Thanks Thanks:  0
Likes Likes:  0
Page 15 of 19 FirstFirst 12345678910111213141516171819 LastLast
Results 141 to 150 of 190

Thread: Gt Pro -- New Class For Region 8

  1. #141
    Team Member Chairman's Avatar
    Join Date
    Nov 2005
    Location
    Hackensack, MN
    Posts
    221
    Post Thanks / Like

    Default

    Quote Originally Posted by RTM View Post
    What about gear ratios, is there a difference between the 25 and 35? Are all years the same?
    Rich
    As far as I know, the only difference in gear ratios comes with the 1976 35hp. The ratio changed with the 1977 and has been the same since. By 1985 all the 31.8 cube motors, 20, 25, 30 and 35, had thru-hub exhaust, and they all share the exact same lower unit.

    By the way, the 30hp and the 35hp are for all practical purposes the same motor.

    Also many, if not most, of the current GT Pro drivers use a 25hp motor that has been upgraded with nothing but a 30/35 carburetor. That's really all it takes.

    The '94 block does have the extra small 'fingerfile' ports but I have no idea of their effect.
    First I've heard of this, and would like to know more. What are 'fingerfile' ports?

    Tunnelboat and V-bottom Plans for 15-35 hp, 40-60 hp, 60-80 hp

    Dillon-Racing.com also on YouTube, on Facebook, on Twitter

  2. #142
    Team Member Smokin' Joe's Avatar
    Join Date
    Mar 2007
    Location
    Texas and Tirol
    Posts
    657
    Post Thanks / Like

    Default

    Small vertical slit-style extensions of the ports.

  3. #143
    Team Member Smokin' Joe's Avatar
    Join Date
    Mar 2007
    Location
    Texas and Tirol
    Posts
    657
    Post Thanks / Like

    Default

    [QUOTE=Chairman;90102]As far as I know, the only difference in gear ratios comes with the 1976 35hp. The ratio changed with the 1977 and has been the same since.

    What's the 1976 GR? I don't have a service manual for that year.

  4. #144
    Team Member Smokin' Joe's Avatar
    Join Date
    Mar 2007
    Location
    Texas and Tirol
    Posts
    657
    Post Thanks / Like

    Default

    Maybe it's a 1993 block. I have block that was given to me, late model, my dealer friend identified it as early 1990s because of the extra ports. Has not the usual identification on the block, instead has an i.d. nr. that indicates it was a replacement block from OMC in Atlanta.

  5. #145
    Team Member
    Join Date
    Jul 2008
    Posts
    146
    Post Thanks / Like

    Default

    Quote Originally Posted by Smokin' Joe View Post
    Small vertical slit-style extensions of the ports.
    If you are referring to the exhaust ports, those are compression relief slots to make the manual start motors easier to pull.

  6. #146
    Team Member JohnsonM50's Avatar
    Join Date
    Apr 2005
    Location
    Jersey
    Posts
    1,030
    Post Thanks / Like

    Default

    Quote Originally Posted by Popa Sam View Post
    If you are referring to the exhaust ports, those are compression relief slots to make the manual start motors easier to pull.
    I heard that before but wasnt sure if it was that or something else having to do with pre-charging the exhaust to help keep the fuel charge in the compression chamber.

  7. #147
    Team Member Chairman's Avatar
    Join Date
    Nov 2005
    Location
    Hackensack, MN
    Posts
    221
    Post Thanks / Like

    Default GT Pro For Sale

    Listed in the Classified section:

    http://www.boatracingfacts.com/forum...0766#post90766

    Just wanted to let you know my two-time Highpoints Champion Dillon Pro Vee is for sale to anyone who will come and race with us here in Minnesota.

    See the YouTube link at the bottom of this post.

    Racing starts first weekend of June, so don't delay.


    Tunnelboat and V-bottom Plans for 15-35 hp, 40-60 hp, 60-80 hp

    Dillon-Racing.com also on YouTube, on Facebook, on Twitter

  8. #148
    Team Member
    Join Date
    Jan 2005
    Posts
    154
    Post Thanks / Like

    Default

    The small slots in the exhaust ports make the motor idle smoother. The older ones that did not have this had a distinct "hammering" idle quality.
    Outboard Model Concepts
    RC Mod-VP hulls
    Distributor for HTB Tunnels

  9. #149
    Team Member
    Join Date
    Apr 2006
    Location
    Central Florida
    Posts
    109
    Post Thanks / Like

    Default carbs

    What are the differences between the 25hp carb and the 35hp carb? Is it more than just swapping the high speed fixed jets. Are there differences from year to year?

  10. #150
    Team Member Chairman's Avatar
    Join Date
    Nov 2005
    Location
    Hackensack, MN
    Posts
    221
    Post Thanks / Like

    Default

    Main difference is the diameter of the venturi. The carbs shown are 1980s vintage with the idle jet in the front. Later ones had it on the starboard side. 1970s carbs had a choke. Later ones use a primer.


    Tunnelboat and V-bottom Plans for 15-35 hp, 40-60 hp, 60-80 hp

    Dillon-Racing.com also on YouTube, on Facebook, on Twitter

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Who's Who in Boat Racing
    By Mark75H in forum Boat Racing Encyclopedia
    Replies: 395
    Last Post: 09-30-2017, 08:50 PM
  2. A Howard Pipkorn Class???
    By Ron Hill in forum Tunnel Outboards and Tri Hulls
    Replies: 10
    Last Post: 01-12-2007, 10:15 AM
  3. New SE Circleboat Racing class proposal
    By Norseman in forum Mini Boats and Mini Boats History
    Replies: 5
    Last Post: 03-16-2006, 04:55 PM
  4. Entry level class info!!!
    By T-REX in forum BRF Open Discussion
    Replies: 1
    Last Post: 08-20-2005, 03:27 PM
  5. Australian Junior Racing
    By Drats in forum BRF Open Discussion
    Replies: 5
    Last Post: 03-20-2005, 11:53 AM

Tags for this Thread

Bookmarks

Posting Permissions

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