Cant get lrp zr 30 to run

[Merc man]

I'm having some trouble with the new motor i put on the savage. Got it pretty much broke in couple weeks ago and went to run it today. I cant make it do anything. It fires up, may idle for a bit then die. Give a little throttle and dies.
Things i have tried is a brand new number 8 glow plug.
I read that some times they have half tank lean isues and if you make a coil with fuel line will help. No better so i put regular length line back on. Tried all new line.
Fuel tank was full.

Any help would be great.
Thanks

 

[NightFlier X4.6]

Have you reset carb back to factory settings

 

[Merc man]

I even tried a different muffler to rule out the impulse.

 

[Merc man]

Yes. Forgot to mention that. I di reset back to factorg settings and start from scratch.

 

[NightFlier X4.6]

Have you looked to see how many shims are under the head?

 

[Merc man]

What are these shims. Every thing is stock still motor wise.

 

[NightFlier X4.6]

If you take the head off you have the cap your glow plug screws into they are on the bottom side of it I've read that around three shims works good. I just built me another nitro out of spare parts haven't tried it yet. Just giving you something that might help.

 

[Merc man]

Would shims matter if i stay with same glow plug number as it came with.

 

[NightFlier X4.6]

What do you mean matter? Do mean would it change anything I don't know. I mean if you tried everything else it's worth the shot.

 

[Merc man]

I was wondering if it could be the fuel tank. Would it work better if fuel came out from the bottom of tank vs having to be drawn from bottom up.

 

[Merc man]

My next thing to try is my fuel tank from traxxas tmax to see if it will run better.
It seemed to run pretty decent for the break in. But the first tank was kinda like this.

 

[Caretaker109]

Stock tank is fine.
I think it is just because of different ambient temperature.

Maybe it has been raining, warmer, or just colder.
Just make sure to use the correct plug. Maybe a warmer plug will fix it .

 

[NightFlier X4.6]

The port in the top of your tank should go to your exhaust pipe and the bottom to the carb.

 

[NightFlier X4.6]

Yes stock tank should be fine

 

[Caretaker109]

Did you use after run oil after break in?
Takes some time to burn that...

 

[Merc man]

Yes i used wd 40 for after run oil. When i first fired it up i had it running for about 3 mins no problem. Had cylinder temp up to 165 by the glow plug and then it cut out while doing figure 8s and it wouldnt run worth a crap after that.

 

[Caretaker109]

Have you tried a warmer plug? Or just the number 8?

 

[Merc man]

Just the number 8 it came with. And baught an extra one too.
But it was a little cooler today too today.
Mabe best to wait till tomorrow and try it. Mabe ill heat the cylider with heat gun first like i did for break in.

 

[Jam Racing 1]

Would shims matter if i stay with same glow plug number as it came with.

The shims under the glow plug button only control the compression ratio on the engine, more shims means less compression, less shims will raise the compression ratio... 3 shims seems to be a good starting point...

I was wondering if it could be the fuel tank. Would it work better if fuel came out from the bottom of tank vs having to be drawn from bottom up.

are you sure you have the lines in the correct places here??? the pressure line goes from the pipe to the cap of the tank to force fuel into the carb via pressure impulses from the exhaust..... the carb feed line goes from the nipple midway down to feed fuel to the carb through the stone filter inside the tank...

You are right that it pushes fuel from midway down the tank thru a stone filter inside the tank instead of feeding from the bottom.... so to combat the half tank lean some guys get is, to tune it at half full and let it run rich on a full tank..... doing it like that seems to eliminate most half tank lean conditions....

 

[Merc man]

Lines are correct. Muffler line to lid. Carb line to tank nipple on right side lower tank.


I also undid fuel lines and blew through impulse line and fuel came out carb line with a good stream.
The oring on lid is also sealing good.

 

[Jam Racing 1]

Ok so reset the idle gap, set both needles to break in and start over again. 3 things needed in the right proportions, fuel, air, and a good glow plug..... if all 3 are right it should run well enuff to finish breakin, also know that LRP need about a full gallon before they are ready to run correctly

 

[Merc man]

What is proper idle gap.
I looked at my tmaxx and tried to put it about the same as a starting point again.

 

[Jam Racing 1]

What is proper idle gap.
I looked at my tmaxx and tried to put it about the same as a starting point again.

Idle gap is about 1mm or so, and that with trims at neutral and idle screw set to not open the throttle any, then when running you set the idle screw to maintain a decent idle not too high or low.....

 

[Merc man]

 

[Merc man]

Hows that look for a starting point for idle gap. It looks about one mil.

 

[NightFlier X4.6]

That looks pretty good to me as well

 

[Merc man]

This motor should run ok on 20 percent?
Was just wondering.

 

[Jam Racing 1]

Idle gap looks ok, as for 20% nitro it will do fine on that, 30% will give it quite a boost at the expense of faster wear....

 

[Merc man]

Had it out today and started it back from factory settings. Fired it up and kept stalling. Richened up the low side got it to adle better let it warm up and had to richen up the high side a lot from factory setting or would just stall when throttled up. It ran good but was running a little hot about 280F. Seemed quite rich as lots of smoke coming from exhaust but i shut it down to cool and will get it back out mabe this week to try again.

Thanks for the help. These little engines can be quite finicky at time.

 

[Merc man]

It was also around half tank when i noticed the temp getting warmer.