WartedEmperor

I was going to try to fly my Seamaster for the first time yesterday. I could get it tuned on land and it would go through a whole tank perfectly. Then I tried to put it in the water and every time in about 30-60 seconds the engine would bog down and die. I tried readjusting it five times and it would be ok on land till it went in the water. What is making it cut out when it is in the water? Also this is my first sea plane and are you suppost to do anything special to the engine such as tuning or something I should know?

P.S.
My engine is an O.S. .55 AX with a 12x8 Master Airscrew K-Series propeller.

mscic-RCU

My Feedback: (6)

that sure is weird. is it picking up water spray? can't imagine what else it could be unless it can't swim! just kidding.

DLVS2FLY

Is this a new engine, or one that you have run in another plane????? I also think that you have to big of prop for that engine, could be some of the problum!!?----engine settings are the same on or off the water, nothing special.....
Have you checked your tank to make sure everything is still the same, and nothing has changed?? is the engine dying at idle, or when you try and run it up??? you may need to work on your mixture settings a bit more, (low end)
Hope this helps a bit

WartedEmperor

This is the fist plane this engine has been on.

I have already called O.S. about the propeller size and they said that was the one to use, because I thought it seemed to big too. They said that is the propeller that is suppost to be on there.[sm=rolleyes.gif]

The engine seems to be dying at about half throttle after already taxing for a while.

Also I already checked the fuel tank it is fine.

If it is my mixture then why is it not dying on land? It runs like a champion on land!!!

A person I know had a idea that maybe the little bit bigger propeller on this plane is kicking up just very fine mist which the 11'' propeller would not do. Also we thought that maybe the engine is making a fog from the engine heat and the the water. Do you think this could be happing?

I have a video of it dying but it is on this new camcorder we just got so it might take me a minute to figure out how to get it on the computer.

Jburry

Without more details I can only guess, but unless you've spent some time adjusting the idle mixture, I'd bet that the idle needle is set a bit rich. My AX46 was rich by more than half a turn, resulting in a very rich mid-range and flame out on throttle up. The prop doesn't seem too big to me, but some tach readings would tell. Should be turning it in the 11000-12000 range, generally.

How long do you run it at high idle on land? Usually we are focused on high end when running engines in on land.

These engines are VERY tolerant of a little water spray and mist. This is not likely your problem.

If you suspect the prop is too heavy, that is if it's not turning above 10k, try a 12-6 or an 11-8. I'd use the 12-6 for better thrust, over the 11-8.

Try adjusting the low end needle. Actually, try testing on land first. Start the engine, run at idle for about 30 seconds, pinch the fuel line. Engine should speed up briefly, then die out. If it doesn't speed up, it's too lean, if it speeds up for quite a while, then dies, it's too rich. Also, if too rich, idling a minute or so, then whacking the throttle open will cause cough/hesitate and or die instead of a clean transition.

Good luck,

J

jrf

My Feedback: (551)

The 55 has a flat spot at the transition (just above half throttle) where it goes rich. It is a known problem and Hobby Services is bringing in new carbs to solve it.

If you set the idle a little on the lean side and use a good hot plug like the OS #8 that comes with it, the engine will run through the flat spot and pick up again, but if you are a little rich on the idle and then let it idle for a while, it will die at the flat spot.

Water is not your problem. Longer idling while you taxi out probably is.

If you fly mostly at full throttle, you won't notice the flat spot much, but if you fly much at half throttle it is very annoying.

Jim

WartedEmperor

Thanks for the help. I will try retuning the engine this Sunday to see if I had the low end to rich or lean. I will tell you how it goes Monday. Also when are they coming out with this new carb? Another thing what do you consider a long idle?

jrf

My Feedback: (551)

The website now says Late June for the new carbs.

It should idle for more than a minute and then accellerate instantly. Set the idle mixture control screw at the leanest setting you can and still have the engine accellerate without quiting.

Jim

JimCasey

My Feedback: (1)

I was fooling with a guy's OS.40LA, It wouldn't run reliably at all, particularly idle. Field-stripped the carb to check for dirt. nothing. He took it home and removed the engine from the plane and found a LOOSE BACK PLATE. I have also seen weird effects from a loose carb barrel guide pin. Things you would not normally suspect.

