User Tag List

Thanks Thanks:  0
Likes Likes:  0
Page 1 of 2 1 2 LastLast
Results 1 to 15 of 27

Thread: motor hop up

  1. #1
    Join Date
    May 2011
    Location
    gaffney,sc
    Posts
    16
    Thanks (Given)
    0
    Thanks (Received)
    0
    Likes (Given)
    0
    Likes (Received)
    0
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    motor hop up

    I know most of you are mercury guys but I have a 86 johnson gt 200 and wanting to make more power out of it. It's the 2.7L, so far I have only drilled exhaust and opened vents and flipped them around on the cowl for more air, I have it down now putting new stator on and fiber reeds. While I'm at it I want to work reed cages and shave heads but know how much I need to cut and what a safe compression ratio is on 93 octane, right now my comp. is 100 lbs on all cylinders. If any one knows any other hop ups or tricks with exhaust tuner, intake manifold, or carbs just let me know, I already know I'll have to fatten up on the jets. Any help at all will be great, just dont say get 280 merc. I've had the motor for a long time on my old procraft and love it, just want a little extra. It's on a light hull, 600lb 17ft xst. thanks
    <!-- / message --><!-- controls -->

  2. #2
    Join Date
    May 2009
    Location
    catskill ny
    Posts
    3,631
    Thanks (Given)
    5
    Thanks (Received)
    1
    Likes (Given)
    31
    Likes (Received)
    26
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    i am sure the omc boys will see this thread and chime in. Compression would be a great start.
    1990 hydrostream virage diamondpower280

  3. #3
    Join Date
    Oct 2010
    Location
    Greenwood Lake, NY
    Posts
    1,835
    Thanks (Given)
    27
    Thanks (Received)
    3
    Likes (Given)
    142
    Likes (Received)
    45
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I know that on the later motors like my 3.0 200hp you can put a set of bigger carbs on from a 225. From what I was reading here the 200 and 225 were the same just different carbs.
    I was going so slow I almost crashed. - JamesGang

    1978 24 Superboat - 250 EFI
    Sold: 1991 Starliner - 250 EFI Merc 3.0

  4. #4
    Join Date
    Jul 2009
    Location
    spokane
    Posts
    787
    Thanks (Given)
    3
    Thanks (Received)
    3
    Likes (Given)
    5
    Likes (Received)
    4
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I would start with what you do have before shaving the heads list which heads they are post it on here also which carbs are on it number on one of the sideplates on one of the top carbs and post that also this motor could have some of the best omc had to offer

  5. #5
    Join Date
    Sep 2009
    Location
    iowa
    Posts
    661
    Thanks (Given)
    1
    Thanks (Received)
    2
    Likes (Given)
    0
    Likes (Received)
    3
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I thought the '86 200's were 2.6 and the 87 200's were the 2.7. The 86 and 87 225's were both 2.7. I know these motors were pretty good from the factory. My 87 has a factory gutted airbox. I'm curious to see the difference you get with the new reeds. Its on my to-do list.
    1975 Hydrostream Ventura II
    1987 evinrude 200xp

  6. #6
    Join Date
    May 2011
    Location
    gaffney,sc
    Posts
    16
    Thanks (Given)
    0
    Thanks (Received)
    0
    Likes (Given)
    0
    Likes (Received)
    0
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    My heads are the original 86 200 2.7 heads, the good ones, and carbs are the big bore ones. 85 was the last year for the 2.6 200s, mymotor looks like a 3.0l from 88 up but its the 2.7 like your 86 but with larger bore carbs, when i say i want more power dont think the motor is a slug, on the allison its a beast now, just want more. thanks guys for fast reply, anymore info will be great

  7. #7
    Join Date
    Jul 2009
    Location
    spokane
    Posts
    787
    Thanks (Given)
    3
    Thanks (Received)
    3
    Likes (Given)
    5
    Likes (Received)
    4
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    if you want to swap heads i have a set already milled .59 chamber depth do not mill those heads too many have already been molested dont do it! have someone like racer do some finger porting for you if you want to wake that thing up your compression is low there is nothing wrong with those heads!

  8. #8
    Join Date
    Aug 2007
    Location
    DE WITT AR
    Posts
    265
    Thanks (Given)
    2
    Thanks (Received)
    2
    Likes (Given)
    1
    Likes (Received)
    3
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    you need 140+ lbs of compression, a good set of reeds, you need to jet it safe but not fat. Be sure that timing is right on all cylinders and that you do not have any fuel restrictions and run good non ethanol premium fuel. make sure that your setup is good. setback, prop, engine height. then, if you want more hp, get out your wallet and send the block to monty or racer and get them to port block, pistons, work on intakes, etc. your budget is your limit. good luck, have fun and be safe.

