Fuel issues

[Bryan]

If its too lean, the carb will heat and you'll get vapour lock- where the fuel evaporates in the carb causing fuel to back up, so are you saying with the stock exhaust it ran? And the performance issues may be quite bad, you may have to end up damaging the engine just getting it to run- that's if it will run...

No I had my set up and it primed but I couldn't start it cause I had to go to work. And how do u know the carb it vapour locking? Wouldn't it get hot either way cause it's on the engine? Ahah I probably seem like a huge noob which I kind of am, first nitro engine

 

[ninnon]

No I had my set up and it primed but I couldn't start it cause I had to go to work. And how do u know the carb it vapour locking? Wouldn't it get hot either way cause it's on the engine? Ahah I probably seem like a huge noob which I kind of am, first nitro engine

I'll answer your first question, but you must read the guides I'll link before asking anymore questions. When you lean the engine out, you get less fuel, more air and higher performance (to an extent) but once you go past the Max performance level, your engine overheats (the leaner you get the hotter, as the fuel actually cools the engine, as well as the fins.) Because of this the higher heat causes the carb to heat up more than it should.

Here's the guides:
TUNING: https://www.rcnitrotalk.com/forum/threads/nitro-tuning-tips-and-tuning-flow-chart.60832/
BEGINNERS GUIDE:https://www.rcnitrotalk.com/forum/threads/nitro-rc-beginners-guide.68224/

 

[Bryan]

I'll answer your first question, but you must read the guides I'll link before asking anymore questions. When you lean the engine out, you get less fuel, more air and higher performance (to an extent) but once you go past the Max performance level, your engine overheats (the leaner you get the hotter, as the fuel actually cools the engine, as well as the fins.) Because of this the higher heat causes the carb to heat up more than it should.

Here's the guides:
TUNING: https://www.rcnitrotalk.com/forum/threads/nitro-tuning-tips-and-tuning-flow-chart.60832/
BEGINNERS GUIDE:https://www.rcnitrotalk.com/forum/threads/nitro-rc-beginners-guide.68224/

Ok I'll take a look at it and go from there thanks forte help

 

[ninnon]

No I had my set up and it primed but I couldn't start it cause I had to go to work. And how do u know the carb it vapour locking? Wouldn't it get hot either way cause it's on the engine? Ahah I probably seem like a huge noob which I kind of am, first nitro engine

Ok I'll take a look at it and go from there thanks forte help

sounds good

 

[Bryan]

Ok I'll take a look at it and go from there thanks forte help

One last thing is the fuel being lean wouldn't have anything to do with the exhaust system right?

 

[ninnon]

One last thing is the fuel being lean wouldn't have anything to do with the exhaust system right?

you lean the engine from the adjustment screws on the carb.

 

[Bryan]

you lean the engine from the adjustment screws on the carb.

Yeah that's what I'm saying so exhaust had nothing to do with leaning fuel just performance and delivery is in the exhaust

 

[griff7373]

Your exhaust has alot to do with it, if you don't have enough back pressure the fuel will not get to the carb as it should.

 

[Bryan]

Your exhaust has alot to do with it, if you don't have enough back pressure the fuel will not get to the carb as it should.

I should have enough back pressure tho right? Like the header is twice as long but the back pressure should still be there no?

you lean the engine from the adjustment screws on the carb.

Like I had a stock are up for the exhaust and had the engine in a bench stand and the same exact results was occurring, so like I just feel like my longer header isn't the issue, if it really is that's gonna suck cause it's perfect for the application I'm doing, and rc snowmobile

 

[ninnon]

I should have enough back pressure tho right? Like the header is twice as long but the back pressure should still be there no?


Like I had a stock are up for the exhaust and had the engine in a bench stand and the same exact results was occurring, so like I just feel like my longer header isn't the issue, if it really is that's gonna suck cause it's perfect for the application I'm doing, and rc snowmobile

The exhaust effects everything really- because of the way a two stroke engine works, both the exhaust and inlet ports are open at the same time, meaning that as fresh air fuel mix goes in, some leaks out. This is where the exhaust comes in. The exhaust gases flow down the exhaust through a series of chambers tuned dependent on the application of the pipe, they then reach the end and deflect off of a cone, this sends back a pulse of exhaust gases forcing the leaked fresh fuel mix back into the cylinder. You putting a kink in the header is probably destroying or disturbing the pulse, along with other things- causing the engine to burn more fuel and run richer, so something else is probably causing your engine not to run. Your exhaust design may also be disturbing the pressures needed to force fuel into the engine, thus causing the fuel not enter the engine. If I could see a video that would be great

 

[Bryan]

The exhaust effects everything really- because of the way a two stroke engine works, both the exhaust and inlet ports are open at the same time, meaning that as fresh air fuel mix goes in, some leaks out. This is where the exhaust comes in. The exhaust gases flow down the exhaust through a series of chambers tuned dependent on the application of the pipe, they then reach the end and deflect off of a cone, this sends back a pulse of exhaust gases forcing the leaked fresh fuel mix back into the cylinder. You putting a kink in the header is probably destroying or disturbing the pulse, along with other things- causing the engine to burn more fuel and run richer, so something else is probably causing your engine not to run. Your exhaust design may also be disturbing the pressures needed to force fuel into the engine, thus causing the fuel not enter the engine. If I could see a video that would be great

Yeah for sure I'll send one now! Here's the link

 

[ninnon]

Yeah for sure I'll send one now! Here's the link

That exhaust really is a bit mental...Try putting the stock one on, were you going full throttle too? That's also running too lean and the idles too high. Once you've put the stock exhaust back on follow the tuning flowchart. As for the exhaust, why can't you put a rear mounted one on like this:

Just PLEASE, PLEASE, PLEASE don't buy a dual stinger exhaust...

