21 Engine Tuning?

[olds97_lss]

I have the Omega 21 sport buggy engine (OMAP202). I have broken it in and I almost have a gallon (trinity mhp 20%) through it.

It seems to be really sputtery (loading up) mid throttle. It will idle all day long and once it opens up after feathering the throttle, it takes off like a bat out of hell. But, if I don't lay into the throttle nice and easy past the 1/2 mark, it seems to load up and sputter pretty bad. If I hold it FWO for about 5-10 seconds, it clears out and takes off. If I go from idle to 1/2 throttle quickly, it flips my maxx onto it's roof. But there's a spot in the 1/2-3/4 throttle that is still weird.

I have fooled with the needles, both high and low and it still does it. If I lean out the top, it seems to do it less, but then the temps creep up and it acts like it's about to flame out. If I lean out the low, it wants to heat up on me but does it just the same.

I try to run my engines between 190 and 230. This has served me well in the past on the past 5 engines I've owned. But, the Omega is a new animal to me and I'm not sure what I'm missing. As it's running right now, the normal temp varies between 190 and 210. And like I said, if I'm easy on the throttle, there's a ton of power in this engine.

It did have the loading up feel to it while I was breaking it in and it seems to be getting progressivly better the more fuel I run through it. So, I'm checking to see if anyone else has run into this scenario, if so, what did you do to help?

I have already taken the engine apart and siliconed the backplate and carb. Did that before I installed it. Also, I changed out the glow plug twice to make sure it wasn't that.

Thanks.

 

[El Pirata]

I've had engines load long after they were broken in. The only suggestions I can offer is clean and flush you fuel system and make sure there are no air leaks that are caused by the heat expanding the fuel system. Make sure you clean your fuel filter as well. Another thought which you've probably already tried is resetting all of the needles to the stock setting and tune from there. Another possibility is that you could also have a blown o-ring on one of your needles

 

[flash183]

don't use silicone on your engine. use only petrol based products.

 

[scottm]

I have had some problems with mid-range rich bog. Supposedly if you put a longer length of tube between the pressure tap in the pipe and the tank, the mid will lean out.

 

[m_podt]

What's the problem with using silicone? You should not use the standard silicone, but there is special 'sensor safe' silicone for high temperatures...

 

[PhillyB]

something copper safe was recommended to me. sold as O2 sensor sealant at advance auto. has an orange color. sealed my motor when i got it, and now a half gallon through with no problems. so far.

 

[newnitrofan]

I use an RTV sensor safe sealant on my motors. You just want to use a thin layer of it not too much at all really and you should be good to go.

 

[flash183]

Originally posted by m_podt
What's the problem with using silicone? You should not use the standard silicone, but there is special 'sensor safe' silicone for high temperatures...

I don't know if you know who Rody Roem is but here is what he says:

"Slicone is a pain for the glowplugs , maybe it can work in the engines as a lubrificant but our general experiences are that once silicone is used in an engine all kind of weird things happen..., for example, the engine just stops and won't restart. Then you change the glowplug it will function for a while and then it stops again...
We are sure some chemical reaction but appear but since we are not total scientists, we prefere not to try all these miracle oils, even if they are after-run, you never know what it will do to your engine."


There's more information on rbproducts.com about the use of silicone. just go to the forum and do a search.

 

[m_podt]

Yeah, but now you're talking about silicone IN an engine. There's nothing wrong using sensor safe silicone as a sealant, so on the OUTSIDE of the engine... The part of the rbproducts page is about lubricants containing silicone.

For example, Rody says on rbproducts.com: "The only place where we use sealant(or silicone) is between the carburetor and the rubber connector of our air-filter, don't use too much sealant." So they do use silicone, but not IN the engine as a lubricant...

By the way, I am using, without any problems, Dow Corning 736 RTV silicone rubber for high temperature applications.

 

[newnitrofan]

Sup guys two places I use the silicone sealant on my engines the ones that make most sense. On the carb base plate and the backplate of the engine. The seal that comes on an HPI or fantom engine will only last so long.

 

[m_podt]

I also had some problems on the carb base. Problem solved using the silicone I mentioned above...

 

[olds97_lss]

It seems ok now. I'll be starting gallon #2 the next time I go out. I just ran a quart through it this afternoon.

Now I just have to fix my damn radio glitch that I can't seem to get rid of.