WartedEmperor

I think it had a air leak so I took the engine completely apart, and put it back together. Now the engine runs great.

So here is how it went when I got to the lake with the engine fixed. I was doing some high speed taxing to get the feel on how it handles on water, and this wave knocked the wing tip float off. So I swam out to get my plane and when I was pushing it on the dock the battery came unglued in the front compartment. I did not have any glue so I am going to fix it tomorrow and fly her again on Wendesday.

The wing tip float came of easier than what I expected by reading post about it. I saw that some people glue it on to the wing, but I do not want to do that because I want take them off so I can fly of from land. I was thinking about putting a whole strip of velcro, but I don't know how much better it will make it. What do you suggest so I can take the float of when flying from land?

P.S.
I know you are going to say ditch the landing gears it is a seaplane, but I really want it to be able to fly from land.

Jburry

Ya could try placing a ply plate with t-nuts in the wing bay, securely anchored to the spar, le and te, and bolt on the floats...

Some fly off grass with the floats in place... They just are careful to level the wings.

J

WartedEmperor

Today I flew the Seamaster to about 4 feet of the ground trying to get the feel for how it takesoff. Does it come in alot slower than when you takeoff, because it seemed like I was having to go fast before she wanted to lift off?

Jburry

Never flown a seamaster myself, but the ones I've seen land at fairly typical sport plane speeds... Nothin' too hairy.

On take off you tend to be at full throttle, so the plane accelerates very quickly after lift-off... Makes it seem fast. Landings properly executed (on land or at sea) are done just below the lowest sustained level flight speed the plane is capable of... Thus the flair.

J

Tommygun

My Feedback: (2)

Yeah, I think they do takeoff faster. It takes longer to accelerate on water than on land, plus I think you have to get enough speed in order to generate enough lift with the wing to overcome the surface tension of the water. It will make nice slow approaches due to the fact it has a very thick airfoil. Here's some video of mine doing touch and goes...does that look similar to the way yours flies? http://www.youtube.com/watch?v=gqfhkHd2fB4

Carlos Murphy

My Feedback: (72)

Assuuming "running OK on land" means the plane is not moving... static ?

Put the plane in the water or on land and advance the throttle and once the plane starts moving your putting a load on the engine, sounds like it may be running lean.

What fuel and plug are you using? Any 15% (synthetic oiled) fuel and a good plug like OS-F, Enya #3 or alike is recommended.

Is the engine bogging down before stopping or dose it stop like someone turned off the switch? One is rich and the other is lean.

I had a SeaMaster with a OS 50-AX and it was great, water getting in the engine on take-off is never a problem with these planes.

C.M.

NOT A WHEEL HACK

Mostly , I think you have to pay attention to the fuel flow. You could adjust the throttle
and even the mixture many times over and still have the same result. You have to
consider that water not only always effects the temperature of the air , but it also
produces moisture above the surface , which is what you see when you see fog
just above the water line on lakes. Condensation is building up in the line between
the heat of the engine and the cooler fuel from the tank. You have to force your
fuel to take up the space where the condensation is occurring. If you have a slow
fuel flow setup , like a straight across line , condensation bubbles will form in the
line right at about 2 inches away from the heat.

Years ago this happened to me in my car. I had just installed a Holley 650 double
pump carburetor on my freshly , fully machined 1969 383 engine. I had a 400
crank and a purple shaft cam in it . It was meant to be able to withstand high
speed heat. As most of the northern runners were running Offenhouser towers
with dual 750 Holley carburetors capable of running at 120 mph with no problem.

I had just installed the unit , brand new , and it had cost alot. While running back
to the speed shop the engine caught fire , sending slow flowing flames out through
the double hood scoops on the Super Bee. I stopped the car and took my T-shirt
off right in the middle of the road and put the flames out before there was any
damage at all. Luckily , I got it restarted and pulled into the parking lot of the
speed shop , only to have the service tech tap the floats of the carburetor with
a screwdriver a few times and any of the sputtering stopped immediately.

