon) and running standard head at this stage rarely blows a plug. Broken in same way, same fuel etc. I might put the turbo head on this engine and see what happens. Cheers

Keep us posted Grizz

Grizz its also possible that your idle gap is off, causing an incorrectly tuned LSN needle and that could be killing your plugs as well. I would reset or check the idle gap as well.

Mr-413bt, I don't think you said how much fuel you have through your engine but... If needles are set correctly you may have a bearing acting up. I had an engine one time that acted similar to yours and the bearing wasn't loose like they get when worn out it just didn't spin good.

When we were starting out racing nitro we killed the engine by plugging the stinger, we went through alot more plugs then. Grizz maybe try some differnt brand plugs.

Rex

hey grizz,

I would definately check your Idle gap and try a different brand of plug I only run novarossi in my GO engines as they semm to last better than any thing else I've tried also give the OS P3 a go they work really well also.

Are you coming down to Hamilton this Sunday if you are I can have a look at it for you then.

Adrian

Cheers guys. Hi Adrian, yep I am all set to go down to Hamilton at this stage.
Will catch up with you down there, thanks.

Here's a vid, the first buggy going through the jump section is my son with a Go 7 port. It was only the second race day on the motor and it was only 225 deg. at the end of 20 minute main. Wrights77 is also in the vid.

http://www.mnnitroseries.com/gunner/WOR%20Rd%205%20.wmv


Rex

Hi Guys
Just want to check that i'm going things ok
Just got my first nitro engined car and bought a go 3 port to go with it. Installed it in the car so the linkages give full movement etc. Have begun break in in accordance to the instructions that came with the engine.
Here's the bit i'm not sure about - i've done 2 tanks on the starter box at idle and on the 3rd tank. Lots of smoke from the exhaust. Takes a lot of gas to get the car moving but once going seems fine but when the gas is let off, the engine continues to rev highly (but not enough to move the car) before slowly idling down in "steps", is this a feature of running the engine rich and therefore nothing to worry about?
Temps get up to 200F on a cold day here!

Just learning so wanted to check as this thread is really informative and you guys seem really helpful, thought you might be able to advise an old time electric racer!

If it takes a little bit to get up to speed it is either way rich or lean on the low speed needle (the screw at the ball link/cup). If it blows gobs of smoke while getting up to speed, it's too rich. The high idle after letting off is from having the idle gap to large and the bottom too rich at the same time. Even with the idle gap big, it's loading up and that's what makes it seems as if it starts to idle OK.

Take off your air filter and look at how much gap the carb has when your radio is at neutral, it should be about .75 mm. I usually use a 1.5mm wrench then judge halfway. ALSO make sure it returns there every time to let off and it does not close off when braking. If the engine won't rev down properly with a gap near described, the tune of the low speed needle is off a good bit, or an air leak. Don't concentrate on an air leak until you have tried to reset the idle and the car accelerates consistently.

Thanks for that

I have left the needles as they came out of the box with the exception of richening the HSN 1turn as instructed for breakin. To me it just feels like the engine is taking a little bit to burn of the excess fuel loading up from running so rich. Does this make sense? I want to understand what is happening so I get it right!

Thanks again

sounds to me like you have the idea. Run a couple more tanks through it like it is just to get it worked in some, then gradually lean the needles back down, using what I stated earlier.

People have a misconception that if it runs high then calms down it's "lean on the bottom" which alot of times isn't true. It can be the case. But if it's so lean that the idle won't come down, it will sound like it's cutting in and out as soon as you give it throttle, not gurgling like it sounds like you have. If it accelerates smooth and crisp with good smoke when you go from a stop to full throttle, it's not to lean on the LSN, this make sense?

The HSN is the main contributer to temp, especially if you go past 1/2 throttle alot.

I don't have a TON of familiarity with these motors inside, but I pit one all the time. From reading here, it also sounds like if you haven't put in the additional shim under the head during break in, you should also try that, and use 30% nitro from any leading brand.

I got my 3 port today looks awesome.

mutley- I stumbled on this in another forum, it's what I was describing but maybe his description will be clearer, this guy knows a helluva lot more than most of us on here, lol.

Here is a quote from one of the greatest engine tuners of all time, Ron Paris:

I would like to address what seems to be the # 1 mistake we encounter in engine tuning:

Carburetor Needle balance:

It has come to our attention some racers are making the mistake of setting the idle speed opening to wide [high idle] and setting the bottom

end too rich!

This will give a false normal idle speed even though the speed is set to high because it “loads up” the engine with excess fuel causing the idle

to be lower than set!

The end result is a very unstable idling engine that surges and may cut out as full throttle is applied because the over rich bottom end can

disguise a too lean TOP end setting!!!

Let’s address this a little more in depth!

Idle speed opining set too wide:

It is possible too set the idle screw adjustment in to far but yet the idle speed is not high!

Even though the air regulation [carb barrel or slide] may be set to a position that would normally equal a vary fast idle, the idle is low because

the low speed mixture adjustment is set so rich that the engine loads up with excess fuel and the engine goes into what’s commonly called a

four cycle idle.

One tell tail sign of this is if after reving up the completely warmed up engine it tends to idle fast for a few seconds then drops to lower idle

speed.

[Here we go again with the written sound effects :-)]

Something like da..da..da..da..da..da..da..da then it drops to da….da….da….da [if it were sheet music it would be like dropping from 8 beats

per measure to 4 beats per measure]

If you start leaning the bottom end a little at a time [then repeat the reving up and idle test] and it takes longer before the idle drops your going

in the right direction!

Eventually as you keep leaning the bottom the idle will stay to high, now it is time to lower the idle to were it belongs by re adjusting the idle

screw!

CAUTION!!!!

Now that you have the idle set correctly the top end may be too lean!!!