the color looks good, but the pictures resolution is just not there to tell very much...how do the glowplug coils look ? to me they maybe look distorted ?

That engine was running around 290 - 300 all day. I'm worried about the temps but it runs great at those settings. That has to be too hot doesn't it?

nope.....temp really is nothing to worry about usually.........if the engine is not lean and its running good then thats all that matters......

Dual stage idle
 

As the title says what are the propable causes and how does one eliminate them? Thanks in advance for any replies.

Your LSN is too rich, you compensate by widening your idle gap. This will burn off the fuel for a few seconds, once the fuel is burned off tin the crankcase the engine will drop to a normal idle. Lean the LSN until the idle does not drop, then lower your idle.

Some mechanical conditions might cause this but 90% of the time it is the tune.

After you do this you may need to richen the HSN.

yep !!

also can be cause when a engine is starting to wear out..... it will not stay running stable unless its tuned with a 2 stage idle..... many times getting them repinched gets rid of the issue

So, before you lean out the LSN you should richen the HSN so this wont give you more weird tune? Would that be a general advice?

I`m used to O.S. engines, and while basics are the same, they dont tune the same IMO.

No, do the LSN first until you have a consistent idle, then richen the HSN.

Yes, I know what you are talking about!!!! I run OS a lot too besides my Novas and they do tune the differently. The LSN on the OS doesn't really do too much besides at idle. The Nova has a shorter needle on the LSN and tunes a little differently and requires you to get both of the needles in "sync" so to speak.

I would not touch your HSN yet. Lean the LSN until the idle does not drop and stays consistant. Then drop your idle where it should be. If the engine is healthy you should be able to blip the throttle and the engine should return to a normal idle fairly quickly!!!!! Reminder, do this after the engine is warmed up also. Do not try to tune the LSN until it is warm. Then set it on the track and run it and dial in the HSN. You should be close and just make a small 1 hour adjustment at a time to get the HSN where it needs to be.

Which nova are you running? I will disclose this...... I never never temp my engine when I run the Plus-4btt..... I could care less what the temp gun says. I can honestly say it has not seen a race day that the temp gun would have came in under 280!:) It is a short head that reads a little higher and could care less how hot it runs. As long as it is crisp with smoke you are good!!!!!! Never had an engine problem besides a leaking front bearing that had nothing to do with temp and have "multiple" and i do mean "multiple" gallons on the Nova's......:eek:


Many say a good setting on the LSN = 4.5 turns out, HSN = 3 turns out. I am a little but richer than that on the bottom, and the same on the top due to our areas weather, etc.....

My lsn is about 5 turns out and my HSN is a little past 4 turns out. A good sign that your close but a touch lean on the LSN is a slight hic-up coming off idle. sounds similar to a lean bog but very short and the motor isn't smooth coming off idle. When that happens I richen the LSN less then 1 hour and its perfect.

I am at the exact same as you on the LSN. One of the Nova "masters" told me this setting and I found it leaned bog and hiccuped. I am at about 5 on the LSN and not sure on the HSN, but I am barely in from flush I know that.

Also, if your HSN is too lean, the engine will come off the track with a high idle, and if you hit the throttle quick it will return back to a normal idle, but then become high again.

There is no "good setting", an engine will tune different based on its glow plug, fuel, location, wear, pipe, etc. You usually can't get away with using someone else's settings on your engine, too many variables.

Yep, and we all know that and I know that, just using it as general guidelines!;)

CHOPPER HAS SPOKEN!