If the track is open on Sunday I'll likely go burn as much fuel as I can. If you're there, we can play around with it and figure some stuff out. And I have almost always had a Nova/Nova based engine somewhere in my pitbag or car. =)

If it isn't raining and it's above 5 deg.. I'll be there for an hour so...

A little help guys....

I tried searching but I'm not sure what to search for and haven't had any luck finding my answer yet. I have been having problems getting my 21-4 btt to idle consisently and I was just working with it and got it doing well. The problem now is that when I go WOT and let off the throttle quickly it will just die. Is that too rich or lean? LSN or HSN?

It has m2c clutch with .95 springs, 9901/41021, c6tg and Odonnel speed 30%

Thanks...

I had the same problem with my bonito and it ended up being the clutch bell bearings where bad. That may not be your case but its something to check.

How large is the idle gap?
If the plugs okay, maybe it's indicative of a overly rich LSN setting/ possibly lean on high end. I've had similar issues with the P5..just throwing it out there..

my first thought is the idle gap is too small, but I would check the clutch second. the springs may be a bit soft and they are staying engaged when you slam on the brakes...

third, you may go back to flush on the top and bottom, and then reset the idle. then retune the bottom end to not load up, then slowly lean the top, but not to far from flush....

try richning the hsn 3 hrs and lean the low speed maybee you are too rich on lsn side

I have "problems" with my idle also. It always two stage. I belive the +4 engines is this way and infact, it is not a problem.

Always when i get a steady idle from them, i do not get the performance i like and belive theese engies should have. So, i let the engines twostage a bit, never flames out, always good throttle respons and a good running engine :-)

its funny previous to me trying the novas ive had os engines i thougfht this time around ill go nova im so happy so far now i work out the tuning of them a few thing i have learned is

if you get a awesome idle with them the tune is crap on track
and if you get them sweet on the track the idle seems weired

ive actully set mine up realy well now there is a few weired things to get them to fly but i have some awesome punch from out of the corners now and great top end as well ad good milage as for power i keep up with or in front on our big straight with ninjas and os motors but the speeds kill me still but not by much

i run a couple a btta engines

All right guys, help a brother out. I bought a brand new Plus-4btts about a month ago and have slowly breaking it in. I used the heat method and broke it in just like the "break-in" bible says, then been running conservatively on the track in practice. The motor was so tight new it took me 1 hour to get it started. As soon as it would go up in the sleeve it would freeze, used comp heat to heat it up to 220 every time. Finally it turned over and got it started and idled the first tank through...... That is just a little history.

Now the motor has 1.5 gallons on it and is just not running very well at all. You can turn it over by hand, but barely, which I think is the root of my problem. The motor idles for day and everything is good to go. The needles are now set to flush both the HSN and LSN. Nice crisp low idle to it. The thing has no power to it at all!!!!!! It really bogs on the LSN and is really rich! I try to lean it out an hour or 2 and it starts pinging like it is lean!!!! Problem is driving it on the track it has no bottom to it!!!!!!! Does not have a very strong top to it either. Even with these conditions it is temping at 260. If I lean it to race trim on the bottom it will get up close to 300 pretty quick. I have ran, and ran, and ran this motor at its rich settings and 250 and it never really wants to get any better!!!!! I take my 3 other motors, drop them in with same clutch, pipe, tank and lines, and they scream at 220! I can tune anything and am sort of puzzled. I know it is not clutch, tank, fuel lines as they are all new other motors run great!!!!! I have inspected front bearing and see no signs of leakage.

Should I keep running it now they way it is and eventually it will loose more pinch and problem solved?????? I ran it for an hour straight last night and never improved, still really tight!!!! I think I can't get rid of the pinch, I know it is unbelievable but 1.5 gallons and I really cant turn it over by hand??????? This one is going to need a new rod if it ever breaks in.

Any thoughts by the Nova experts???????


Nova C5tgc (for Break-in)
Byron's 30/11%
Nova 9886

Your fuel has varnished up inside the engine

Usually doesnt happen with byrons but if you idle for long periods of time at temps too low for break in it will happen

By chance r u using some funky aro?

Well, possibility, I only took off the back plate and it looked pretty clean inside. It has not sat more than 7 days at a time without being ran. I guess I should tear it apart and clean everything really good and try again?

I see what you are saying, the only monkey in that wrench is the fact that I use the Comp heater every single time I start it and do not think the motor has ever been below 200 though? Only time it idled for extended periods was first tank I let it idle all the way through, bc the motor was so tight!!!!!

Just my opinion, but I have stopped using them unless motor is going to sit for a month or so. I have not put a single drop of ARO in the Nova.

if a engine has a good dose of leftover castor oil inside the comp heat can bake that oil into a varnish .... I have seen it happen quite often with some fuels, however I have yet to see it happen with Byrons.....

I would consider the possibility of a mechanical issue, and would recommend doing some part swapping to see if you can isolate where the issue may be..Providing you have the parts resource to do so......You could have a cracked case, bad bearing, bad carb etc..... Fortunately there are not too many parts to these engines so its not a hard process to isolate where the issue is coming from.....