 

[Bryan]

That exhaust really is a bit mental...Try putting the stock one on, were you going full throttle too? That's also running too lean and the idles too high. Once you've put the stock exhaust back on follow the tuning flowchart. As for the exhaust, why can't you put a rear mounted one on like this:

Just PLEASE, PLEASE, PLEASE don't buy a dual stinger exhaust...

Na man it was randomly revi get up on its own, and well I could mount it back but if u know snowmobile the exhaust is in the engine compartment and that was what I was trying to go for

 

[ninnon]

Na man it was randomly revi get up on its own, and well I could mount it back but if u know snowmobile the exhaust is in the engine compartment and that was what I was trying to go for

Yeah....If you weren't doing anything then you've got an air leak somewhere, probably the exhaust. On this guys Snowmobile he had the stock exhaust mounted on the side. Do you still have the stock exhaust? I know it'd be a shame to not use the old one but it's just not a good idea to use an exhaust like that and expect it to work properly, it's just the way things are sometimes :

Sometimes with nitro you can't have perfect realism. All onroad cars that haven't been "upgraded" with a rear exhaust have the exhaust on the side. If you really needed realism then it'd be best just to get a fake exhaust and stick it where it goes.

 

[Bryan]

Yeah....If you weren't doing anything then you've got an air leak somewhere, probably the exhaust. On this guys Snowmobile he had the stock exhaust mounted on the side. Do you still have the stock exhaust? I know it'd be a shame to not use the old one but it's just not a good idea to use an exhaust like that and expect it to work properly, it's just the way things are sometimes :

Sometimes with nitro you can't have perfect realism. All onroad cars that haven't been "upgraded" with a rear exhaust have the exhaust on the side. If you really needed realism then it'd be best just to get a fake exhaust and stick it where it goes.

Nope I bought the engine than if u guys heard of extreme rc mods I got a pipe from them for my .28 like I wanted to build a ex sled so I went out got my self a nice motor for cheap and started my build, but I guess I'll have to get a header that will direct the pipe under the seat, like where the seat would be on a real sled

 

[ninnon]

Nope I bought the engine than if u guys heard of extreme rc mods I got a pipe from them for my .28 like I wanted to build a ex sled so I went out got my self a nice motor for cheap and started my build, but I guess I'll have to get a header that will direct the pipe under the seat, like where the seat would be on a real sled

Oh....Oh My. I never noticed that that was an ERCM pipe. The sacrilege!
But seriously, they are some of the best pipes out there, you have a great pipe there- I'd fit on a normal header and just stick with a side exhaust, your problems will go away (mostly) I'd certainly recommend that, it'd be a waste of a good pipe- it may not be what you want but You really would regret choosing looks over performance. Sorry to burst your bubble but That's what I'd be doing....

BTW, ERCM are one of our sponsors.

 

[Bryan]

Oh....Oh My. I never noticed that that was an ERCM pipe. The sacrilege!
But seriously, they are some of the best pipes out there, you have a great pipe there- I'd fit on a normal header and just stick with a side exhaust, your problems will go away (mostly) I'd certainly recommend that, it'd be a waste of a good pipe- it may not be what you want but You really would regret choosing looks over performance. Sorry to burst your bubble but That's what I'd be doing....

BTW, ERCM are one of our sponsors.

Ur sponsored? That's sick , and yeah I'll have to cook something up here thanks to all for the help I'll post back when I have a different set up

 

[Rolex]

Ninnon has a lot of good info for you. Your ERCM pipe is about the best you can get, but your 'bended and extended' header and stinger will offset all the improvements you would get with it.

 

[Bryan]

Ninnon has a lot of good info for you. Your ERCM pipe is about the best you can get, but your 'bended and extended' header and stinger will offset all the improvements you would get with it.

Yeah I'm gonna scrap the one I built I guess and make a new header that will be the same length as the of a savage one I have on now, or the sliver part of my whole header system and run it so the pipe runs out the back

 

[Rolex]

There comes a point with these engines when LOOKING cool and RUNNING great is a long ways apart.
As ninnon mentioned, there's a fortune in time, money and research that goes into developing any improvements in a nitro engine, so there's very little you can do that will change it for the better.
Prime example....
A supercharger LOOKS SO COOL but you'll NEVER get one iota of improvement with it, even if you can make it run.