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m4mike
United Kingdom
63 Posts |
 Posted - 03 Jul 2012 : 20:21:58
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Evening everyone, without this sounding like a silly question, is there any limit to the size outboard I could fit to my Norman 23? I have a old Honda 10hp which I find underpowered for the Thames, especially when the river is flowing and a strong wind (the conditions not me!) only I have a chance of getting a marina 40 hp with electric start of a speedboat and was thinking of putting it on my 23, I know I wouldn’t be able to use it to the fullest, but would be good to have some extra power, just wondering about the weight etc., would I need more ballast at the front? I already have 2 bags of bricks.
Thanks.
Mike |
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adi-n-chez
United Kingdom
1980 Posts |
Posted - 03 Jul 2012 : 21:43:46
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Mike
I agree that a 10HP may be a bit underpowered , but if its an old one it may be the same power as a later 15.
Saying that I find our BF15 adequate on the Soar even on high water , & fine even on the tidal trent , although a 20 would be nice when pushing the tide!
If the Marina 40 is a two stroke I wouldnt touch it ! - Fuel Economy will be terrible & it will not like running at low speeds, If its a 4 stroke , then you will still be suffering as you will be running mainly on very low throttle - Presume you are not cruising the Tidal reaches of the Thames ???
Another favourite of mine...... Have you tried removing the building from the front of your boat ? Amazingly the Wheeldons were quite adept at buliding hulls & I have found all of the Norman range I have steered (18/20/22/23) work well without ballast, although the sorter ones are skitty at slow speeds , worth a try (For more than a short cruise as it will take time to adapt to the different handling characteristics of your boat.
Adi
Sewer Tubes ? I'd rather have a D**ncr*ft (Only Kidding) |
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newcommer
United Kingdom
63 Posts |
Posted - 03 Jul 2012 : 21:47:18
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Hi mike
I have a 15 hp Mercury on my 23 and a 4 hp on a bracket. Before we bought the boat it had a 30hp 2 stroke. The 15 has been just enough for the Thames on a yellow rising. We use to say 1hp for foot of boat the main advantage of a bigger engine was charging the batty to run fridge .
Pete
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m4mike
United Kingdom
63 Posts |
Posted - 03 Jul 2012 : 23:54:46
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Thanks for your responses, I use the boat mainly on non tidal Thames, but Teddington lock then into the Tidal Thames is less then an hour away so we do go on there as well, are the two stroke engines that bad on fuel, don't know much about 2 strokes? my old Honda is a manual start, so anoying having to keep taking the rear seat off etc, to start it with all the locks, my main concern is, would the engine be to inpractical and to heavy for the boat.
Cheers
mike |
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df
United Kingdom
5994 Posts |
Posted - 04 Jul 2012 : 07:42:33
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After a 4 stroke you will hate a 2 stroke, also being from a speedboat it may be a shorter shaft length.
Bigger motors don't always charge better as they will be running at a much lower rpm at river speed, most give charge output for when running hard.
NBAS--The communal colostomy bag of the boating community.
Visit leomagill.co.uk |
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m4mike
United Kingdom
63 Posts |
Posted - 04 Jul 2012 : 10:56:22
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Thanks for your reply DF, would a engine this size be just to heavy for the boat? what would the best size be, 20 hp perhaps? all the engines for sale seem to be 2 stroke, I don't know much about them apart from you have to mix 2 stroke oil on a ratio of 50 to 1, do they just use a lot more petrol, are they noiser etc?
Thanks
Mike |
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IanM
United Kingdom
2238 Posts |
Posted - 04 Jul 2012 : 15:00:54
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Noisier, smellier, thirstier and they tend to not like prolonged periods of low revs. You'll be forever cleaning the spark plug and wishing you had a 4 stroke!
But to answer your original question, a 2 stroke 40HP should be fine weight wise but check the inside of your transom for rot first. |
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df
United Kingdom
5994 Posts |
Posted - 04 Jul 2012 : 17:06:06
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Like wot Ian said.
NBAS--The communal colostomy bag of the boating community.
Visit leomagill.co.uk |
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m4mike
United Kingdom
63 Posts |
Posted - 04 Jul 2012 : 18:48:13
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Cheers people, will see what happens when auction runs out on flea bay tonight, speedboat with the engine and trailer and lots of bits and bobs for hopefully £400 can't be that bad? if I don't win the auction, will look for a 20hp 4 stroke with electric start.
Thanks.
Mike |
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m4mike
United Kingdom
63 Posts |
Posted - 04 Jul 2012 : 23:10:33
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Didin't get the speedboat and engine, decided not to in the end, if anyone has or knows of a 20hp 4 stroke electric start engine for sale, can you give me a shout.
Thanks everytone
Mike |
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df
United Kingdom
5994 Posts |
Posted - 05 Jul 2012 : 18:12:55
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quote:
I agree that a 10HP may be a bit underpowered , but if its an old one it may be the same power as a later 15.
I recon you got that the wrong way round Adi, didn't the old motors quote hp from the crankshaft and new ones quote from the propshaft? That would make an old 10hp more like a new 8hp.
15 - 20hp should do you just fine.
NBAS--The communal colostomy bag of the boating community.
Visit leomagill.co.uk |
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IanM
United Kingdom
2238 Posts |
Posted - 06 Jul 2012 : 09:09:58
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quote:
Originally posted by m4mike
Didin't get the speedboat and engine, decided not to in the end, if anyone has or knows of a 20hp 4 stroke electric start engine for sale, can you give me a shout.
Thanks everytone
Mike
You've just alluded to what might be the most economical way to get a suitable engine. It's more hassle but buying another boat complete with engine, swapping the engines over and reselling the boat with old engine is probably the cheapest way, assuming you can afford the time, space and cash. |
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Topic |
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Limit to outboard size on a 23
