gas stablizer & EGT's

Put stablizer in the 572 with the 871 BDS and decided it was such a nice day that I would take the jetboat for a cruise. The air temperature was 72 degrees and the water temperature was at 52.
The boat ran 200rpm's faster than normal during the summer months when the air is usually around 85 to 98 degrees and water is about 78 degrees.
My Exhaust temperature normally is 1250 to 1350 depending one day to the next and the cruising rpm's are about 2500 to 3500.
When I ran the stealth Tue and Wed I noticed the exhaust temperatures were running at 1150 degrees. Even when I stomped it and held it through the 1/4 mile at 6 lbs of boost the exhaust never got above 1450?
Have any of you guys had simialiar experiences when putting stablizer in your gas?
I checked the plugs and normally they are clean but in both instances the p[ugs look rich? I would have expected the plugs to look leaner due to the cooler air temps?
Does stablizer raise the octane level? I thought it was a kerosine base?
Kojac

I have no clue regarding your question but i have a question for you.
How are you measuring egt? Is that an indicator of rich or lean afr?

I suspect you are ignoring temp drop and giving too much atribute to stabilizer. Last fall, took Lowrider out a week after sta-bil'ing her (beautiful weekend). LOST 100 RPM, air temps were comparable (low 80's), water temps (thus engine temps) as well, unknown, but was only about 2 weeks later.
Stabilizer reduces the flash-off of the most volatile (evaporating) compunds in the fuel. As such, while it MAY "increase octane", it will slow the burning rate, and thus, actually reduce power output.

stabilizers and 104 octane boost additives will change the electrode and ceramic color. egts ? maybe the sensor was affected with a film that changed the reading.??

I have no clue regarding your question but i have a question for you.
How are you measuring egt? Is that an indicator of rich or lean afr?
Taylorman : I have exhaust temperature sensor's in the headers. I try not to run over 1350 degrees. It in itself does not indicate whether or not you may be running rich or lean. Normally after a 1/4 mile run in the summer my exhaust go up to 1500 degrees and may be indicating a lean condition. I believe one reason is due to pulling the gas out of the bowls faster than the bowls fill up. Others reasons that contribute are increased rpm's causing an increase in friction and inability to remove heat in the engine adequately.
Too rich will also cause an increase in exhaust gas temperature due to unburned gases igniting in the headers.
SmokinlowriderSS: That was my first thought but I actually increased 200 rpm's over normal summer driving. I believe also that any higher octane slows down the burning rate and reduces power. That is why I am asking the question.
I attributed the higher rpm's to cooler denser air. But when you have cooler denser air you generally see a leaner condition unless you jet up the carbs. My plugs were richer. A leaner condition would also usually increase the exhaust gas temps unless they were already too rich.(Which may be the case) But they normally don't show any signs of being rich. Actually they normally look like I just took them out of the box. I check them each time I go out. Or am I analyzing this all wrong? This is the first time I ever used stabilizer and wondering what effects it has on the engine.
UBFJ: Could be your right. I'm not really concerned. It's not worth changing for the few times I run it in the fall. I'm just curious. This didn't occur in the early spring and or last fall when conditions were similar?
DEL51: Good point I will pull the sensors and check them for residue and clean them and plugs. Going out next week if weather permits. I will run this gas out and check and then run new 93octane to see what changes occur.
Thank for all your input.
Kojac

Several of my customers have reported their boats running better lately (RPM increases), but the ones with EGT's have complained of higher readings. We have just assumed that with the cooler air temps (more dense) that the motors are running leaner. You have found both more RPM and a drop in EGT. Just curious what your timing is like? My pea brain is thinking that if you run a fairly soft tune up (higher EGT's for no reason), your RPM increase is from the slightly leaner mix, but the change in the burn rate of the "stabilized" fuel is having a similar effect on the combustion process as advancing the timing.
However, if you motor was set on kill already, then I am just wrong and dumbfounded, which has happened before...
Just went back and read you last post a little more. If you are reading plugs by color, you are doing it wrong. With the additives and alcohols in todays pump fuel, you will seldom see a color change on the porcelain. I find it much more effective to read the burn line on the ground strap and compare to EGT's if available. If you motor were rich enough in the summer to be washing the plugs (which doesn't take much with dual carbs and a lung), they would look like brand new, and you would see high EGT's because the fuel is still burning as it passes the sensors. Now bring in the aforementioned added air from the cooler temps, and you motor just got a lot happier!

