Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Pleasure boats, Sports, Race, Power and Leisure Boats: => Topic started by: vintagent on May 16, 2010, 04:57:04 pm
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Hi, my son has got hold of a McCulloch strimmer and we've stripped all the strimmer stuff off it. Now we need to know what kind of hull would suit it and what needs to be done to the motor to get it suitable for model boating.
It has a biggish fan affair integral with the magnets that trigger the "magneto". Can that all be replaced by some transistoriised trickery to cut down on bulk and weight?
This will only be a fun boat, so no advice on tuned pipes, etc. please or you'll bankrupt him!
Also some ideas on drive systems, couplings, etc. The pull start is part of the ugly yellow plastic strimmer moulding. Any ways that can be included but tidied up?
Thanks , we are not experienced in this stuff at all, but fancy an alternative to the ever more expensive electrics.
Regards,
Vintagent
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Hi Vintagent you might find my topic helpful, 28CC WEEDWACKER CONVERTED TO WATER COOLED MARINE ENGINE,
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Hi Patternmaker,
could you give me a link to that thread, please? I tried a search, but it gave me nothing.
Sounds just like what I need.
Regards,
Vintagent
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Hi Vintagent, this link should find it.
Regards Mick
Model Boat Mayhem - Forum
Research and Design Office
Sports Boats R&D:
28cc WEEDWACKER MODIFIED TO WATERCOOLED MARINE ENGINE
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http://www.modelboatmayhem.co.uk/forum/index.php?topic=15773.0 (http://www.modelboatmayhem.co.uk/forum/index.php?topic=15773.0)
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Thanks gents,
our engine is a McCullouch and has its pull start on the front, all part of the yellow plastic casing. The only thing on the back is a plastic crankcase cover (!!)
Finding somewhere to put engine mounts isn't going to be easy without some serious metalbashing.
It has twin ports, or rather a desiamesed oval exhaust port. The carb is a Walbro.
Obviously these things don't HAVE to have a tuned pipe, do they?
It's only a fun boat.
Is it possible to shorten the flexible drive shaft to use in a boat?
And what size prop should we be looking at for a four foot (ish) fun boat?
Regards,
Vintagent
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Thanks gents,
our engine is a McCullouch and has its pull start on the front, all part of the yellow plastic casing. The only thing on the back is a plastic crankcase cover (!!)
Finding somewhere to put engine mounts isn't going to be easy without some serious metalbashing.
It has twin ports, or rather a desiamesed oval exhaust port. The carb is a Walbro.
Obviously these things don't HAVE to have a tuned pipe, do they?
It's only a fun boat.
Is it possible to shorten the flexible drive shaft to use in a boat?
And what size prop should we be looking at for a four foot (ish) fun boat?
Regards,
Vintagent
Hello.
The pipe dose not have to be a tuned pipe However the overall noise should be kep't as low as possible otherwise you will find people getting up set etc etc etc.
Having the pull start on the front end is not good news. However I'm sure you can short it out. The engine will need mounting on rubber mounts otherwise it will shake it self out of the boat in no time. I have tried strimmer flex but they do not last very long 5 mins max. I can point you in the right direction to get the right stuff if you need help.
Any photos of the boat and engine ???
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Hi Bill, thanks for the help.
I can get the lad to take some pics and get them on here.
He got it for nothing and it appears to be fine, so probably just needed some decent fuel!
I'll see if he can get some pics to me.
Regards,
Vintagent
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Leave the fan alone leave the shroud on and leave it air cooled and run it in an open top boat.Heres one of my vees i did for a fellow member using a 28 cc strimmer engine.You can leave the stock can muffler on if you want or modify an exhaust to fit.
Mart
here she is running an oversized prop on her test run.
http://www.youtube.com/user/martno1fan#p/u/3/Xz0VD7b9FBk
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Thanks, Mart.
I'll pass that on to him. Perhaps we can use the plastic shroud and keep the pull start.
Have you mounted the flexibles onto the plastic there? because that's another problem area...trying to find somewhere to put on decent engine mounts.
Like I said, he only wants something to run for fun. No competition. He's actually putting it into a twice sized Veron police launch!
Regards,
Vintagent
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The rear mount is cut so it fits under the pullstart and the screws go thorugh it trapping it between pullstart and engine and the front one is bolted to the front part of the plastic clutch cover.I removed the clutch on that one and cut the cover a little,but you can use the clutch and then use a square end flex but then you have to silver solder a ferrule onto the flex and the ferrule then fixes to a stainless steel stub shaft as in the pic.I made the mounts from ali plate and angle bar.If its a police launch he will be using a submerged prop setup ? so might have to rethink things a bit.
Mart