Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

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Mossy Cypress
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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by Mossy Cypress » Tue Feb 26, 2019 8:00 am

Damn sliding you hunting with that load?

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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by John Fenner » Tue Feb 26, 2019 10:16 am

I just found the cooling shroud kit I knew I had somewhere, all parts and hardware. If you are interested.
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Slidin Gator
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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by Slidin Gator » Tue Feb 26, 2019 7:32 pm

Mossy Cypress wrote:Damn sliding you hunting with that load?
We were this weekend, myself and 3 other guys plus 3 dogs. My son had the mud boat so I was not hauling the whole crew all day. We would park the mud boat and then I would haul the crew up a mile or so and they would walk the dogs through the high ground while I shadowed with the boat to cut off any hogs making a break for it into the marsh. Luckily the water was perfect, 1 inch deep with just some dry (brown) ground to run.

Got 3 nice fat milk sows, my favorite, it was a great hunt! 2 Big fat black ones that looked like twins:

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Here is my catch dog Roscoe and Bay dog Bo doing their thang on How Now Brown Sow:

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I have a plan underway to resolve any need for an overloaded boat in the future. I recently bought a new 14' high sided Stossel Hull, a sister ship to my present boat. I think this one is gonna be the "Grey Ghost." So over time we will have a set of boats to run with.

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I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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Slidin Gator
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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by Slidin Gator » Tue Feb 26, 2019 7:34 pm

John Fenner wrote:I just found the cooling shroud kit I knew I had somewhere, all parts and hardware. If you are interested.
John,
I am interested, is it configured for straight valve Lycoming cylinders? I will have to modify it to clear the Pacemaker ignition, but it would make for a good start for me.
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by John Fenner » Wed Feb 27, 2019 8:45 am

Yes it is for a pv
I never finish anyth,,,.

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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by Mossy Cypress » Wed Feb 27, 2019 9:08 am

Awesome sliding! I miss running them hogs, glad to see somebody still giving em hell, looks like a great time. Your boat runs great man that's quite the load, thanks for sharing the pics.

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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by rowdy1 » Wed Feb 27, 2019 6:30 pm

Slidin Gator, Once again you and I may be related. Check out the little jewel I got. It is a cut down airgator with a 0290. Soon to be upgraded to something a little meaner! It goes fine now but the former owner had a wide deck 180 on it and it was a handful.
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Slidin Gator
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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by Slidin Gator » Wed Feb 27, 2019 10:43 pm

rowdy1 wrote:Slidin Gator, Once again you and I may be related. Check out the little jewel I got. It is a cut down airgator with a 0290. Soon to be upgraded to something a little meaner! It goes fine now but the former owner had a wide deck 180 on it and it was a handful.
There is a good chance of a common ancestor or two, my family tree looks like a vine anyway. :lol:

I see an IO360 in that boats future!
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by kwanjangnihm » Wed Mar 13, 2019 4:36 pm

Slidin Gator - any updates on your temp, carb & timing issues?
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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by Slidin Gator » Wed Mar 13, 2019 8:54 pm

kwanjangnihm wrote:Slidin Gator - any updates on your temp, carb & timing issues?
No change since last, work has had me all over last 2 weeks. I bought the used Heat Extractor shroud from John and I have started modifying it to fit around the Pacemaker Ignition, it's cut to fit and ready to weld now. The plan is to see what that does next week when I go down to ride with Radtech at Mack's. Once we get my Q fitted to Rad's boat tomorrow we are both headed to the airport for a several hundred gallons of awesome smelling fuel. :bounce:
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by Slidin Gator » Mon Mar 25, 2019 8:09 pm

Latest update.

Got the shroud modified and fitted last week. They say you can either get good at welding or grinding, I do pretty good on steel but with my aluminum spool gun do a lot of grinding (could probably use some bondo too :( ). Regardless, mods complete and installed. I did not install the lower baffles yet, just the shroud. The electric cooling fan is removed, just prop driven cooling.

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Spent the last 4 days at Mack's with Radtech riding Areas 2A & 2B. That place is usually pretty easy on the motor. Temps on all cylinders ranged 400-475. At least until Saturday :shock: Pulled Radtech's 16 foot Caddy boat 7 miles to the nearest levee, turns out AV boats can tow CM boats. Towing that barge in 6" of water was about the same as running hot green sticky nettle. Under that condition 5 out of 6 cylinders stayed under 500, but #4 was hitting 550 before I would stop to cool it down. Oil temp was barely making 150. At this point I can definitely say that I have made a lot of gains, my oil temp runs way cooler than it used to (too cool really), so I can't imagine what my cylinder temps were before I started digging into this. I plan to install the baffles to see what they do, that should further improve the center (#4) cylinder with cooling.

