WideOpen Throttle (WOT)

Report the performance of your boat, supply as much information as possible (weight, HP, prop, speed, etc.).
Subject: Make the Glen-L design name the subject. If the design already has a posting, add your information to that post.

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Re: WideOpen Throttle (WOT)

Post by Caber-Feidh » Mon Mar 16, 2009 9:34 am

Lugging a 2-smoker is a bad idea. From an engine life standpoint, I would rather have an engine 500 over MRR than lug it 500 under. With a 2 stroke the combustion chamber temps rocket (red makes it look hotter, eh?) up when it's lugged down. The exhaust looses scavenging efficiency, further raising the temp. The cylinder pressure goes higher as a result of a longer dwell time with the port open, (you guessed it, raising temp) and causing excessive ring-to-cylinder pressure, adding friction heat to the whole debacle. The now hotter piston expands more, and you loose piston/bore clearance, and the ring may become trapped in it's grove. The smaller clearance scrubs lubrication from the bore, the bore glazes, and eventually the piston scuffs the bore. Then you get to rebuild the powerhead. (Can you say parts OBS-NLA?)

Other case: the engine runs hotter as above, combined with longer port-dwell times the effective C/R goes WAY up. the engine goes into a detonation condition as a result. The pinging stresses the cast piston which then cracks and drops a piece of the skirt. Now nothing makes a mess quite like a big hunk of aluminum bouncing about in a case with a crankshaft spinning at 6K. As much fun as case one is... this one is going to be more likely. Well, at least now you won't be tempted to think you are going to rebuild this one! That big hole in the case is a real mood wrecker, especially when it starts raining and all you have is a battery-box cover for a paddle. (don't ask, some things are better not remembered too vividly :? )
Some plan to stroll through Saint Peter's Gates, I plan to go through them at 150mph... backwards... in a screaming ball of flame, with a glimmer belt wrapped around my head, and a NOx button in my hand.

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Re: WideOpen Throttle (WOT)

Post by bob smith » Tue Mar 17, 2009 4:45 am

Battery box covers also make good emergency bailing buckets.
Boating Tip # 564 Check your block drains BEFORE launching this spring.
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Chester, SC

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Post by mobil300 » Tue Mar 24, 2009 7:15 pm

Mr Hot Rod wrote:Al and I are almost neighbors
The Thread Got Bumped So I Have A Second Chance At This Dig...

Paul And Al Are Almost Neighbors Only Because We Keep Quebec Around So That The Maritimes(The Best Part Of Canada) Would Float Out To Sea If They Separated... :lol:

"Roadside Bomb" Is a Very Loose Term For Something That Very Often Appears In The MIDDLE Of Whatever Surface You Happen To Be Travelling On. Note: The Same Phrase Has Also Been Used In Relation To Donkeys Stuffed With C4.

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Re: WideOpen Throttle (WOT)

Post by Dave Grason » Wed Mar 25, 2009 3:15 am

Caber-Feidh wrote: That big hole in the case is a real mood wrecker, especially when it starts raining and all you have is a battery-box cover for a paddle. (don't ask, some things are better not remembered too vividly :? )
Ah, life's school of hard knocks lessons. I've always described that kind of thing to others as "...it's not important how I know that." Even though we may not want to remember too vividly, somehow we always do. :D
Isn't it amazing!! The person that never has the fortitude to pursue his own dreams, will be the first to try and discourage you from pursuing yours.

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Re: WideOpen Throttle (WOT)

Post by 180shabah » Tue Mar 31, 2009 6:58 pm

Don't forget about shifting props.

I have a quicksilver powershift2 that changes pitch by six inches when it shifts, it has a very noticable "hard" shift.

I have also gathered enough serviceable parts to build a torqueshift prop. It requires a little more tuning to dial it in, but it opperates more like a CVT with seamless changes in pitch to match current demand.

I am looking forward to testing the torqueshift this summer.

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Re: WideOpen Throttle (WOT)

Post by Scott » Sat Apr 04, 2009 4:28 pm

Stainless props only work well on larger boats with a big displacement or smaller boats running with a full load or maximum load. Though take this into consideration - some smaller stainless steel props come in various pitches/diameters over aluminum props and have more blades than aluminum props. Where 3 blades are good for speed a 4 blade stainless steel on a small outboard with a larger load introduces better handling at higher speeds, and better thrust than a 3 blade stainless steel or aluminum. Top speed wise isn't so good though.

Also the stainless steel props, 3, 4 or 5 have less blade flex and the durability is much higher than aluminum. But if you hit a rock or log the aluminum still wins because its cheaper to replace or fix.

Remember ask about which type of alloy is used within your prop. Aluminum I believe is standard all around but stainless steels are different, if you get a cheap stainless steel prop it could of been just coated steel, to be sure get a magnet.

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An ignition system of early Mercury outboards that not only is a nightmare to diagnose but also improves a marine mechanics competency.

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