Originally Posted by RCNitro13

I have a 4BTTS which is about 7L old. I have never been able to get the tune right. Other Nova's at my track scream down the straight and sound crisp and snappy.

My engine is very rich and not producing power down the straight. If I try to lean it an hour on top or bottom then it lean bogs after a few laps and has that pinging sound when coming into the pits when the bottom is too lean (though not too bad of a pinging).

Ive tried plenty of times going back to factory i.e. 3.5 turns out for HS and 5 turns out on LS, when I do this, again its very rich and any attempt at even the smallest amount of leaning makes the engine lean and doesnt sound or make no where near the same power as the other Nova's (or any other motor) at my track. I would expect a 4BTTS should make the same power.

I noticed in the last race, the engine was rich down the first half of the straight then all of a sudden it would run really really lean and had to back off as it was revving its you know what off! This was consistent throughout the race. Even after changing plugs, it kept of flaming out throughout the day.

Im going to check clutch and swap everything out, but is there any tuning tips or possible known issue?

Originally Posted by Lille-bror

EASY!

You have a defective head button.

Been there myself and Monty gave me the answer

If you haven't got another button borrow one and test it.

Originally Posted by PERROTTO

Put an OS plug in it they said....
It will be fine they said....

Lol seriously though, was yours leaking from plug area or the shim area?

Originally Posted by Lille-bror

Hehe. No. I'm dead serios. Had a Plus4 Team that did the same stupid "lean" bugs when I put a racetune on it.
After I changed the button the engine ran perfect again. I still don't know what was wrong with the button: No leaks from the plug etc etc.

Please read this old post:

Novarossi fault finding

Originally Posted by PERROTTO

Yes I've been through the exact same circumstance with a similar setup. Friends p4c team 30/9. Had very unstable idle but would stay running on the box, throw it down and would flame 5-10 min later. Went through engine, carb, and entire fuel delivery system. All checked out ok. Come to find out, he admits he used to run OS plugs. BINGO. New head cured the engine.

I posted pictures of this button a while ago

Originally Posted by RCNitro13

Ive always used Nova plugs. Surely the button couldn't be defective from factory?? Or can some type of misuse cause it to disfigure/warp?

Lets say it is the button (I'll check in the coming days), could this defect cause other issues e.g. on top of the piston?

Originally Posted by RCNitro13

Ive always used Nova plugs. Surely the button couldn't be defective from factory?? Or can some type of misuse cause it to disfigure/warp?

Lets say it is the button (I'll check in the coming days), could this defect cause other issues e.g. on top of the piston?

Originally Posted by PERROTTO

Yes I've been through the exact same circumstance with a similar setup. Friends p4c team 30/9. Had very unstable idle but would stay running on the box, throw it down and would flame 5-10 min later. Went through engine, carb, and entire fuel delivery system. All checked out ok. Come to find out, he admits he used to run OS plugs. BINGO. New head cured the engine.

I posted pictures of this button a while ago

Originally Posted by PERROTTO

If you click the link Lille-bror posted above you will see a quote by Houston saying what to look for if you have a plug that cross threaded/crooked and not seating correctly. The button could most certainly be defective from new, nova is not perfect. But your engines issues sound a little different than most button issues I've come across.

Originally Posted by RCNitro13

The threads and seal seems OK?

As I was taking off the clutch, noticed both bearings were shot, the front bearing completely fell apart! Could the bearings be the cause of the issue?

I think I'll get a new button just in case.

Originally Posted by THE PHILLY JYNX

Post up a pic of the piston out of the sleeve. From the looks of all the stuff stuck to the head button your gonna need more than a head button.

Originally Posted by beidle99

I think you might want to find a new fuel. Can you get Byrons? I run the balls off my engines and run them at a high temp (my plus 4 anyway) normally around 270 to 280 and even after a solid 8 gallons I never saw rust build up like that, always a golden color and a nice coat of oil. Are you running it out of fuel and letting it sit some place that is not conditioned like a garage or shed?