thanks for the tips! there is a brand spankin new clutch set up and collet on it, waiting for the new orings from RUNNE to get here. give them a try and see what happens, thanks

i think 240.00 is a bit high, there is a combo on there now with 2072 pipe all restrictors, extra rod, 2 turbo plugs, and extra shim all brand new for 165.00 with free shipping.

Hey guys, this is my very first post on the forum. I would like to thank everyone in this thread for asking and answering some great questions. By just reading through and keeping up with the new and old post I have been able to tune and run my GO engines without any problems. Well, until recently. Not really a problem but more like just confused. Here's the deal, since day one of the purchase of my GX5, GX7 and MG66,s I've only run Odonnell 97t plugs as per what most recommend and they all have performed flawlessly. Just for S&G's I put an OS P3 in and "WTF", my engine started running rich and wouldn't clear out. My temps went from an average 255* and running like a scalded dog to 205* and running like a dog. All this was just from a plug change and not messing with the needle settings. After a retune (3 hrs. in on top and 1 hr. in down low), I felt as if I had a brand new motor. Ended up having tons more bottom end and loads more top end that wouldn't stop. Another thing is that my head temps went down to 245*. I have since done this to all of my engines and the results were all the same. Not complaining or anything, just looking for an explanation as to why putting a hotter plug would cause me to lean the needles an have more power with lower engine temps.
more power-lower temps-longer tank times

BTW: Shim stack is .4 (1 silver and 1 copper) on A-Main 25%

Changing the plug "heat" adjusts the timing on the motor, hence re-tune.

As to why the power increase, I'm listening.

Could be the engines are starting to loosen up too as well as the new tune to suite the earlier timing.
I too used to run OS and RB plugs but are too expensive here in Aus compared to the OD and I didn't find much change in performance within the same heat range, most of us run medium heat range as a rule but I too have run a hotter and a colder range when in a different state.
The key is to find what works for you and where you race.

Yes, I understand that a hotter plug advances timing. What I can't explain is why the lower temps? That was even after leaning the needles, and everyone knows that 3hrs on a GO engine is alot.

Ignition timing determines when combustion occurs in relationship to piston position (measured in degrees of crankshaft rotation).

If timing is retarded, the combustion process may still be occurring when the exhaust port opens. This would cause the exhaust temps to be high while lowering head temps. Advancing the timing would raise engine temps and reduce exhaust temps. So why is your engine actually running cooler? I'd guess that your tune is actually still a little rich.

to me, what u are describing sounds like when i changed fuel brands to A-MAIN !
it would be good to know if it's the plug, or something else like the motor loosening up !
if you still have an Odonnell 97t plug you could change plugs while the motor is hot & see if there is a difference.

+1

Thats exactly what I did, it was an on-the-fly plug swap. Thinking that it was a faulty plug I put a new P3 in and it still had the same effect. I then switched back to a new OD and performance picked back up. Remind you, during all of this I hadn't touched the tune yet. But when I did WOW more power with lower temps. Could it be that the 97t is actually hotter than a P3 regardless of what the package says? The only reason I ask this is because that's what it reminds me of. I figured that after I installed the P3 I would be richening the needles but I actually had to do the opposite.

That DOES sound like just what happens when you're finally fully broken-in. Goes way rich, sometimes quite suddenly. Temps then come down too due to less friction from excess pinch.

So what you are telling me is that all four motors fully broke-in exactly at the same time after a plug change.

DOUBT IT...BUT JUST MAYBE

I din't think so.

HAVE THEY ALL CONSUMED THE SAME AMOUNT OF FUEL?....DOUBT IT BUT IF SOOO THEN YEAH THATS WHAT HAPPEND