I mentioned in an earlier post that I thought I had a sticking exhaust valve, the motor stumbles and sucks irregularly from the Port exhaust during warm up, but has run good under load. This trip it started the occasional miss while running under load, just enough for a quick butth@l$ pucker before back to business, have another sip. After the long tow Saturday it was a 10 mile run to beat sundown and the motor started acting up more regularly with a few short periods of running a 5 cylinder motor!

It appears to me that I have sticky exhaust valves on both #2 and #4 cylinders. I'm trying to decide which way to go here, I have spare rebuilt cylinders on hand and the motor has had a bit of a morning stumble since these cylinders were installed 40 hours ago. I am thinking that perhaps the guides were a bit tight originally and need to be reamed vs. just carbon cleaned.

My goal is to be back running for Friday. Does anyone have a different diagnosis or recommendation before I spend the day tomorrow swapping cylinders while I should be working?
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by Seadrift » Mon Mar 25, 2019 11:37 pm

WOW elaborate, totally cornfused, that's like computerized race car diagnostics
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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by One Eyed Gator » Tue Mar 26, 2019 8:34 am

Have you ever verified TDC is reading correctly on the pacemaker?

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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by Slidin Gator » Tue Mar 26, 2019 11:22 am

One Eyed Gator wrote:Have you ever verified TDC is reading correctly on the pacemaker?
The pickup is aligned with the set screw at TDC, but it would be nice if there was some way to confirm that the computer is signaling TDC at that point. Is there a specific procedure you are aware of?

I will note that after all the other changes (cooler spark plugs etc.), I am not seeing any noticeable difference in cylinder temps when switching timing between 22 and 25 degrees advance. The plug change (Autolite 373) appears to have made the most difference and the color of the cooler plugs looks about right to me.

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I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by One Eyed Gator » Tue Mar 26, 2019 11:44 am

No sir I do not. It was just a thought.

Also the AFR sensors do not like leaded fuel.

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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by Hardtail » Tue Mar 26, 2019 6:37 pm

Slidin Gator -- Have you checked your Exhaust Gas Temperatures? I think that the EGT is the best information to find out if your running lean on each cylinder before it shows up on the CHT, too lean shows up first on the EGT, then the CHT rises if too lean, My 0-360 runs about 1700* EGT with the CHT about 550*, then to keep it from shock cooling I always let it idle till the temps drop below 400 and EGT drops to the bottom of the gauge then shut down.

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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by Slidin Gator » Tue Mar 26, 2019 7:06 pm

Slidin Gator wrote:
One Eyed Gator wrote:Have you ever verified TDC is reading correctly on the pacemaker?
The pickup is aligned with the set screw at TDC, but it would be nice if there was some way to confirm that the computer is signaling TDC at that point. Is there a specific procedure you are aware of?
Duhh, I can check the timing with my timing light to confirm what I see on the screen matches reality...
One Eyed Gator wrote:No sir I do not. It was just a thought. Also the AFR sensors do not like leaded fuel.
Understood on the AFR sensor, that, plugging up the cats were drivers in eliminating lead from the auto fleet. It is just a test item for me, it won't be permanent mounted.
Hardtail wrote:Slidin Gator -- Have you checked your Exhaust Gas Temperatures? I think that the EGT is the best information to find out if your running lean on each cylinder before it shows up on the CHT, too lean shows up first on the EGT, then the CHT rises if too lean, My 0-360 runs about 1700* EGT with the CHT about 550*
Hardtail, understood but no I do not have EGT sensors installed and I probably won't, this is enough of a science project for me already. My IR gun does not go high enough to measure the exhaust either. I may make up an EGR test sensor/gauge package but probably won't run it, it's hard enough now to scan all my gauges and keep from crashing at the same time!

