Mercury classic 40hp two stroke

Mc Tool

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My apologies, just realized it posted 1982 and should have read " 1992" ...damn spell checker or what ever it us called often changes characters that I don't catch....don't know how to turn it off...
Just went back to recent posts and found more character changes on them !!
There is spell checker which only underlines spelling mistakes ,and if you hit the underlined word it gives you options , then there is the auto correct which I think is what your refering to . Easiest way to suss it is to google "how to turn off auto correct " , its usually on -settings- general- keyboard and then toggle on or off ....but yeah ,it can drop you in it 😁
 
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racerone

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The hole just allows air / fuel mixture into the by pass area before going into the cylinder.----Direct charge was a " marketing term " to fool folks that direct charge was nearly equal to " loop charging " I believe.
 

jimmbo

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While there was some Licence(have you ever seen a Company that doesn't stretch the Truth about it's Product?) used in Marketing the Direct Charge, it was still an Improvement over the older Cross Charge design.
 

jimmbo

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A hole for one thing allowing for Direct Charging the cylinder.
The Motors that utilized the Hole in the Piston, were called 'Power Ported'. The Block had to be redesigned to accommodate a Trench in the Cylinder Wall for an additional Transfer Passage
While all Power Ported Motors were Direct Charge, not all Direct Charge Motors were Power Ported
img036.jpg
 

Mc Tool

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Hey guys I did change the original post to 1992 because Airshot requested it. After doing so it made several of the other post look like they didn't know what they were talking about. Sorry about that folks, I should not have done the change and will remember that next time
Most peeps will figure it out now 🙂🙂
 

Mc Tool

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The Motors that utilized the Hole in the Piston, were called 'Power Ported'. The Block had to be redesigned to accommodate a Trench in the Cylinder Wall for an additional Transfer Passage
While all Power Ported Motors were Direct Charge, not all Direct Charge Motors were Power Ported
View attachment 417851
2 stroke motorbikes had similar. I guess it is about marketing and each manufacturer thinking up their own name for what is basically the same thing .
I recall one bike manufacturer making a big deal about "crankcase induction" but 2 stroke outboards all do it ....maybe not Seagulls or other piston ported motors ( no reed valves ) and loop charging to me is schnuerle porting ...like normal porting and cross flow is what they had before they twigged to loop charging . With the benefit of hindsight some of the older stuff looks horribly inefficient ....I guess thats progress 🙂.
 

jimmbo

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Yes , i think i will check compression . Obviously i,m hoping for similar results on all cylinders , but what numbers i,m looking for ? +100 psi is ok ?
Merc never used to specify a Number. Instead they would say as long as the Numbers weren't lower than 15% of the Highest you were good to go. Of course if the Highest was low... Gauges can be wonky too. Personally if any were lower than 105 - 110, I would be Leary, but that is just me
Those are pretty good engines, as long as they been fed a good Oil and haven't been overheated
 

Texasmark

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The hole just allows air / fuel mixture into the by pass area before going into the cylinder.----Direct charge was a " marketing term " to fool folks that direct charge was nearly equal to " loop charging " I believe.
Well they had to have something to advertise prior to OMC's patent on Loop Charging, running out (opinion). There was definitely something to it as I had superb fuel efficiency with that engine vs a 1972 Johnson 125 (engine rated, cross flow) I bought new, besides super hole shots and great top ends with the original Mercury Laser ported SS prop on a Ranger with a pad.
 

Mc Tool

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Well they had to have something to advertise prior to OMC's patent on Loop Charging, running out (opinion). There was definitely something to it as I had superb fuel efficiency with that engine vs a 1972 Johnson 125 (engine rated, cross flow) I bought new, besides super hole shots and great top ends with the original Mercury Laser ported SS prop on a Ranger with a pad.
Do you mean OMC had the patent on the term "Loop charging" coz they weren't the only ones using that transfer system ,..I mean maybe not on outboards .🙂
 

Texasmark

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Do you mean OMC had the patent on the term "Loop charging" coz they weren't the only ones using that transfer system ,..I mean maybe not on outboards .🙂
I get decades mixed up since there have been so many in my life but I think it was in the 1968 (?) model year, OMC came out with a 55 HP Evinrude "Triump" 3 cylinder, loop charged engine, with a new streamlined lower unit.....got rid of the protruding LU gearbox. A year or so later (remembering) Johnson came out with theirs.....since both makeup the Outboard Marine Corp. (OMC) the existing patent would cover both companies. That was the first I heard/read about Loop Charging and read up on it. I have no physical documentation attesting to the fact that OMC originated that process or had that process patented....would have been stupid not to.......the process may have been coined elsewhere in previous years, but the application of the process to the marine power industry would surely be patent material. As I recall, patents are (were) for 7 years.
 

racerone

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???-----Lawnboy power mowers ( OMC product ) were loop charged in the mid 1950's.-----And JOHNSON / EVINRUDE both had the 55 HP triple in 1968 as well.
 

jimmbo

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Loop Charging goes back to 1925 when it was first Patented by a German company for use in a 2 Stroke Diesel. Even the small COX 049 model plane Engines were Loop Charged
 

Mc Tool

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Yeah invented by Adolf Schnerle in 1926 ( according to google ....I wasnt actually there😁)
 
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