What had happened was that the floats were not set right at the manufacturer ,
they were too tight. And the heat had made them stick that much more. So ,
the throttle was wide open while at 30 mph on a 2 lane roadway in town. The
tech opened up the carb and reset the floats so that they were able to move
freely within the reservoir cavity of the carb. Nothing ever happened after
that. That is obviously a critical part of the fuel flow system , the floats
dictate how much fuel is available to the carb and are connected to the
actual throttle inkage which moves the floats. This brings up the need for
a secondary fuel reservoir within the fuel line delivery system. It is just
as important as any part of the fuel line or tank. And that happened even
though I had also just previously installed an Edelbrock High Rise Aluminum
Intake. It had been cool as a cucumber , but condensation was enough to
make the floats stick considerably. I breathed a sigh of relief when nothing
happened and never trusted anything to chance ever since as I had been
over every inch of that entire engine setup and had not touched the carb
inside. In fact , old single barrel carburetors clearly showed the float bowl
on the front of them , which was always located at the front of the carb ,
where it could keep cooler without any obstructions nearby that may heat
up for that reason.

Another thought is to consider that all car engines emissions and carburation are set
to the sea level at which it will be operated at. For example : California vehicles are
set different from vehicles that will be operated in Canada or further east where there
is more moisture in the air , by the manufacturer before it is shipped or used.

In conclusion , you should make double sure that you have the most positive gravity
on the fuel feed line and if that seems to work , try adding a small bubble reservoir
in the line , directly before it enters the engine. This will give you positive fuel flow
and stop the sputtering which is mostly always related to fuel flow , not moisture.
An inline filter will do the same thing as a bulb reservoir.

Hope you catch a buzz in your engine on the water.

NOT A WHEEL HACK

old bird

WE, the last poster is on the right track. In my meager seaplane experience I have noticed that the engines are always mounted in a pod mounted above the wing. On my two seaplanes this resulted in the fuel tank being crammed into the pod with little or now foam padding. This, combined with the pod sitting on top of a piece of semi hardwood results in a lot of vibration effects on the fuel. If you get bubbles in your fuel line, tuning is impossible. I cured a similar problem in my GP Seawind by mounting the needle valve on the firewall and opening up the nacelle to allow for some foam padding. I just purchased a Seamaster kit off of ebay and am looking forward to further flight reports from you.

Hope this helps, old bird.

jrbackus

Hey all, I just finished putting a Seamaster together last night and have a few questions. First, what is your AUW ( wet and dry??). I weighted mine last night and it was exactly 7.5lbs DRY. From what I'm hearing this thing has enough power to handle the extra weight. I also put a .55AX in it so I'm thinking it will be just fine but I thought I would ask. My extra weight came from the bigger engine as well as I put a 16oz tank in it (the 10oz-er wasn't going to cut it for the 55). I also had to build a new nacell to fit the larger tank which added a couple ounces.

I'm flying it next weekend and I'm going to bring a .46AX allong with me just to see how it will fly on that too.

Thanks for the info!!!

--Jeremy

WartedEmperor

I am cannot weight to find out if some of these ideas will work since I have been at the beach for 2 weeks and the seamaster is in the garage at the lake house so I have not been able to try these ideas.

Thanks for telling me to add positive fuel flow on the tank, but how am I suppost to do that when it is in a pylon with not much movement to get the positive fuel flow. Right now I have a strait across fuel line, but do not know how to make it mositive in the engine pod. What do you recommend to do this?

jrbackus I don't know about adding that bigger fuel tank. I thought about doing that and I was affraid that added weight of the 6oz of fuel and the added weight of the O.S. .55 AX would make the model want to roll over in a turn since that is much higher than the CG.

jrbackus

Yea, I thought about that too. We'll see, i'm not expecting too many problems...

WartedEmperor

If it flies without a problem with the bigger tank and I get the fuel flow fixed on my Seamaster I might do that to mine, because if I remember correctly I will only get a 9 minute flight according to the engine manual.