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Author Topic: SC 61 break in.  (Read 14494 times)

ids987

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Re: SC 61 break in.
« Reply #75 on: February 19, 2007, 02:58:23 PM »

Hi
Just thought I would show you what happened to my brand new engine (SC60) after trying to run it in at home on a water pump.
This motor was brand new, thought I would run it in by circulating the water around the head with a fuel pump to save me time over the lake, the pump was run on 7.2 volts so there was a fair old gush comming out of the side of the boat and back into the water pick up bucket. As you have probably read was having a lot of problems starting it and keeping it going, then I noticed the compression had gone off, when the engine was stripped down I found that the piston had semi sized and destroyed the fit. I believe this was caused by the piston and liner not being able to reach there opperating temperature due the amount of water cooling the engine, this meant that the piston and liner could not expand at the same rate so I guess that the piston expanded more than the liner and seized resulting in the loss of compression. Lucky Piston and liner for the SC only 30. Boat is now running well, with only a trickle of water comming out of the outlet pipe but it runs cool for 10 Min's no problem, so lesson learned there then, looking to get a better carb for it as I think this has a lot to do with the bad idling and poor starting. Oh well nice afternoon, I'm out flying.
Atb
Steve.

Hi Steve / Biscuit,

As the others said, well done for sticking with it.
I think you surmised correctly as regards the overcooling (normally the brass sleeve will expand more than the aluminium piston, so that the fit loosens up somewhat while it is running - to achieve the correct fit when warm and run-in). I believe there is another important factor though - which is related to your running problems. If the engine revs hard when the throttle is closed, it is running in a very lean condition, and hence deprived of oil. If you add this to the fact that it was a new engine - therefore tight, and made worse by the overcooling, it's not surprising the piston and sleeve suffered.
The lean condition in itself will not do any good though, so the carburation does really need to be sorted. I broke a rod on a brand new SC .61 on shore - in the time it took to burn the fuel stored in the crankcase.
The SC carbs can tend to leak air around the main needle - which can usually be helped with a suitably sized length of silicone tube - all the way from the carb body to the outboard end of the needle screw. This will also grip the spring, and help to stop the main needle unscrewing. If it revs when the throttle is closed, with the low speed needle is screwed well out, it almost has to be an air leak or a blockage - unless you are using pipe pressure on the fuel tank. If you use pressure, sometimes you need to go very lean on the main needle to compensate for the pressurised fuel - leaving it short of fuel when you close the throttle. From what I have seen, the SC carb's don't like pipe pressure.
Agreeing with the others again, there are much better carbs out there than the SC, and some good options have already been suggested.

Good Luck and Happy Boating:
Ian
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Biscuit

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Re: SC 61 break in.
« Reply #76 on: February 24, 2007, 01:16:29 AM »

Thanks Ian, Yeah must be an air leak some where, but it runs fine in the water, still waiting for the next outing, wish I had a lake I could go to anytime!! not run my boat for a month now, have heard that they are prone to braking rods. Got dvd of my boat running will try and post a few pixs!!
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martno1fan

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Re: SC 61 break in.
« Reply #77 on: February 24, 2007, 08:27:02 AM »

Thanks Ian, Yeah must be an air leak some where, but it runs fine in the water, still waiting for the next outing, wish I had a lake I could go to anytime!! not run my boat for a month now, have heard that they are prone to braking rods. Got dvd of my boat running will try and post a few pixs!!
post the vid on utube or similar then we can all watch it hehe!!these engines are strong ,better than os in my opinion.
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Biscuit

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Re: SC 61 break in.
« Reply #78 on: April 16, 2007, 11:37:57 PM »

Hi All,
Sad really but boat up for sale, got no where to run it so 350
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martno1fan

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Re: SC 61 break in.
« Reply #79 on: April 17, 2007, 09:49:28 AM »

Hi All,
Sad really but boat up for sale, got no where to run it so 350
what happened? .
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Biscuit

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Re: SC 61 break in.
« Reply #80 on: April 18, 2007, 07:18:44 AM »

Well we lost our lake over to fishing, and Stubbers was just a one off,  my model shop seems to have lost interest, its selling boats but don't seem to keen to hire out any lakes. Could join Brentwood, but thats a fair trek and don't want to join anymore clubs. We did have a guy who ran electric said we could use his lake on race days but we would have to join Electra and only have an 1/2 hour slot. Shame, but  least I had one good day out with it, no one seems to have much enthusiasm any more down here, so need some cash to buy some more lipos for my Helicopter.
ATB
Steve.
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martno1fan

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Re: SC 61 break in.
« Reply #81 on: April 18, 2007, 02:24:14 PM »

sorry to hear that mate so why wont they let you run boats on a fishing lake? do they think your gonna hurt the fish lol?.are there no council run lakes near you at all ?also id check that the club you mentioned actually owns the lake they use cos if they dont they cant stop you using it whenever you want to.
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HS93 (RIP)

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Re: SC 61 break in.
« Reply #82 on: April 18, 2007, 02:31:35 PM »

Say it's a Bait Boat, for fast fish.

sorry about that I know its getting harder to sail these days

Peter
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Biscuit

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Re: SC 61 break in.
« Reply #83 on: April 18, 2007, 09:31:25 PM »


Yeah your right no where now days seems to like I/C even our flying field has had its I/C days cut right down. So remember nice boat up for grabs ! lot o time and money spent, I know its only a SC 61 but goes like a bat out of hell.
Steve.
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glennb2006

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Re: SC 61 break in.
« Reply #84 on: April 19, 2007, 12:48:41 AM »

Well, I would buy it, but I heard the previous owner had trouble with the engine...........

 :D

Glenn
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Biscuit

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Re: SC 61 break in.
« Reply #85 on: April 19, 2007, 07:44:39 AM »

The word is had !! now its got a new piston and liner its fine  :P
Cheers,
Steve.
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Biscuit

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Re: SC 61 break in.
« Reply #86 on: April 20, 2007, 02:08:29 PM »

Ok , Take it no one interrested,   ???
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martno1fan

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Re: SC 61 break in.
« Reply #87 on: April 20, 2007, 04:38:19 PM »

what heppened to the pics of her running?
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Biscuit

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Re: SC 61 break in.
« Reply #88 on: April 20, 2007, 09:18:25 PM »

They were on  my model shops computer, they could not get them on to disc or something like that.  :-\
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Biscuit

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Re: SC 61 break in.
« Reply #89 on: June 23, 2007, 04:34:14 PM »

Can anyone tell me what this spring type clip thing is doing in the barrel of my SC 61 Carb? have not sold the boat (although I wish I had) so took it out today to a new piece of water, but as I was starting the boat, (nightmare) the barrel decide to lock open flat out, this spring thing had slipped down and stopped the barrel from closing. Will take it out and run without it, but why is it there??
any help/
Thanks
Biscuit
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retro boats

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Re: SC 61 break in.
« Reply #90 on: June 23, 2007, 05:19:37 PM »

hi biscuit

i no expert on sc carbs but it looks as if its a choke, i expect the same carb is used on the sc 90 but without the sleeve, if it is removed you will have to re-set the carb as it will suck in more air than fuel, running without it will probably make it not throttle as well


                             steve
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Biscuit

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Re: SC 61 break in.
« Reply #91 on: June 23, 2007, 05:54:10 PM »

Yeah did wonder that, but it is so thin, cant really see this making much difference, my cars have restrictors in the carbs these can be as much as a 2mm wall thickness, this is .5 of a mm, still I am open to all suggestions.
Thanks
Biscuit.
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