Increasing hp on a featherweight?

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Merry
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Increasing hp on a featherweight?

Post by Merry »

Any good ways to do this?
A friend of mine has a forty plus which I might be able to get, it has a few problems but I think on the whole its ok? Are any parts interchangeable with mine to give mine more power?
Or are there any other ways to up my speed? Props... Gear boxes.... Changing the engine???
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Collector Inspector
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Re: Increasing hp on a featherweight?

Post by Collector Inspector »

No

Nicely tuned and on correct floater is about it.

Feathers PUSH things very well but fast is and was never an option aye.

B
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Merry
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Re: Increasing hp on a featherweight?

Post by Merry »

Even with an engine change for a bigger cc?
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Re: Increasing hp on a featherweight?

Post by Collector Inspector »

Increasing CC say a 102 power head will increase the horse power yes.

The increase in horse power is somewhat loosely rated at the crankshaft (R.A.C.)

There will be no increase in thrust which is what pushes you through the water. There is a basic limitation as to prop size that fits and the gearbox ratio to consider going this way around. Same revs from the power head remember.

Putting a 102 on the leg will require some messing with the exhaust tube as well. Transom bracket needs upgrading somehow as well as the 40 series brackets are the size they are for good reason.

Consider starting with a complete 102 motor and go from there if performance is your desire. Many options. Research thru the posts aye.

B
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Merry
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Re: Increasing hp on a featherweight?

Post by Merry »

Well all I want from my featherweight is the short shaft, and the recoil start.
I should be picking up another seagull but I'm not sure which It is yet, just know it's a long shaft. Just wondering really what kind of hybrid I could come up with for a bit more speed.
Should also be able to get some bits from a 40+ as a friend has got one with a cracked block.
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Re: Increasing hp on a featherweight?

Post by headdownarseup »

Another option would be to build your own custom made motor to your requirements using readily available parts.

Limitations abound with ALL seagull motors, but with some carefull planning you can get something together that will work.

2 main fundemental differences with a 40 motor and a 102 motor.(far too many to discuss on here, Charles or H-A will talk you through some of them)

Here's what i suggest.
Start with a 102cc powerhead as this will give you a tiny bit more hp to start with. (dont forget that the suggested hp ratings were "optomistic" to say the least)
If you were to retain the short shaft and the recoil ignition from your featherweight (you dont say whether it's a cdi or points type ignition) you can then start to build a super short shaft 102cc variant with suitable lower unit and prop, with all the rest of the correct bracketry for a century powered motor.

Also try and remember that with any seagull they are more like a tractor not a sports car! (except perhaps the very late models with roller bearings in the crankshaft which apparently were a bit more accurate in the hp ratings at around 6-8 hp, but Charles really is the person to speak to on this)

Another point worth mentioning is what type of hull this creation will be trying to push. Both weight and length of hull will be a limitation in this factor.

Before you start building anything, have a word with Charles or H-A to see what sort of things can be done with a bog standard power unit.
Then speak to A-J as he's the guy for anything prop related.
Then have a word with a seagull racer for any more tips and hints.

There is much more to this than meets the eye.

Bottom line is seagulls are not fast or powerfull in standard form. Not that much different when modified either. It's more to do with the boat rather than the engine itself.

Alternatively, look at a short shaft suzuki or mariner or something else if speed is the only thing that's important to you. You'll be hard pushed to get anything like that sort of speed or power from a seagull...

Let us know what you decide to do. (i'm interested in what will be created here. perhaps a frankenmotor :shock: )

Jon
Merry
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Re: Increasing hp on a featherweight?

Post by Merry »

Well I'm picking up another seagull today but all I know so far its a long shaft... And its in bits. So I'll let you know later.
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Re: Increasing hp on a featherweight?

Post by Merry »

Oh and the boat is a little inflatible, about 7ft
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Rob Ripley
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Re: Increasing hp on a featherweight?

Post by Rob Ripley »

Here's an idea - 102 on a 40+ drive shaft and gearbox, hand made tapered exhaust, running a C100 5 blade prop.[attachment=0]DSCF8784.JPG[/attachment][attachment=0]DSCF8784.JPG[/attachment]
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Re: Increasing hp on a featherweight?

Post by headdownarseup »

Some of you might know i have a VERY BIG soft spot for anything roundblock 102.

But this takes things to a whole new level.
I remember seeing this somewhere before on the forum and thought that's a bit special...

That exhaust tube must have taken some doing Rob?
Stainless or plated brass or aluminium?
Does it still have the proper 102 fuel tank?
With the exterior water pipe that's normally fitted down the exhaust tube, is there any water flowing inside the exhaust tube as per a conventional 102? (cant quite make it out in the pics)

How good does it run, and what size boat have you used this on before.

I like that a LOT :P


Well there you go Merry, that's a couple of ideas for you to work on.
Century or 102 powerhead (both the same cc) but fitted to a smaller gearbox/prop combination. This might be the way forward in your quest for more speed!
Inflateable dinghy might have it's limitations though.
If it were me, i'd be looking for a small rigid pram type dinghy rather than an inflateable. (just my thoughts)

Jon
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Re: Increasing hp on a featherweight?

Post by Merry »

Wow I also like that alot!
I'm hoping the one I pic up will be a century, because I'm sure after searching I read that a century gear box with a prop from a forty plus will work well on my featherweight. But if I combine that with the bigger cc of the century too I could be on too a winner!

Will my recoil starter fit on top of a century flywheel?
Merry
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Re: Increasing hp on a featherweight?

Post by Merry »

Ok so I've picked up an old 40 series, as I said it's in pieces and I think I will benefit from the gear box issues I'm having as discussed in another post.
But engine wise for the time being I'm not going to gain anything with it really. But hey its spares to build up a collection to annoy the wife
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Rob Ripley
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Re: Increasing hp on a featherweight?

Post by Rob Ripley »

It's a complete 102 power unit that bolts onto the 40+ drive shaft with the slightly rebent 40+ water pipe. The exhaust is made up from narrow strips of welded copper, moulded into shape with a chromed finish. I did not make it.
I first saw it in 2003 and in fortunitate circumstances came into possession in 2005.
The original power unit was AC806 that has since been reunited with a similar year bottom end.
I've swapped several props and found that the 5 blade seems to give the best power to boat weight, don't see any extra speed.
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Re: Increasing hp on a featherweight?

Post by headdownarseup »

Rob

I understand the basic mechanicals of the 102 block, but i was more interested in the water return pipe that sits on the top of the 102 block at the moment. Where is this pipe fitted and where does it end up? Is it the same as any conventional 102 pipe in that it's fitted to the outside of the exhaust tube. Some of this water then feeds inside the exhaust tube and what doesn't go inside gets pushed out of the bottom of the pipe fixing as a tell tale.

I can't quite make it out in the pics!
Curious that's all (but it does give me a rather nifty idea)

Jon
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Rob Ripley
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Re: Increasing hp on a featherweight?

Post by Rob Ripley »

Jon said ...
.... but i was more interested in the water return pipe that sits on the top of the 102 block at the moment. Where is this pipe fitted and where does it end up? Is it the same as any conventional 102 pipe in that it's fitted to the outside of the exhaust tube ...

Yes, it's the same. The power unit is complete with its water return pipe - so some water is the tell tale, the rest goes into the exhaust pipe - same as any 102.
The water supply pipe is off a 40+, but re-bent to suit the different exhaust shape.
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