Wideband O2 Tuning
05-05-2009, 12:30 AM
#21
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I believe I have read where ethanol has properties that prevent (better than straight fuel) detonation. That is if it is fresh and not full of water obviously. I have a place close by where I can get straight gas but I have been a little hesitant due to reading this. The sc engines have been running great on 93 oct ethanol e10..
05-11-2009, 03:41 PM
#22
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I nice thing about the ability to measure is you don't have to make the engine overly rich except at higher RPM's to WOT. We expect to finish polishing on our 1150 Dominator's jetting next week. In the boat, we expect to be at about 12-6-12.8 at 5500 RPM to WOT using 3.5 PV's. From 3000 - 5500 RPM (PV's closed) our target is 13.6-13.8. At idle in gear, we should be at 14.5-14.7 by changing the idle air bleeds. We also check the plugs after a 2-5 min mid-range run and then stagger jet until the plug color is equal. With our set up we will be 2-4 jets smaller in the front.
What are others doing? I feeling like we are still wasting fuel in the mid-range.
What are others doing? I feeling like we are still wasting fuel in the mid-range.
The O2 tuning was mostly a bust this weekend. We did get the timing set and tested the AFR at idle. We changed the idle air bleeds from 51 to 49. That richened the AFR at idle to about 14.5...hard to be very accurate at idle with big cams as the gauge fluctuates a lot.
Now the water test. We couldn't get on plane as we think we may have an issue with one of the new Crane HI-6 ignitions (winter project). It could be an installation error but we didn't find any issues. From 1000-4000 RPM at the dock, everything including the advance curves was just as expected. The throttle response was crisp and everything seemed right. The idle in and out of gear was sweet....no stalling. We went out in the river and never got on plane. The Stb engine backfired and quit at 2000-2500 RPM coming on plane under load...WTF! Tried twice but something was wrong....idled back to the trailer.
Carb and fuel systems seem fine. Checked and rechecked the Crane wiring Port vs. Starboard and didn't see any issues. The fuel pressure was 6.5-7 lbs and the HI-6 boxes worked fine up to 4000 RPM at the dock. As this issue only shows under load,
is it likely the coil? There wasn't enough time to switch components engine to engine.
Today, I found and ordered a new Crane 6000-6462 marine box and LX-92 coil. We will be ready to parts swap in June as needed. Does anybody have any suggestions of where to look for additional ghost on my June trip?
05-11-2009, 06:57 PM
#24
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14.5 is just at idle at the dock. The AFR is where it is set at13.5-13.6 in the mid-range. It isn't possible that the starboard carb has an issue, but it doesn'ts seem likely. Thanks for the thought, we will swap carbs for one of the test.
05-12-2009, 10:34 AM
#28
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Here is the current plan pre-launch:
1. Check the Stb plugs (If typical move on)
2. Swap carbs
3. Install new Stb coil
4. Water test
Results:
If no back fire, it was the Stb coil. If the Port backfires it is a lean carb (assumes FP is good). If the Stb still backfires, it is likely the ignition box.
4. Change out the Stb ignition box and retest.
Stb still backfires?....make offers
1. Check the Stb plugs (If typical move on)
2. Swap carbs
3. Install new Stb coil
4. Water test
Results:
If no back fire, it was the Stb coil. If the Port backfires it is a lean carb (assumes FP is good). If the Stb still backfires, it is likely the ignition box.
4. Change out the Stb ignition box and retest.
Stb still backfires?....make offers
05-15-2009, 09:21 AM
#29
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I got the boat on the water yesterday and did a little tuning. I found the boat liked 13.5 at idle all the way up to 3400 RPM. I did not test WOT yet. I will post updates on my other post Roller Cam Upgrade.
05-15-2009, 11:12 AM
#30
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Here is the current plan pre-launch:
1. Check the Stb plugs (If typical move on)
2. Swap carbs
3. Install new Stb coil
4. Water test
Results:
If no back fire, it was the Stb coil. If the Port backfires it is a lean carb (assumes FP is good). If the Stb still backfires, it is likely the ignition box.
4. Change out the Stb ignition box and retest.
Stb still backfires?....make offers
1. Check the Stb plugs (If typical move on)
2. Swap carbs
3. Install new Stb coil
4. Water test
Results:
If no back fire, it was the Stb coil. If the Port backfires it is a lean carb (assumes FP is good). If the Stb still backfires, it is likely the ignition box.
4. Change out the Stb ignition box and retest.
Stb still backfires?....make offers
