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ANGELOS airboats

It's definitely a big jet size difference. But everyone with these engines and carb are running between 74-78. I have a feeling it was either never rejetted or they put the Jets in when there was that intake leak.

I put the #32 squiter in that was recommended. It had a 28. Also went to remove the brass filter, and there was a wasp in the barb. Must have went in the fuel line while I had the carb off.
I didn't have the trailer hooked up, so I couldn't really get on it. But the throttle response felt much better. So I guess now it's just put some hours on it and see how the plugs look.

What are some symptoms to look for if it's running lean? On the trailer its not stumbling or backfiring
 
Symptoms running lean of peak are usually burnt valves and short cylinder life or overheating.
Best to install a cheap o2 sensor so you're not guessing.
 
ANGELO said:
What are some symptoms to look for if it's running lean?
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If it is running lean you should notice it being down on power.

Hard to describe but when the raitio is off on a carb it is like, it is trying to go, it is making noise like it wants to go, but it won't go. LOL sorry, best way I know how to describe it.

Do you have a tach? If you cannot achieve the same rpms you are lean.

Lean plugs will look white or tan. Way too lean and you may see burnt electrodes.
 
This runs leaded gas. Doesn't that not work well with o2 sensors if I got a gauge?

I put the bigger squirter in like recommended on the airboat page. Over all it feels like it performs the same as before, except my fuel consumption seems to have halfed. Had it out 2.5 hours today. Mostly cruising but also some wot under load, and of course idling.
PXL_20240901_210604685.jpg

Port right rear. That cylinder is definitely burning oil.

PXL_20240901_210210109.jpg

Stbd right front.

Why does the front cylinders run leaner? Could it be because the front runs hotter due to less airflow?
 
Videos not working on my phone but looks like fun.

You should not need leaded fuel by the way. It will screw up an O2 sensor, but I’m assuming you don’t have fuel injection anyways?

Be careful about leaning too much. The engine needs fuel for cooling. I’m assuming you don’t have any cylinder head or exhaust temperature indication correct?

If nothing else, I’d pack an IR thermometer and make sure you’re not seeing pictures of those cylinder heads much more than 400.
 
Bacho said:
Videos not working on my phone but looks like fun.

You should not need leaded fuel by the way. It will screw up an O2 sensor, but I’m assuming you don’t have fuel injection anyways?

Be careful about leaning too much. The engine needs fuel for cooling. I’m assuming you don’t have any cylinder head or exhaust temperature indication correct?

If nothing else, I’d pack an IR thermometer and make sure you’re not seeing pictures of those cylinder heads much more than 400.
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100ll is what I've been running.
I just have oil temp. Probably a good idea to bring a ir gun and check after a hard run.
It was actually running slightly cooler oil temp yesterday compared to last time, but we also had one less person.
 
ANGELO said:
100ll is what I've been running.
I just have oil temp. Probably a good idea to bring a ir gun and check after a hard run.
It was actually running slightly cooler oil temp yesterday compared to last time, but we also had one less person.
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At least on the smaller continentals, 100 low lead has more lead than the engine wants or needs. The airport at my plane came from sold a 25% low lead to 75% Mo gas blend which I thought was a pretty good idea. I would be burning auto fuel if it was more convenient.
 
So in those videos where you are driving a path of water about as wide as you boat, is that all water, but fifty million boats made the path?
 
WaterH said:
So in those videos where you are driving a path of water about as wide as you boat, is that all water, but fifty million boats made the path?
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Most of that mud path was dry ground. I was having to go pretty quick to keep momentum up, that mud is sticky.
A couple boats go over the same grass and it'll stand back up, but once it becomes a trail it'll have to much traffic for the grass to grow.

The airport is like 10 min out of the way so it's not to bad. Probably costs about the same as premium
 
Depending on how long it was to the last rebuild, it may have hardened seats an not need the LL. I'm not sure how you could tell though.
 
Yeah, I would run a compression check on that engine.

At least to know for sure they are all close because that is a big difference in plugs.

You could have a valve adjustment issue but I bet it is worse news than that.
 
Tiha said:
Yeah, I would run a compression check on that engine.

At least to know for sure they are all close because that is a big difference in plugs.

You could have a valve adjustment issue but I bet it is worse news than that.
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I'm going to pull all 3 cylinders on the oil burning side. I should have done all 3 last time. Oh well.
Leak down test maybe show more then compression? If one of the valves is leaking, will that lean it out?
 
WaterH said:
Yes, leak down is better. Not heard of valve making it run lean, but I don’t know shit.
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Ha, I was thinking the opposite. A leaky valve, less compression, that cylinder runs rich. It would pretty much have to be a bad exhaust valve for that to happen.
 
who knows how may hours these cylinders have. Its a conversion motor, so these cylinders arent original. Usually for most of the engine parts people use good parts that are replaced on airplanes to pass inspection.
 
other then the one lean cylinder and the one burning oil, the jetting seems pretty close if i can get all 6 to look the same
 
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