Loading Flywheel

[Taspiper]

Ive been trying to get my motor as tuned as possible on land before I venture out again, hopefully for not another wasted trip.
The 2 1/2 needle is screwed down around half a turn. Engine seems to run and idle well along with picking up revs well.

As its running in a tank without the prop I tried loading it up by holding a rag against the flywheel.
It still seems to pick up ok with moderate pressure. If the needle is flush with the slide it will tend to bog down so 1/2 down seems ok.
Under moderate flywheel pressure it seems to miss slightly... Maybe..
No load idle it kicks around a little and will slowly turn in the transom bracket, single cylinder I guess. Does this sound normal?
If I really load up the flywheel at 1/4 throttle I can stall it. I'm just trying so simulate some load but don't know what it equates too as far as power to the prop.
Do you think most of this sounds ok?

[Keith.P]

You didn't say why you had a wasted trip, last time?
Transom slowly turn, that can happens on most single cylinders and can be a timing problem, if its too bad.
Can you not run it with the prop on and at the same depth as you would if it was on your boat?

[Ian Malcolm]

All outboards that don't have counter-rotating props suffer from torque steer. Basically the prop blades on the rising side of the prop experience a different amount of resistance to those on the downwards moving side due to the proximity of the water surface and, when moving the asymmetry of the flow off the boat bottom with respect to the rotation.

Your seagull turning in its bracket is NORMAL. Misfiring increases the rate of turning, not because of torque changes but because the increased vibration relaxes the bracket's grip slightly.

[Taspiper]

You didn't say why you had a wasted trip, last time?
Transom slowly turn, that can happens on most single cylinders and can be a timing problem, if its too bad.
Can you not run it with the prop on and at the same depth as you would if it was on your boat?

See other post " blasted seagull" carby problems was the cause. Now I've fitted a villiers carb.
The only tank I've got is 60 litres. With the prop on it empties very quickly. With prop off so I get cooling I was loading the flywheel to get some sort of indication as to weather the engine is running near as possible to right mixture.
As post above I know props walk but with the prop off it still kicks around but I gather this is normal due to firing and rotational direction of a single cylinder.
Just trying to ascertain how much load a prop would put on an engine at moderate revs versus putting some load on the flywheel in simulation so that hopefully I don't have another wasted sea trial.

[skyetoyman]

Surely the answer would be to get a bigger bin. Many over here used a wheely bin. I use a whisky barrel. sadly it only has water in it.
Gyroscopic action is what causes boats to corkscrew through the water. Does it corkscrewing in the opposite direction down under ? The flywheel is OK but the engine parts arn't.
It's the reason that a front loading spin dryer has a big weight one top . A twin tub can spin much faster and doesn't need the weight.
That's what HID says.

[Vic]

Ive been trying to get my motor as tuned as possible on land before I venture out again, hopefully for not another wasted trip.
The 2 1/2 needle is screwed down around half a turn. Engine seems to run and idle well along with picking up revs well.

As its running in a tank without the prop I tried loading it up by holding a rag against the flywheel.
It still seems to pick up ok with moderate pressure. If the needle is flush with the slide it will tend to bog down so 1/2 down seems ok.
Under moderate flywheel pressure it seems to miss slightly... Maybe..
No load idle it kicks around a little and will slowly turn in the transom bracket, single cylinder I guess. Does this sound normal?
If I really load up the flywheel at 1/4 throttle I can stall it. I'm just trying so simulate some load but don't know what it equates too as far as power to the prop.
Do you think most of this sounds ok?

I think you will find that the only way to get the carb needle adjusted to its optimum setting is out on the water at full throttle. That is certainly what i have found!
Can take quite a while to get it perfect adjusting just a little at a time.
For what its worth I have found that to get my Featherweight ( converted to 25:1 with a no 2 needle ) running really sweetly without 4-stroking I have had to wind the needle adjustment down to 3 full turns below flush. In fact it may be just a gnat's lower.

[Keith.P]

All outboards that don't have counter-rotating props suffer from torque steer. Basically the prop blades on the rising side of the prop experience a different amount of resistance to those on the downwards moving side due to the proximity of the water surface and, when moving the asymmetry of the flow off the boat bottom with respect to the rotation.

Very interesting, more so when its running without a prop.
Or it could be down to four stroking and rough running.

[Taspiper]

I think you will find that the only way to get the carb needle adjusted to its optimum setting is out on the water at full throttle. That is certainly what i have found!
Can take quite a while to get it perfect adjusting just a little at a time.
For what its worth I have found that to get my Featherweight ( converted to 25:1 with a no 2 needle ) running really sweetly without 4-stroking I have had to wind the needle adjustment down to 3 full turns below flush. In fact it may be just a gnat's lower.

I agree that's what I will probably do. I'm just trying everything possible first so that I have a chance that the engine will go when it hits the water

[Taspiper]

Surely the answer would be to get a bigger bin. Many over here used a wheely bin. I use a whisky barrel. sadly it only has water in it.
Gyroscopic action is what causes boats to corkscrew through the water. Does it corkscrewing in the opposite direction down under ? The flywheel is OK but the engine parts arn't.
It's the reason that a front loading spin dryer has a big weight one top . A twin tub can spin much faster and doesn't need the weight.
That's what HID says.

I thought about using the swimming pool but thought the fuel and oil slick may not be appreciated just no pleasing some people.

[Taspiper]

Ok,
Third sea trip today. Seagull got wet and started first pull.
At full throttle it would run for five minutes then back fire and spit out of carby. Stopped fiddled with the mixture and away again. Fiddled with the mixture a few more times but still had a bit of a miss.
Thinking about drilling a hole in the carby cap so I could adjust the mixture on the go.
Caught some fish.
Wind came up and a bit of chop and spray, motor still ran.
About a two mile trip back to the boat ramp and the motor lasted all the way but still misses running around half throttle any more and it would backfire and start to stall. Closing the throttle quickly and reopening would resume power.
Any ideas?

By the time we got back the motor was fairly hot from running 1/3 throttle for half an hour against the tide.
How hot is ok?

When home I thought bugger it and off with the head to check the water ways even though flow through the tell tale is good. When disconnecting the fuel hose a heap of crap came out of the hose so maybe I had been running lean with a bit of a blockage behind the new sintered in line filter (tank gauze gone). Directly under the head all the ways were blocked for some way in. Cleaned and washed all the galleries and reassembled with fresh paint on the block and head. Almost looks like a new pin apart from some polish on the flywheel.......maybe tomorrow.

I'm still concerned about the missing so I may as well invest in a main jet and number three needle. At least that way I'm starting in the ball park.
Ideas?

Cheers Rolf.

[Oyster 49]

Sounds like you are doing all the right things. Keep going!!

[Daryl]

With 2 strokes too lean a mix generaly gives spiting back through the carby.

[Taspiper]

With 2 strokes too lean a mix generaly gives spiting back through the carby.

Yeah thanks Daryl. After seeing the crap that came out of the fuel line and down my leg while I'm sitting behind the motor about to give it a head job, I'm thinking that may of been the problem.
Pour on the power, goes for a while, starts running lean and pop spit starts to stall, reduce throttle, fuel builds back up and away we go again.....