MMGT 3.0 breakin woes

[i_am_ed]

Okay, a follow up to my introduction post:

My first 3 or 4 tanks were exactly per the instructions that came with the truck (Team Associated Mini MGT 3.0). Briefly this is: First two tanks with the HSN screwed out 2¾ turns (stock setting normally is 2½ turns). Third tank at 2½ turns and the fourth tank 2¼ turns.

This seemed to be fine, although I was suspicious that the engine was too hot at times - a water drop on the head was sizzling off within a second. However, the engine wasn't actually running long enough at any one time to stay really hot. The issue was, the engine just wouldn't run over half throttle. It would accelerate with plenty of blue smoke but anything above half throttle - bam, stalled.

Here's a video of it.

Sorry about the poor quality, was using my phone.

Some helpful people at aeforums.co.uk suggested it sound like a lean stall, simply as if it was running out of fuel. Running the HSN screwed out by 3¼-3½ turns is much better. It's not tuned perfectly by any means, but now I can get to WOT without a stall I think the LSN needs to be leaned a touch, but that's by-the-by.

But, at times I think the engine has got really hot... hot enough to make the WD40 residue smoke. Also, when the engine was new there was decent pinch, but now if I turn the engine with the plug out there's just a hint of a pop as the piston goes through TDC. Is that a sign of undue wear? There seems to be decent compression with the plug screwed in, however. I also took the head off to have a look - there's a small amount of pitting on it and it's a mid range golden colour whilst the piston is a little bit darker.

What do you think? Has the engine had too much of a hard time during the break-in? Is the fact that the HSN needs to be a full turn richer than the stock settings a sign of a problem? I've taken the HSN assembly apart to clean it but I couldn't find any debris lurking inside.

I'd be interested in your opinions, or am I getting worked up over nothing - I should just tune it up wherever the engine wants the needles to be and ignore the stock settings?

Ta

 

[Glass Bullet]

I'm no expert by any means, but if you have to screw out from stock to have it run good, then there is probably something wrong. During those first 4 tanks, how did you fun. As in letting it idle or going all out or what?

 

[i_am_ed]

I'm no expert by any means, but if you have to screw out from stock to have it run good, then there is probably something wrong. During those first 4 tanks, how did you fun. As in letting it idle or going all out or what?

Thanks for you message. I was trying to get it up to temperature because I'd read about the heat cycle break-in method. I didn't idle it, just cruised around with blips of power.

During the first few tanks I didn't realise there was a consistent problem with it stalling when over half throttle, and even when I did realise there was something going on I just took it to be part of the break in process that would sort itself out.

There were definitely times when it seemed to get too hot though.

Incidentally, I always tried to get the engine cool with the piston at BDC.

 

[DuckStang]

Thanks for you message. I was trying to get it up to temperature because I'd read about the heat cycle break-in method. I didn't idle it, just cruised around with blips of power.

During the first few tanks I didn't realise there was a consistent problem with it stalling when over half throttle, and even when I did realise there was something going on I just took it to be part of the break in process that would sort itself out.

There were definitely times when it seemed to get too hot though.

Incidentally, I always tried to get the engine cool with the piston at BDC.

Dude, your HSN is wayyyyy to rich....screw it in 1/4 turn, then see if it gets better.

 

[i_am_ed]

Dude, your HSN is wayyyyy to rich....screw it in 1/4 turn, then see if it gets better.

Do you mean from the video? Because screwing it in didn't change anything Only when I screwed it out did it get better. But I'll try as you suggest, ta

 

[olds97_lss]

After watching the vid, your far too lean on the HSN.

How many tanks have you run through it by now? I know you noted what you did for tanks 1-4, but didn't really elaborate any further where you are at now.

I have yet to have an engine start running "well" until I hit about 10 tanks or so through it. When I break an engine in, I heat cycle it up to about tank 6, then start gently tuning for better performance. Through all tanks, I tune to get the temps up as close to 200F as I can without over leaning. Usually around tank 6, the engines start to calm down a bit and accept tuning adjustments better. By 1/2-3/4 gallon, they are usually fully seated and are going to act/tune the same until they wear out. At least that's been my experience.

I've broken in probably 18 engines or so that were mine and a few that were other peoples. None of them were what you would call "fun". But it's a necessity with these engines or you burn them up really early in life.