CustomTamiyas4Life

My Feedback: (34)

I just replaced the piston and sleeve and heat cycled it with 6 2-3 minute runs and 3 4 minute runs and all the other stuff like bdc and full cooling. The run after break in I had it tuned great and it was running superb until it just started to run like crap almost like it was bogging. THe next day I go to run it with a new glowplug and it runs good for about 30 seconds to a minute then starts the weird bogging again. The weird thing is is that it will fire right back up after it stalls or is shutoff, unlike with a bad piston and sleeve or overheating. I tried tons of different tuning of the low and high end needle but it didnt help much. I also tried 2 different fuels to make sure it was not bad fuel.

Here's some videos. Be sure to turn up the volume on the first one. I also have a video showing how easily it starts back up after the stalling.

http://video.google.com/videoplay?do...01610072&hl=en
http://video.google.com/videoplay?do...13748506&hl=en

ThermalRD

Looks to me like its bogging when you hit the throttle, and starts fine. You sure that tune is right? Seems your HSN could just be really lean.

CustomTamiyas4Life

My Feedback: (34)

Well in the vid it's at factory setting which is pretty darn rich.

Bria1

Dang, that sounds just like what my TNX is doing. I've tried retuning it with no luck. I just got my repair for that in the mail today.

CustomTamiyas4Life

My Feedback: (34)

Awwww you've gotta be kidding me. Just what I need is another 150 bucks to spend on the friggin rc's. This is the first time I've ever been unhappy with tamiya....and I never turned in the warranty...arrrrg.

Bria1

I didn't try a piston and sleeve in mine, but I cleaned the carb, resealed it, tried a new tank and fuel lines, reset the needles to factory settings, tried richer and leaner on both needles, tried different glow plugs and it still sounded exactly like yours does in the video. Mine restarts fine and is running around 240 degrees when checked with a raytek gun. I was too fed up with it to try the piston and sleeve, so I just got a new engine. It's $110 for the new engine at tower compared to $57 for a p/s. It was worth the piece of mind to me.

CustomTamiyas4Life

My Feedback: (34)

Not too badly priced but still too much seeing I just spent 130. I'm gonna try to clean the carb and fuel lines tomorrow probably and see how it works then. I'm just fed up at the fact It ran awesome for about 15mins then randomly started running bad and the piston and sleeve ar brand new.

Dil

sounds like its dying for fuel, at idle, have you tried tuning the low speed needle,??

your high speed neddle should be ok from what i saw, theres plenty of smoke so that should be fine,

CustomTamiyas4Life

My Feedback: (34)

Ya I put it back to factory and tried richening both needles some. When I give it gas there's alot of smoke from the exhaust too.

mordraid

My TNX did that too. Check out the high speed needle CUP. Mine was loose and enven if i was richening the needle, the cup would unscrew too. Tighten it and see.

Looks to me also like you low speed needle is a bit on the lean side. Reset it flush with the carb.

mike54937

Thats crazy! Thats the same excact thing my Warhead is doing! Can't figure it out. I took it to my LHS
and they took the motor out and removed the carb. found a chunk of O ring in there thought it was the prob. We fired it up in the parking lot and it ran great. Took it out and ran it today, same damn thing. I hope its not the motor, don't have the cash right now!

CustomTamiyas4Life

My Feedback: (34)

Ya I'm really hoping it's not the engine. Mordraid I'll check that out.

CustomTamiyas4Life

My Feedback: (34)

Ok now I am getting beyond aggrivated and want to kick the thing. Rebuilt the carb last night, made sure the glow plug was good, richened it to the moon and the piston and sleeve are new. It doesnt seem to be tuning well as I was richening it 1/2 to full turns and there was no large difference in revs or performace. I dont know what to do now the powerplant is brand new pretty much and tuning isnt helping.

jombo

are you tuning the lsn too, or just the hsn?

CustomTamiyas4Life

My Feedback: (34)

Tried several combos with both.

jombo

this is what i do when all else fails. i start the truck then after its warmed up i pinch the fuel line. if it stalls before 5 and 7- 1000 then its too lean after fixing that i adj the idle a little. then i do some long high speed runs if it stalls as it going fast the hsn is too lean, just keep doing it till it dosent stall anymore and re adj the idle. i have solved the most stubborn engines this way and so far its worked. this is not an easy fix it usually takes me 1 to2 hours to do it this way but it does work.

CustomTamiyas4Life

My Feedback: (34)

I may try it but as I mentioned earlier I dont see why it used to be so reliable but now gone to crap.

jombo

it may be lean, but not enough to burn the plug up but enough to make it run horrible.

Bria1

Did you check the bearings in the engine when you rebuilt it?

CustomTamiyas4Life

My Feedback: (34)

No way is it too lean. I backed out both needles in and out about a turn from factory settings and it still did the same thing. Not sure if I checked the bearings....I know I did the clutch bearing and oil the bushing on the connecting road and stuff. Will have to take the engine off I guess.

randy12

that sucks are u going to take the piston and sleeve out again? it also might be the timming is off too but not that sure of what it is sounds like you basicly did almost everything i hope you get it to run again so we can have a drag race soon later

Bria1

Timing off on a RC nitro engine???????????[&:]

Tbizz

hmmm....

Did you happen to crash the truck at all causing a crack in the gas tank?

Remove the fuel line from the carb...If you blow in the exhaust line does the fuel come out?

I find it hard to believe theres a major problem with that engine.

CustomTamiyas4Life

My Feedback: (34)

Havent crashed it much yet but what I do know is that if I blow in the exhaust line I can prime the engine so I dont think that's the problem.

mordraid

yep TBIZZ is right, you may have an air leak in your fuel line. Check you fuel line and replace them (it's cheap)

Did you still got the stovk TNX fuel tank ? If so it really need to go. The primer on the tank is a sweet spot to have an air leak. An air leak will act somehow like its too lean and is maybe your problem. You can get an ofna tank for about 10$ almost in every good hobby shop.