First Nitro Engine - No top end power?? Help!!

[Valiante]

Having only ever owned electric motors before, this is all very new to me..

I'm a couple of months into owning a Conquistador and have started taking it off-road, however I've noticed that the greater the load, if I max out the throttle I get the opposite result and the revs drop or even die out altogether.

My father-in-law bought exactly the same model at the same time and he can quite contently bounce around the field at full-throttle with no bother, reach far higher RPM's than I.

If however I start her up and let it free-wheel in the air, I can rev well beyond what I can achieve whilst moving.

Any ideas?? onder2:

 

[vbgagnon]

It sounds like your hsn is too lean. To you have any way to measure the temps? IMO richen your hsn a bit and you will notice better power. Remeber you want to have smoke all the way through your power band.

 

[Monkey Wrench]

I'd have to agree with VB, but without knowing what kind of engine you have, what type of fuel you've been running and the like, it's hard to really nail down any sort of possible causes and potential fixes.

Best thing to do, set your needles back to their factory settings and go from there, but it does sound like you HSN is a bit on the lean side.

Are you getting consistent smoke as you throttle up?

 

[Valiante]

Forgive my ignorance, guys.. I'm really new to this game.

I'm guessing my "hsn" is the high-speed-needle (or top-end screw)?

I've tried playing around with this, but I don't really know what I'm doing to be honest. The car itself is a Conquistador, with a Team Infinity 18S engine. The fuel I'm running is Model Technics blended fuel, created and supplied by a local model company.

Until I get the chance to fiddle around with it, I won't really be able to answer any questions about smoke across the rev-range, etc.

Also, I've read about a bottom-end screw (or low-speed-needle) but I'll be darned if I can find it!
Your help is most appreciated!!

 

[AC48]

Yes, the HSN is your high speed needle, it adjusts the fuel/air mixture at higher RPMs. Unscrewing it will give you more fuel, and screwing it in gives you less (leaner). To me it sounds like your engine is starvving for fuel when you give it full throttle, so I would say to richen it (unscrew it) at 1/8 of a turn incriments and see if that helps.

Your LSN is on the slide valve if your engine is a slide carb, or on the rotary part if your carb is a rotary carb. It does the same thing as the HSN, just for lower RPMs.

If your really having trouble try to find out the factory settings for your engine, and tune from there.

 

[Valiante]

Cheers AC, I will try that next time I'm out. She ticks over sweet as a nut and runs at half-throttle really solid, so hopefully (as you say) just adjusting something that only affects the higher RPMs will help.

At least now I know what to do with that screw, before I was just guessing!

Thanks again - I'll post back in a few days and let y'all know how I got on.
Peace out.

 

[olds97_lss]

I agree with the others. Richen your high speed needle a quarter turn, drive it a little bit from slow to wide open a few times to see if it changes.

To richen, you want to turn the needle ccw (counter clock wise).

 

[Valiante]

Is anyone familiar with ACME Team Infinity engines? I've had a good look and I can only see one screw, presumably the top-end.

Is it possible the bottom-end mixture could be fixed? Or that both top and bottom are somehow combined into this one screw?

onder2:

 

[Candyman]

I'm not familiar with that brand specifically. But looking at pics on the link you provided above, it does look like there is just one needle. Thus it's called a single-needle carb. The low speed mix is fixed. Carbs like this are nice for beginners because it limits the amount of adjustments you can make. Although it doesn't bring the full potential out of the engine, it does keep you from horribly mucking up the tune.
Look in your manual to see if they tell you where your HSN should be set to start with. It should say something along the lines of "your needle should be set x turns from bottom" or something like that. That's what's known as "factory setting". Usually that's where you'll start tuning.

**OK, just found an online manual for the 18S engine, but it doesn't say what factory settings are. So I'd richen the needle a bit and go from there, just like everyone else said.***

 

[Valiante]

just found an online manual for the 18S engine

Ahh, I've lost my manual.. could you link me? -xmas-

 

[olds97_lss]

Here's a link for the 18S

It says 2.5-3 turns out on the main needle for a starting point.

Kind of funny how it tells you to turn the propeller over a few times after putting a few drops of ARO down the carb... isn't this a land vehicle?

 

[Valiante]

Hehe - it is a land vehicle, yeah. I think originally the 15s was used in the cars and the 18s in planes. I remember the manual saying funning things like that!

 

[Valiante]

Well now I feel slightly sheepish!!

It turns out it was O'Donnell "Performance" Glow Plug that was causing the problem. I switched back to the original plug (which I hadn't used since day one) and it now runs like a dream and revs beautifully.

But thanks to your help I was able to put the mixture back to the factory setting after having played around with it. Question is, what do I do about this plug that's supposed to improve performance, not hinder it?! I guess it was only £5.... Me = :loser:

 

[MEGA MAXX]

hi

hmm arent ACME a cheap korean make?
that may be why the manual is stating a prop.

just watch you dont break it, parts are hard to get.

how much did you buy it for?

 

[Valiante]

Umm, I paid about £150 for the car from my local model shop, then another £30 for the "nitro startup set" which basically consisted of fuel, a glow-plug starter, various tools, and a fuel filler bottle thingy.

Parts seem to be relatively easy to come by thus far.. my father-in-law has broken his (bought at the same time) more than once (!) and has had no trouble sourcing replacement parts from both our local shop, and from Nitrotek.. which is also where I've bought a few upgrades.. aluminium parts, etc.

 

[Mondo]

Acme

I know the car you're referring to. I don't own one, but I've seen them
Finally I realsied you're in the UK, no offence but completing the Location Field in the Forum helps a lot too.

I would also look at an alternative fuel. Model Technics fuel is called "air filter cleaner you can run your buggy/truck on" at my local track. No one has a good word to say about it.
My first experience with this fuel was about 4 years ago with my T-MAXX. The car wouldn't idle, hold a tune or show any consistency at all. I blamed the TRX2.5 engine (as we all do) but the problem was the Model Technics fuel. I changed fuel and the MAXX ran well. I've never used Model Technics since and I suggest you try Byrons, ODonnel or Blue Thunder Sport forumula, all at 20-25% Nitro

I've said this before: Here in England you may know how to brew beer, but when it comes to Nitro fuel, leave that to the Americans.

 

[Valiante]

Humblest apologies.. I have now filled the holes in my profile, something I've been meaning to do but didn't quite get around to.

And thanks for the fuel advice, once I've run out this bottle I'll see if I can source some of the brands you mentioned.