new motor wont start...

[ausher]

Lrp z.28.... just loads up with fuel and locks up... I pull the plug to clear out the fuel. Put the plug on the ignitor and it glows bright. I preheated it to 170ish...

A side note.. the exhaust is borrowed. I noticed the header leaks at the motor. ....

 

[Phins Fan]

First - Fix the header issue. Trying to break in/tune a rig with an airleak is nearly impossible. 2nd - when you go to start it try doing so with the glowplug loosened a little bit to relieve some of the tight pressures associated with a new engine. Once running resnug the plug. Also what kind of temp is it where you are? If the air is real cold it will make it more difficult to start/break in a new rig.

 

[ausher]

When I noticed the leak I stopped and put it up. I'm going to wait till my exhaust arrives. I got it up to about 170*f

 

[WinnersCircle]

Lrp z.28.... just loads up with fuel and locks up... I pull the plug to clear out the fuel. Put the plug on the ignitor and it glows bright. I preheated it to 170ish...

A side note.. the exhaust is borrowed. I noticed the header leaks at the motor. ....

On a new motor the key to getting it running is preheating the engine. I use a monokote gun on my engines but a good hair drier will work too. Also, you may need to preheat the engine for some time in the future because new engines are tight and heating them is the only way to get them to turn over without locking up at TDC.

Heat the cylinder head area because that is where the binding is taking place.

Lee

 

[2revo1maxx]

He already said he's pre-heating the engine.

If it's loading up with fuel you need to make sure the idle gap isn't too big and start slowly leaning the lsn until it starts. I would lean it 1/2 turn right off the bat then see if it starts. Remember where it was set at in case you need to richen it back up.

 

[ausher]

It started. I loosened the plug and leaned it a 1/4 turn. Thanks. The idle gap is about 1 mm.

 

[ausher]

Grrrr. Started just fine last night when I loosened plug and leaned it out. I didn't even preheat it.

Today I preheated it to 170ish and took forever to start. It finally did and idled fine. Went to Richin it and it died.... went to start it up and I pulled the cord out of the pull start

By the way I started it inside at a room temp of 70ish. Had a sock on the head. My plan was to take it outside after it started.

 

[frickenjoey]

Yeah they can be a pain to start for the first time.... but looks like you are getting it under control...just be sure to try to keep the temps up and drop it to BDC when you shut 'r down.
[ame="http://www.youtube.com/watch?v=G-tCIRJH9p0"]sling blade - YouTube[/ame]

 

[ausher]

yea sorta getting it under control. fixed the pull start (pita!) seems like if i preheat it it wont start easily. if i start it at room temp (70ish) it starts right up.....

so far i let it idle for about 3 min at around 180-210deg f. I'll do 4 or 5 tanks like that then put around 1\2 throttle . dunno where i read it, but it seems like a good method.......

 

[frickenjoey]

From what I have seen the heat cycle method works best. I have broken in around 25-30 new engines and the ones I did the idle on the box method have always had the shortest life. Could be coincidence but heat cycle it pretty tried and proven and what I have been using for the last ten years. We have a sticky to the method most of us use.
Heat Cycle Method Sticky

 

[ausher]

OK. I'll try that. I only fired it up twice so far indoors and let it.idle. its In the 30's outside spill wrap the head in foil hopefully it will keep it around 200°f

 

[2revo1maxx]

The best thing is to make sure it hits 200° while running rich. Those 2 things are not easy to achieve, especially in cold weather..........and don't be afraid to keep it running throughout the entire process if you can maintain the rich 200° conditions. The heat cycle method does work if you're in a hurry, but you're basically forcing the engine to break-in.

https://www.rcnitrotalk.com/forum/showthread.php?t=101875&highlight=heat+cycle

 

[ausher]

So many break in methods. Everyone says their way works best... why are these little two strokes so picky? I never had to break in a weed eater. Just start it up and go wot.

I'll do the break in method that's the fastest. Last method I used was Traxxas and that motor is still fine after 10 years.

 

[Snook Man]

No piston rings and a tapered sleeve in our little nitro engines. Wear of the piston or sleeve results in less compression and more blow by.

With ringed pistons the ring can expand (to a certain point) as it wears to help seal the compression.
You should break-in a weed eater engine also…

 

[ausher]

So it's 20°f out. Covered head in foil. Got it so rich to the point it barely stays running and the temp jumps up to 260° so I take foil off. When it dies I take it inside immediately. I don't think I can run it any richer. I'm making laps down the street at 1/8-1/4 throttle. This thing has more throttle than the 2.5 at full throttle... how can I.keep the temp down? Any richer.it dies...

 

[2revo1maxx]

Richer hsn, leaner lsn. I don't think it should be hitting 260° on a 20° day.

 

[Snook Man]

Just partially cover the cooling head. You will have to adjust the coverage of the head with the aluminum foil to regulate the temps.

 

[ausher]

Well I think I found a sweet spot to keep it about 200°f. Got 1 tank through. Running rich enough to leave plenty of smoke. And keep it running.
Soon as it hit 260° I richend it up so it wasn't more than 30 sec. Is make a pass and check temp every time.
Thanks for the tips!

 

[2revo1maxx]

It should still be around 200° on a 20° day with the head fully covered. Just the air and fuel coming into the carb should be enough to keep temps in check.

 

[ausher]

using a baby sock kept the temp more consistant than aluminum foil. got about a half hour of run time and manage to keep temps at 200ish for 29 minutes of the time (estimate) when it wasn't running i quickly took it inside and put piston at bdc. factory[ setting is 3.75 turns out on both my settings were 4 out on lsn and 5 out on hsn.