Re: Crossflow vs. Looper
 

Does your motor run hot? More compression means more fuel use and higher temps.

Re: Crossflow vs. Looper
 

The 205 psi is in my 1987 CR 250 dirt bike, but it is a looper so I thought I would throw it in here.

Re: Crossflow vs. Looper
 

I thought any two stroke above 145psi couldn't run on pump gas. That was the rule I heard . . . :P

Re: Crossflow vs. Looper
 

I run VP12 114 Octane racing fuel in my jetski with the 230 PSI. I have run it on 93 Octane in her but doesn't like it much, only $5.99 a gallon for that puppy. That bike isn't a looper actually it's the same as my jetski they are called piston port motors. whole different world in 2 strokes.

Re: Crossflow vs. Looper
 

It doesn't now, but the previous owner kept having issues with it(hence how I got it). It's got stock heads and flat top looper pistons, mine was an early one and came stock with the bigger rods. Mine was also before they lowered the compression for unleaded gas. They offer the low compression heads for it, but why change it. It runs great, I've got close to 200 hours on it since I did anything to it internal. And I even run it on 87 octane with no spark knock at load(but does rattle a little at idle on the low octane). It seems to get great economy to boot for a V4. 7-8.5GPH @ cruise and burns around 13GPH WOT.

Re: Crossflow vs. Looper
 

hey that's not bad the highr compression will give it more power arrrr oh yeah more power

Re: Crossflow vs. Looper
 

Yep, it runs pertty good. Like I posted earlier, it pulls off the same top end as a 150 SUZUKI on an identical hull. And there was a guy on the local lake none to happy when his 18' hydro stream with a 150 EVINRUDE XP couldn't catch me. It also didn't help that there was 5 in my boat and he was by himself in his ;D.

But those hydro streams can move, a buddy has an identical hull with an old built up 2.4L MERCURY said to putting out around 280HP. He's GPS'd it @ 98MPH before he ran out of lake with 2 on board. He figures he's had it up around 102 before, but no GPS at that time.

Re: Crossflow vs. Looper
 

This is some great stuff u-all. What is the difference between a big bore and a small bore looper ? Also where do i look on my OMC to find the motor numbers.......ps also how many hp is 2.7 liter ?

Re: Crossflow vs. Looper
 

the small bore has 3.500 pistons which were in all pre 1988 loopers and big bore have 3.685 bore in 1988 up looper 120,130,140,200,225,250,275,300 hp motors


V-4 Models
1.6-liter Crossflow, 1983-1987, and 1988-1990
1.8-liter Looper, 1985-1987
2.0-liter Looper, 1988-1990

V-6 Models
2.5-liter Crossflow, 1983-1990
2.6-liter Crossflow, 1983-1990
2.7-liter Looper, 1985-1987
3.0-liter Looper, 1988-1990

V-8 Models
3.6-liter Looper, 1985-1987
4.0-liter Looper, 1988-1990



the 2.7 was a small bore and has either 200 or 225 HP depends on what carbs you have and jets. do the carb butterfly's have 2 or 3 screws holding them in? 2 will be 200 Hp *carbs and 3 will be 225 Hp carbs.

Re: Crossflow vs. Looper
 

Again w/ the OMC Spec Wallpaper. ;D ... Skools, couldya just be a little more specific ;D ;D ;D ...

Re: Crossflow vs. Looper
 

My 140(same carbs as a 225) only have 2 screws holding the butterflys in, and all of the 225's I've worked on have only had 2 screws holding the butterflys in. These were all 91 and older motors though. I know the throttle plates are different in between the two. They have different size air cuts in them, and are 2 different sizes. Except for 85. In 85 they kept the same carbs for both 120 and 140. The 120 had 57 main jets with 18 BTDC timing, and the 140 used 59 main jets with 22 BTDC timing. But OMC quickly found that this led to cylinder overheating(hence how I came abouts my 85 140).

Re: Crossflow vs. Looper
 

those aren't 140 nor 225 carbs those are 120 and 200 carbs. the 140 and 225 carbs all have 3 screws trust me i have 6 - 225's currently , 5 - 140's, 1 - 200, and 1 - 120

i have 3 extra sets of 200 carbs and 4 sets of 225 carbs. the 120 used smaller reeds and smaller carbs the 130 uses smaller reeds and larger carbs and the 140 uses the large reeds and large carbs.

Re: Crossflow vs. Looper
 

Disreguard most of this statement :-[. I went and re-checked my current 140 carbs and they do have 3 screws in them. But I'm 99.9% certain(can't be 100%, I threw them out when I started my last engine build needed space) that my 85 carbs had 2 screws in them. I know they were not 120 carbs because I compared them to a set of 120's before I got my 87 140 carbs. They had different holes drilled in them than the 120's had, but they did use pretty much the same butterfly size as the 120's.


Let the beatings begin.

Re: Crossflow vs. Looper
 

lol it's ok here's a few of my spares

these are 200 carbs.

http://i8.photobucket.com/albums/a46...s/MVC-049S.jpg

http://i8.photobucket.com/albums/a46...s/MVC-055S.jpg

http://i8.photobucket.com/albums/a46...s/MVC-050S.jpg

these are the 225 carbs

http://i8.photobucket.com/albums/a46...s/MVC-051S.jpg

http://i8.photobucket.com/albums/a46...s/MVC-053S.jpg


notice how much larger the throats are on the 225 carbs they are hugh compared to the 200's

Re: Crossflow vs. Looper
 

My 87 carbs look like your 225's, but my 85 carbs' butterfly's looked NOTHING like either of them. I remember them having smaller throats than my current ones, but they had a big cut on them on the edge of the butterfly and only 1 big holed drilled in them. I had nothing but problems out of the 85 carbs with high idle. I could get it to idle at around 5-600 in gear and it would race up to around 1500 in neutral. I kne they had some vacuum leaks in them as well, but the plastic wasn't warped.

Oh well. Switched out to my 87 carbs, rejetted them and aint had no problems since.