SyCo_VeNoM

I have 2 HPI Nitro star .15FE's I'm trying to use I got them both with old HPI MTs I bought.

the 1st one runs fine when throttle is low but once I open the throttle past 75% it it dies out.

The 2nd will turn over but will die out almost immediately after I remove the glow plug igniter and is very hard to restart. I also have to have the throttle open over 30% of the way to get it to start. I've JUST got this engine and have not had much time for it due to rain on almost every day I could work on it.

Both are using brand new MC-9 glow plugs. Both glow plugs start up my HPI Nitro Star .15 in under 1 second (rotostart).

So does anyone know what kind of issues these 2 could have?

quietnas1

First thing. How old are the engines?

SyCo_VeNoM

They are out of original Nitro MT's so I'm guessing 6+ years old. I'm a tad strapped for cash or I would say screw it and buy 2 brand new ones.

GlassBullet

My Feedback: (1)

How much have they been used? and Did you buy the cars for the engines? cause it sounds like the one you have is working fine

SyCo_VeNoM

I have a total of 3 engines and now 3 vehicles. and sadly only 1 engine that works with 0 issues, mainly due to the engine being brand new.

The one that dies at 75% throttle I got with my 1st Nitro MT that I got used. I personally ran 3 tanks through it before pull starter spring snapped. This engine was pretty clean and the car looked well maintained

The one that dies once the glow plug ignitor is removed was obtained when I bought a box of MT1 parts dirt cheap off a guy that was getting out of the hobby, luckily once I went through the box I had the whole truck including all the electronics and screws, I was actually expecting 30% of the trucks parts to be missing. This engine I know was not well maintained due to how it was mounted to the chassy. The guy had lost the carb screws and zip tied the carb to the chassy to stop it from falling off and had 2 screws that were too small jammed in to carb from moving left and right. I've since replaced the screws with two that properly hold the carb on and have no play. I also had to replace the clutch shoes due to him having a clutch on it that never disengaged, the box had 3 melted spur gears in it which is why I'm guessing he gave up on this truck. I personally have this engine run a total of 15-20 seconds. The carb on this engine looks older than the other .15FE that I'm having issues with. Also the engine was so dirty it wasn't funny, I actually had to chisel off the dirt seeing a soap degreaser wouldn't even budge it.


Thats about all I know about the history of the engines that have issues.

GlassBullet

My Feedback: (1)

For the 75% one, how does it cut out? Does it bog down or what?
and for the other, try a new glow plug

Barber420

My Feedback: (1)

What brand of fuel are you using? Do you have stock needle setting specs to start from? Have you tried any other kinds of glow plugs? O.S. #8's and A3's always work well for me. I'm guessing the engine that appears to have been abused is probably junk. A nitro engine in the wrong hands can last as short as break in and be junk. If you're tight with cash you could see what a piston and sleeve for the engine costs, but I find it's usually more economical to buy a whole new engine in most cases.

SyCo_VeNoM

well the 75% one sounds fine, its speed increases rapidly and it doesn't seem to lack power till it hits approx 75% throttle than it just cuts out completely while in the middle of reving. It can be restarted fairly easily after it stops.


the other I've tried 3 glow plugs in. 1 was the one I use in my new engine and the other 2 were brand new out of the box, all worked fine in my other engine. So I'm fairly certain its not a bad glow plug issue. Since I 1st asked about it I've been reading other sites with info on nitro engines and think it might be compression seeing the flywheel has almost no resistance when turned by hand. So tomorrow I'm planning to check if it has air leaks.

Barber420

My Feedback: (1)

Yeah, I figured you'd already checked for air leaks when inspecting them. Do that. Actually, you might as well had just tear the engines down, clean them up, inspect them, and reseal them upon reassembly. Sorry to say, I have a feeling they're probably junk, or real close to it. Hopefully you can get at least one of them running good though.

SyCo_VeNoM

Traxxas 20% nitro fuel.
I had to set it to stock settings, the guy that I got it from had the idle screw set to no opening and was using the trim on the remote to set it so the engine would die on braking. Which is probably why the truck itself wasn't very scratched up.

Actually tomorrow will also be the 1st time I fire the engine up in over a month. The vehicle I ended up putting it in I just finished today and have not had the chance to run. The behavior I said was from when it was in my 1st MT. So tomorrow I'm planning on trying it out. While I'm at it I'll try different glow plugs seeing I now have 1 from HPI and some with a different rating. I'm actually hoping it turns out to be just a glow plug issue.


Actually I wouldn't bother replacing the piston and sleeve on the abused one. I know for a fact I could buy brand a new engine for $10 over their cost

djzachtyler

My Feedback: (4)

generally ya it is more justifyable to buy a new engine... the piston and sleeve sets generally run in the ball park of half the cost of the engine, while the other costly part is usually the carb and crankshaft...

I would just save up a hundred or so bucks and get yourself an OS engine they are pretty low cost for the .15 & .18 CV series, and are pretty reliable

djzachtyler

My Feedback: (4)

I also forgot to ask are they the older nitrostar .15s with the flat cooling head? If so you definately want to junk them as soon as you can afford to. the Nitrostar .15 is a pretty crappily built engine IMO. I would definately just replace it when money alows....

Barber420

My Feedback: (1)

I agree. The O.S. CV engines are reliable, cheap, and tough. I run an O.S. .15 CV-x in my RC10GT and I love it. It lacks a little in power, but if you step up to the .18 CV that'll solve that problem. I wanted the .15 because I race on a REALLY tight and technical track, so I needed the bottom end and mid range power over top speed.

SyCo_VeNoM

Actually the 1st one I had issues with ran perfectly fine today once I put a different rated glow plug than what I was originally sold for it. I actually found a hobby shop with WAY more knowledgeable people working in it than the one I was first going to.

and yes the 2 that had issues are the flat tops and I already started looking for a replacement for the one that won't stay on at all. I found the air leak on it. There is a very large leak in between the crankshaft and bearings it was losing air faster than I could blow into the engine, which to my knowledge is unsealable. So I'm gonna gut it for the few useful parts for my other engine that is working which is the same model and junk the rest.

I forgot to add
Thanks everyone for the help