Mercury classic 40hp two stroke

[Mc Tool]

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

 

[Texasmark]

What is the difference( if any ) between a crossflow piston and a " direct charge " piston ?

A hole for one thing allowing for Direct Charging the cylinder.

 

[racerone]

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]

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]

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

 

[Mc Tool]

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]

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 .

 

[alldodge]

I messed it up and I changed it back, it should be as it was less my post

 

[jimmbo]

Yes sir. I used to have a picture of Roy Rogers driving his 16' moulded plywood Yellow Jacket with the newly minted 60 HP I6.

This Picture?

 

[jimmbo]

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