You are actually the first comment on this thread to note CHT temps similar to mine (above 500). I am slowly coming to the conclusion that I have the tuning about right and temps are what they are. I also have an issue on #2 & #4 which I am pretty sure is related to the exhaust valves (sticking valve or moving seat). I am in the process of yanking these 2 cylinders and swapping them for two refurbed cylinders that I have on hand (new chrome). Goal #1 is to boat back running before the weekend, then I can inspect the 2 cylinders, fix whatever is wrong with them and put them back into the spares stash.
Hardtail wrote:then to keep it from shock cooling I always let it idle till the temps drop below 400 and EGT drops to the bottom of the gauge then shut down.
You're procedure is certainly a good plan, although I freely admit I violate that a lot. When running and hunting with dogs I do end up doing quick shut downs at times, but that's the price of admission, I will sacrifice a cylinder to save a dog! I believe the Lycoming operators manual calls for a minimum 25 degree drop in cylinder temp before shutdown and I know that assumes the cylinders are under 400 to begin with. Plus, the damn car motor guys always try to talk to you before you give the motor time to cool down. :stirpot:
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by rowdy1 » Tue Mar 26, 2019 8:24 pm

Gator,
I have almost finished installing the fuel injection on my 520. I was talking to Joey at Southern Fuel Solutions about tuning this afternoon, he says we need to be chasing a 14.8 AFR.

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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by CarMotorBarge » Tue Mar 26, 2019 8:29 pm

The car motor guys are talking to you because they beat you to the spot. They have already cooled down and shut off their engine. :stirpot:
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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by Hardtail » Tue Mar 26, 2019 8:44 pm

Slidin Gator - Looking forward to riding with you again this weekend, hope you get it back together in time, last week end was a great ride,

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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by Slidin Gator » Tue Mar 26, 2019 9:11 pm

rowdy1 wrote:Gator,
I have almost finished installing the fuel injection on my 520. I was talking to Joey at Southern Fuel Solutions about tuning this afternoon, he says we need to be chasing a 14.8 AFR.
That's pretty much optimum for power and is probably what I would be thinking for a race boat or quick blasts. But that sure seems on the lean side for keeping the motor cool under continuous heavy load. By that measure I am plenty rich. At some point I do plan to swap back to the M4-5 carb and compare AFR vs. the 6AA at full rich, then try a bit leaner on the economizer and see what happens with CHT. Just trying to do one thing at a time so I know what effects what. At this point it looks like I'm going to be breaking in 2 new cylinders so max rich is what I'm gonna need for a bit.
CarMotorBarge wrote:The car motor guys are talking to you because they beat you to the spot. They have already cooled down and shut off their engine. :stirpot:
Depends on the car motor boat :D
Hardtail wrote:Slidin Gator - Looking forward to riding with you again this weekend, hope you get it back together in time, last week end was a great ride,
That's the plan, hope to see ya there :thumbleft:
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by rowdy1 » Tue Mar 26, 2019 9:31 pm

BTW, I watched the video you posted. My old wide deck 180 sounded like that and it had a loose valve seat. It ate its self one afternoon on the way back to the ramp and required a new cylinder and a pushrod.

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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by Slidin Gator » Tue Mar 26, 2019 10:30 pm

rowdy1 wrote:BTW, I watched the video you posted. My old wide deck 180 sounded like that and it had a loose valve seat. It ate its self one afternoon on the way back to the ramp and required a new cylinder and a pushrod.
Thanks for that input Rowdy, it helps confirm I’m not wasting time tearing into it. I think I was close to eating a valve going to the ramp this weekend.

I have been thinking sticky valve, but I just don’t have the hours on these cylinders for the carbon to build up. I talked with Steven Jurnigan today and the loose valve seat seems like the more likely cause. In particular #4 since it has been the hottest.

Hopefully new valve seats will sort them out and then all my spares will be broke in.
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by John Fenner » Wed Mar 27, 2019 10:58 am

Meant to comment yesterday but got called out to a fire, was going to say, loose seat which will eventually drop out.

In order to remove seats, the cylinder head needs to be heated to 600°F for a constant 5 minutes, a sized washered wet sponge on a handle will shrink the seat and pull it right out, kinda the same scenario on a hot shutdown, valve shrinks the seat, crank it back up, it pulls seat out or let's it fall out a bit, valve and spring pressure pulls it back in eventually but it is now loose, swap it out.
I never finish anyth,,,.

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Re: Tuning a Lean Running O-540 & 6AA / M5-4 Carbs

Post by Slidin Gator » Wed Mar 27, 2019 12:02 pm

John Fenner wrote:Meant to comment yesterday but got called out to a fire, was going to say, loose seat which will eventually drop out.

In order to remove seats, the cylinder head needs to be heated to 600°F for a constant 5 minutes, a sized washered wet sponge on a handle will shrink the seat and pull it right out, kinda the same scenario on a hot shutdown, valve shrinks the seat, crank it back up, it pulls seat out or let's it fall out a bit, valve and spring pressure pulls it back in eventually but it is now loose, swap it out.
Thanks John, given what I know now, at least #4 cylinder has already gotten the 600 F for 5 minutes treatment multiple times, should be easy to remove :blackeye:
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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