  9. #9
    Join Date
    May 2011
    Location
    gaffney,sc
    Posts
    16
    Thanks (Given)
    0
    Thanks (Received)
    0
    Likes (Given)
    0
    Likes (Received)
    0
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    thanks, that was the answer I was looking for, do you think I can get that much compression with just shaving heads. I know I'm asking alot of questions but I'm new building 2 strokes.

  10. #10
    Join Date
    Jan 2012
    Location
    southold
    Posts
    1
    Thanks (Given)
    0
    Thanks (Received)
    0
    Likes (Given)
    0
    Likes (Received)
    0
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    i talked to my teacher if this is the same motor he is taqlking about you should be also able to switch out the carb and exhaust tuner for one on a 225 and advance the timing it should them have a little more pep if you them tune the carb.

  11. #11
    Join Date
    Oct 2001
    Location
    Mound, LA
    Posts
    15,593
    Thanks (Given)
    2
    Thanks (Received)
    11
    Likes (Given)
    127
    Likes (Received)
    142
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by NosBoss View Post
    I thought the '86 200's were 2.6 and the 87 200's were the 2.7. The 86 and 87 225's were both 2.7. I know these motors were pretty good from the factory. My 87 has a factory gutted airbox. I'm curious to see the difference you get with the new reeds. Its on my to-do list.
    Nope. The 86 2.6L were 175 crossflows. The 200-225 were 2.7 loopers. Check this out. Good for reference. I compare a lot of years to see what part numbers coincide and what ones differ.

    http://epc.brp.com/SiteMods/BRP_Publ...3-2ce481430299

    I hear the later mid bore carbs are the best all around. At least that is what I've been told. I just bought a couple (motors with them) so I'll soon find out.
    Paul Harrop

  12. #12
    Join Date
    May 2002
    Location
    Victorville ca.
    Posts
    375
    Thanks (Given)
    0
    Thanks (Received)
    13
    Likes (Given)
    0
    Likes (Received)
    33
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Take it to Al Stoker get some port work and you will be way happy. If you have the money bore it to a 3 liter and you will have an awesome motor.

  13. #13
    Join Date
    Sep 2009
    Location
    iowa
    Posts
    661
    Thanks (Given)
    1
    Thanks (Received)
    2
    Likes (Given)
    0
    Likes (Received)
    3
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Forkin' Crazy View Post
    Nope. The 86 2.6L were 175 crossflows. The 200-225 were 2.7 loopers. Check this out. Good for reference. I compare a lot of years to see what part numbers coincide and what ones differ.

    http://epc.brp.com/SiteMods/BRP_Publ...3-2ce481430299


    I hear the later mid bore carbs are the best all around. At least that is what I've been told. I just bought a couple (motors with them) so I'll soon find out.
    This is an old thread brought back to life. I've been doing lots of research lately to figure out what I have. My '87 has mid bore carbs on it, but they are the ones correct to the year of the motor. The only issue I have with them is the warped carb bowls that leak. Another issue that I need to solve this winter. Lol
    1975 Hydrostream Ventura II
    1987 evinrude 200xp

  14. #14
    Join Date
    Sep 2006
    Location
    Key Largo, Fl
    Posts
    2,831
    Thanks (Given)
    4
    Thanks (Received)
    75
    Likes (Given)
    14
    Likes (Received)
    167
    Mentioned
    0 Post(s)
    Tagged
    1 Thread(s)
    SThe compression is low for your motor,should be 125 give or take a few.It can be confusing,as 100 lbs is normal/good for a first generation big bore,88-92.Sounds like you need a rebuild,now should be the time for internal mods..ports,cleanups etc.Milling the heads on a well worn motor will just finish it off,Chris
    Last edited by Chris Carson's Marine; 01-15-2012 at 08:05 AM.

  15. #15
    Join Date
    Sep 2009
    Location
    iowa
    Posts
    661
    Thanks (Given)
    1
    Thanks (Received)
    2
    Likes (Given)
    0
    Likes (Received)
    3
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    When I got my motor, it had been in storage for many years and it only had 85-90 lbs of compression. After running it all summer the compression came up to 100 accross all six. I checked it with another gauge just to make sure and got the same results. I never did a leakdown test and know I should have. I recently pulled my heads to have a look inside and found out my motor had been gone through at one point in time. All cylinders are now .030 over according to the markings on top of the pistons. The cross-hatching in the cylinders looks pretty good and I didn't see any gouges. I suppose it might be a good time to teardown and give it a hone and ring. I really don't see that happening this winter as I already have a lot of coals in the fire. I want to pull the front half and see what it has for reeds.
    1975 Hydrostream Ventura II
    1987 evinrude 200xp

Page 1 of 2 1 2 LastLast

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Spinelli Props