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Old 02-09-2013, 09:22 PM   #1
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Weight of a 200/225/250 merc optimax flywheel

My lightened and balanced flywheel has just arrived and weighs 6.6kg.

Anyone know what a standard 200/225/250 optimax flywheel weighs?

Thanks Dave
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Old 02-09-2013, 11:04 PM   #2
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Optimax flywheel weight

for 300 XS
283-859619T04 FLYWHEEL = 20.09 Lbs

For 250XS
283-859619T1 FLYWHEEL = 16.45 Lbs

CNC lightweight flywheel from Simon's & Dave Bush made in aluminum alloy are only 6lbs ...
http://www.davebushracing.com/optima...rformance.html
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Old 02-09-2013, 11:34 PM   #3
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Do these (light) flywheels actually make a difference? Its not like on a car where you can go from idle to max rpm within a couple of seconds or less...
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Old 03-09-2013, 06:52 AM   #4
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weight effects on outboard flywheel

Here a good discussion on the subject, especialy from Jay racing.
http://www.screamandfly.com/showthre...ht+flywheel+XS
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Old 03-09-2013, 08:27 AM   #5
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Exactly as I thought. Thanks
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Old 03-09-2013, 02:50 PM   #6
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Hi Beyondhelp, I use to race Thundercats and removing the ring gear on a tohatsu 50hp made a big difference on acceleration times. You could here the difference on the muffs, the engine use to rev quickly like a motorbike.

You also gain a few extra revs at top end, which on very close racing, made the difference between a win or a loss.
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Old 03-09-2013, 02:57 PM   #7
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For me the difference is simple I have a prop I like but it only revs to 5300 the engine revs to 6000.

The most a depitched will give me is about another 250 revs. Which brings me to 5550 revs, a new prop is £300-400 the flywheel was £120 delivered to the door and should give me another 250 revs.

So basically cheaper and I go slightly faster for my money.

Some people might say why bother, but the revs drop the more people are on the boat and your putting more strain on the motor running over pitched.
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Old 03-09-2013, 04:38 PM   #8
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Quote:
Originally Posted by Banana Shark Dave View Post
and I go slightly faster for my money.

Can't see that myself. I'm sure the motor will be slightly more responsive, but why would it be quicker?
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Old 03-09-2013, 05:19 PM   #9
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I agree... I gained 400 revs easy with some prop work without losing any pitch
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Old 03-09-2013, 05:41 PM   #10
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Light flywheel makes no difference to top end, it'll just accelerate quicker.

If your not making the revs, just buy a new prop, or have it worked, or move the engine up a bolt hole!
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Old 03-09-2013, 07:51 PM   #11
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I beg to differ with our tohatsu 50hp engines they rev faster, and you gain a few hundred revs, granted not much but you do get some.

Going up a hole is out, cavitates to much.
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Old 03-09-2013, 08:02 PM   #12
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Out of interest, what prop? And what speeds do you see?
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Old 03-09-2013, 08:22 PM   #13
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Quote:
Originally Posted by Banana Shark Dave View Post
I beg to differ with our tohatsu 50hp engines they rev faster, and you gain a few hundred revs, granted not much but you do get some.

Going up a hole is out, cavitates to much.
If we're talking about a 3.0L merc then I did it on sunday. Not the slightest difference in top speed.
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Old 04-09-2013, 12:10 PM   #14
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Going out to test tonight, will put the results up later.
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Old 04-09-2013, 08:33 PM   #15
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Couldn't do a proper test as had the wife and 2x 7yr olds and 1x 5 yr old. Turned the same revs in a shorter space as previously with 2x adults. Some slight improvement.
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