Anyone know what the gas stabilizers really are made out of???
I winterize about 50 boats for storage and hate buying the stuff when I know it probably is something simple, cheap and readily available.
Be good, Jim

Several of my customers have reported their boats running better lately (RPM increases), but the ones with EGT's have complained of higher readings. We have just assumed that with the cooler air temps (more dense) that the motors are running leaner. You have found both more RPM and a drop in EGT. Just curious what your timing is like? My pea brain is thinking that if you run a fairly soft tune up (higher EGT's for no reason), your RPM increase is from the slightly leaner mix, but the change in the burn rate of the "stabilized" fuel is having a similar effect on the combustion process as advancing the timing.
However, if you motor was set on kill already, then I am just wrong and dumbfounded, which has happened before...
Just went back and read you last post a little more. If you are reading plugs by color, you are doing it wrong. With the additives and alcohols in today's pump fuel, you will seldom see a color change on the porcelain. I find it much more effective to read the burn line on the ground strap and compare to EGT's if available. If you motor were rich enough in the summer to be washing the plugs (which doesn't take much with dual carbs and a lung), they would look like brand new, and you would see high EGT's because the fuel is still burning as it passes the sensors. Now bring in the aforementioned added air from the cooler temps, and you motor just got a lot happier!
DUCKY.
The ground strap starts to change just above the edge of the tip of the center electrode of the plug.
My ignition timing is set at 36+ degrees with the sears timing light. I have two 1150' sitting on the 8-71 BDS. The cubic inches are 572.
As you experienced I generally pick up a few rpm's in the spring and fall and contribute it to the cooler denser air temp's. This is the first time I experienced lower EGT's and am curious. After checking my logs I see that I dropped my ride plate in early September.8/10's of a degree and had not had the opportunity to run and radar it yet but am thinking That I might have unloaded the pump a little and in doing so lessened the load on the impeller and motor. I know this would help some in the increase of rpm's. But am unsure if it would have dropped the EGT's Have decided to raise the ride plate back up to it's previous setting just to see if it changes the EGT's. Hope for some good weather this week and will post my findings.
If you are correct about making a happier motor then it appears that I am too rich and should jet down a size or two for summer boating? Am I reading you correctly?
Kojac

Yes you are reading me correctly. I know several guys running everything from hot outboards to blown v-drives that lean the motor down a notch in the summer to compensate for the hot air...But be careful as even though your A/F ratio will be better, you are also compressing hotter air to begin with, which could raise your EGT's even more. I don't want to be responsible for you killing your motor, but on our circle boat stuff we have run EGT's as high as mid 1400's and the burn line up to the first thread on the plug without failure. These are N/A motors though..... One thing I have learned about blower motors in general is that they love timing through the mid-range, but they don't need quite so much under full boost. You may consider adding a boost retard setup and pulling a little timing away from it once you are rolling which will allow you to take a little fuel away more safely.
My initial idea about the "soft tune up" doesn't really appear to be the case, as I was thinking you might be one of those 28degree blower motor guys
Based on your explanation of plug readings, It sounds like your motor is tuned pretty conservative (at todays cooler, denser air), very close in fact to where I would run my own if I were not racing. I would venture to guess that you are right on the line of being over rich in the summer.
Your idea about the unloading of the motor is also a very probable concept. Taking the load off a motor will defintely lower the boost and hence the EGT's