Needs help with my nitro engine!

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I've recently done a bb swap on my Revo 3.3. But i found the new engine extremely hard to tune. it can't hit the second gear without running lean and bog down, the engine won't idle, runs very unstable. And the power was way worst than my previous engine all though being a big block with 4 horsepower on the mark...
I have no clue what the problem is rn. Could it be an air leak? Or is it because I'm generally a bad tuner.

I'm welcome for all your suggestions!
 
What engine are we talking about?

I would try setting the HSN, LSN, and idle gap to factory defaults and then use THIS nitro tuning flowchart and see if you can't get better results. An airleak generally will make an engine run lean and be hard to tune so thats a possibility.
 
What engine are we talking about?

I would try setting the HSN, LSN, and idle gap to factory defaults and then use THIS nitro tuning flowchart and see if you can't get better results. An airleak generally will make an engine run lean and be hard to tune so thats a possibility.
SH.28 8 port
I think that it could be the fuel, before i was running 16% nitro 15% oil, and I'm switching to the optimix race fuel which only has 10% oil instead before the engine ran better. And now I've notice that it has been running way too lean all the time, so i assume that it could have something to do with the oil content in the fuel.
Wonder if I can go get some caster oil and add it into the existing fuel making it 20% oil instead?
 
SH.28 8 port
I think that it could be the fuel, before i was running 16% nitro 15% oil, and I'm switching to the optimix race fuel which only has 10% oil instead before the engine ran better. And now I've notice that it has been running way too lean all the time, so i assume that it could have something to do with the oil content in the fuel.
Wonder if I can go get some caster oil and add it into the existing fuel making it 20% oil instead?
The target range for your oil content should be between 8-12% so Id say you're good where you're at. Sounds like it just needs to be retuned for the new fuel if it was running fine before.
 
SH.28 8 port
I think that it could be the fuel, before i was running 16% nitro 15% oil, and I'm switching to the optimix race fuel which only has 10% oil instead before the engine ran better. And now I've notice that it has been running way too lean all the time, so i assume that it could have something to do with the oil content in the fuel.
Wonder if I can go get some caster oil and add it into the existing fuel making it 20% oil instead?

10% is more ideal than 15%, and probably when you ran the 15% you had to lean it out for it to run correctly. I'd stick with the 10%, definitely don't add more oil to make it 20%, that'll run pretty badly.

I have the SH .28-8, and I believe the factory setting is 3 turns out for both needles. Start from there, and you should be fine. Those are pretty easy engines to get running right, and they hold tune pretty well. Make sure the idle gap is somewhere around 1m as well. The SH .28 is a very strong engine and has good top end power as well. If you haven't already, you are going to need to upgrade your driveshafts, if properly tuned that engine will demolish the plastic ones in short order.
 
10% is more ideal than 15%, and probably when you ran the 15% you had to lean it out for it to run correctly. I'd stick with the 10%, definitely don't add more oil to make it 20%, that'll run pretty badly.

I have the SH .28-8, and I believe the factory setting is 3 turns out for both needles. Start from there, and you should be fine. Those are pretty easy engines to get running right, and they hold tune pretty well. Make sure the idle gap is somewhere around 1m as well. The SH .28 is a very strong engine and has good top end power as well. If you haven't already, you are going to need to upgrade your driveshafts, if properly tuned that engine will demolish the plastic ones in short order.
So should i just try and retune it instead? cuz before it was unable to hit second gear even if running lean. Or should i check on the carb before i start retuning?
Btw I'm running in winter, so its pretty cold outside (about -5 to -10 degrees all the time) wonder if i should use some foil on the cooling head?
 
I've recently done a bb swap on my Revo 3.3. But i found the new engine extremely hard to tune. it can't hit the second gear without running lean and bog down, the engine won't idle, runs very unstable. And the power was way worst than my previous engine all though being a big block with 4 horsepower on the mark...
I have no clue what the problem is rn. Could it be an air leak? Or is it because I'm generally a bad tuner.

I'm welcome for all your suggestions!
A couple of things.

1. Is the engine brand new?
2. If the engine is used, has it been gone through to make sure everything works as it should.
 
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