How do you know when you've lost the compression so much that the engine won't run? My LST2 won't stay running for very long... I had it running today... ran it for about 10-15 seconds, and it died.. and never started again. I pulled the head and peeked in... it looks like the piston is pretty loose in the sleeve... and when it goes up and down, I notice a layer of fuel/oil on the sleeve.... I would think that this layer would be wiped from the piston... am I wrong? I can also see a visible line where the piston stops in the sleeve. None of my other engines has that... think I may need a new p/s? It only has 1/4 - 1/2 gallon through it... was broken in per LOSI instructions... anyone know if it's still under warranty?

Here is a pic of the sleeve... unfortunately, it doesn't show much... but it does seem to have less compression than my TM323...

here is something i tried .... with the head on take the engine off the truck turn the flywheel till you get resistance, holding it by the flywheel tilt the engine to the side with compression and see if the compression will hold it up or will it fall over if it holds up then more than likely its not shot if it falls then it may be gone but on a 1/4 to 1/2 gallon it should be fine unless it was ran extremely lean ....300+ degrees,................mine did the same thing but after about 7.5-8 gallons of fuel

I just can't think of anything else.. I've switched glowplugs... to one that I KNOW is good (not brand new... but fairly new) and it wants to fire... but just spits and sputters... like it's trying to fire... but just doesn't have enough compression. I'll get a brand new glowplug and see if that's the issue... it's got compression.. just not much... not near as much as my 3 gallon TM323... or my 2.5 gallon 2.5r with score marks in the cylinders... LOL

take the piston and sleeve out, see hwo far into the sleeve the piston will go before it stops form the pinch, there should be about 1/8th of an inch gap, if you have 1/8th gap then the pinch if okay, next step is, is the head button stripped? if no try replacing the shims, still no go see if you can get it warranted, should conk out the quickly.

I Can't See a New Engine Just Dieing like That.......... Are you Sure it's Getting Fuel? The Fuel Filter or one of the Carb Needles Could be Blocked?
(I'd also Try a New Plug with a Fresh Charge on the Ignitor and Roto Starter.....)

I agree with Sublime.

Well, I feel the same way... there is NO reason it should die that quickly. Even my 2.5r has lasted over 2.5 gallons. I went to my LHS and picked up new glowplugs and fuel line (mine is pretty baked) to see if it would help. I'm sure I'm getting fuel... it acted like it wanted to fire... but it just wouldn't... I adjusted the needles a little... thinking it may be too lean... or fat... nothing.. and when I'd plug the end to prime more fuel through it... it stopped acting like it wanted to fire... (guessing I flooded it a little... 'cause it would start acting like it wanted to fire after throttling up a little... that's why I thought it may be lost compression... I'm going to change the plug with a NIB... and charge the batts and see how it does tonight. I wanna get both trucks running for Saturday.. it's my daughter's B-day... (and mine is 2 days later) and I want to take her out R/Cing.

So, I changed out all the fuel line... and installed a new MC-9 glowplug... but didn't have a chance to try to start it... and my daughter's b-day party is tonight, so I might not even get to start it until tomorrow. [:@]

I dont know if this is it,but when my 3.3 in my tmaxx acted like it wanted to fire but just couldn't i checked the OWB and it was froze up i cleaned and oiled it and it started up on first pull.

That is a possibility... but the other night, I pulled the engine.. took off the rotostart and checked the OWB... it SEEMED to be working correctly.... (I turned it one way... it grabbed and turned the crankshaft... turned it the other way... it was loose). Right before I couldn't start it at all... it ran for about 20 seconds... then just died. I tuned it a few weeks ago... so it couldn't be THAT far out of tune...

hmm change all ur fuel lines mabey an air leak?or bad fuel?

I would doubt it's bad fuel... it's only a few months old... kept properly... and AFAIK... the Revo runs fine... right now, I'm just waiting to have a chance to test it out... I'm probably going straight to the park from work today... so I won't be able to run the LST2 today... but maybe tomorrow.

my glow starter has a gauge on it to tell me my glow plug is bad. The engine runs so rich for the first few tanks that it could be a glow plug that's the first thing I check. The top of the piston will tell you if you over heated it and look on the skirt of the pistons from the exhust port that will let you know if the piston is loose. I have about 3 gallons on mine and runs great and replaced the glow plug 4 or 5 times.

Alright... starting to get a little frustrated here... changed the plug... changed the fuel line... still no dice... got it to fire, but it dies shortly after... I went to a colder plug... so I'm going to try a hotter plug (MC-59) and see if that's it.... also changed the header gasket since the other one was torn... if this doesn't work... I"m going to call Horizon.

Edit: I know it's not the fuel 'cause I started the Revo with the same fuel (pulled it out of the tank and put it into the Revo) and it ran GREAT.

What's factory settings? I can't remember... I'm going to try going back to factory settings... see if that works.... other than that, I can get it to run... but it intermittently dies... and won't start back up. It's got all the signs of a toasted engine...

Ok, I found the factory settings. I've also e-mailed Horizon's customer support. [:@] <--- that's how I feel right now.