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o.s. .15 running hot please help

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ramos617

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ok i mas messing with the screws on my os and it strted running good but very hot i dont know which one is to lean or rich PLEASE HELP




SCREW BY GAS LINE
http://i245.photobucket.com/albums/gg74/nukkah617/Image001.jpg

SCREW BY CARB/THROTTLE
http://i245.photobucket.com/albums/gg74/nukkah617/Image000.jpg


http://i245.photobucket.com/albums/gg74/nukkah617/Image002.jpg
 
What is "very hot"? We can't tell you much of anything by looking at the needles. Other than which does what.

Also, can't see your photo's. They are only text links.

Regardless, like I said, we can't tell much by seeing them anyway.

Firstly, I'd not hesitate to say that the OS15 isn't powerful enough to get very good performance in a t-maxx. Don't get me wrong, it's a very good engine, but just not enough power to lug the maxx around with any authority. I ran an OS15CV-R(X) in my maxx many years ago. It would run "well" at 280-290F on average in that truck with 18/72 gearing. Never did I get a wheelie or really good pop off the line. I had good smoke and good clean engine running, but temps were overly high due to the engine working so hard in such a heavy rig.

I had the same model engine in a Losi XXX-NT (light 1/10 2wd stadium truck) and it ran consistently and cleanly at 215F all day long in 80F degree weather. That's what tells me the engine isn't enough for the t-maxx.

When I had mine though, the OS 18 CV-R didn't exist yet. When that came out, the OS15CV-R went away (or at least tower discontinued it). The 18 would move the truck better and more than likely run cooler as a result. For $100, I'd save up and get that if I were you.
 
would a 3.3 just bolt on without modification

olds97_lss said:
What is "very hot"? We can't tell you much of anything by looking at the needles. Other than which does what.

Also, can't see your photo's. They are only text links.

Regardless, like I said, we can't tell much by seeing them anyway.

Firstly, I'd not hesitate to say that the OS15 isn't powerful enough to get very good performance in a t-maxx. Don't get me wrong, it's a very good engine, but just not enough power to lug the maxx around with any authority. I ran an OS15CV-R(X) in my maxx many years ago. It would run "well" at 280-290F on average in that truck with 18/72 gearing. Never did I get a wheelie or really good pop off the line. I had good smoke and good clean engine running, but temps were overly high due to the engine working so hard in such a heavy rig.

I had the same model engine in a Losi XXX-NT (light 1/10 2wd stadium truck) and it ran consistently and cleanly at 215F all day long in 80F degree weather. That's what tells me the engine isn't enough for the t-maxx.

When I had mine though, the OS 18 CV-R didn't exist yet. When that came out, the OS15CV-R went away (or at least tower discontinued it). The 18 would move the truck better and more than likely run cooler as a result. For $100, I'd save up and get that if I were you.
Click to expand...
you can copy and paste pics
 
ramos617 said:
would a 3.3 just bolt on without modification
Click to expand...
No. The 3.3 requires different throttle linkage and a new exhaust setup. The OS15 you have is a rotary carb/side exhaust engine. The TRX3.3 is a slide carb/rear exhaust engine (requires traxxas specific header).

The 18CV-R would more than likely be a bolt in if you can figure out what crankshaft you have. Whether it is short or standard threaded. It to can be bought as a rotary carb, but is also a side exhaust engine.

OS 15 CV-X rotary carb standard shaft
osmg2034.webp


OS 18 CV-R(X) rotary carb standard shaft
osmg2104.webp



ramos617 said:
you can copy and paste pics
Click to expand...
I know. I did and realized what you were showing which were just shots of the HSN and LSN.
 
I'm not sure what model its a 15 or 2.5 bcuz it has the black trans how would i figure out which one it is



also would a 25 engine fit bolt on
 
25 as in big block? It wouldn't. Traxxas 2.5cc (which converts to .15ci) would require the same parts as the 3.3cc (converts to .20ci) to run it. They are basically the same engine as far as installation is concerned. Slide carb/rear exhaust.

It's tough to tell since all the 15 and 2.5 parts are interchangeable. The obvious stuff could be either truck with the other trucks parts, so you wouldn't know really.

The original 15 maxx came with a side exhaust, rotary carb engine, like what you have now.

Got a whole photo of the rig?
 
 
I wouldn't bother with the 2.5/2.5R, I would go straight to the 3.3.
Either engine will require a new header, exhaust pipe, throttle linkage, throttle pivot post. I think that's it.
Links:
Throttle pivot post and pieces
throttle linkage
pipe
header

May possibly need:
flywheel nut
pipe hanger

So, roughly $70 worth of stuff. However, you may be able to find the pipe/header on ebay cheaper.
 
Last edited:
if u want a reliable motor that shouldn't require any mods in your truck, i would get a os 18cv-r.
 

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