User Tag List

Results 1 to 8 of 8
  1. #1
    Join Date
    Apr 2013
    Location
    Lexington, ky
    Posts
    870
    Thanks (Given)
    228
    Thanks (Received)
    15
    Likes (Given)
    1939
    Likes (Received)
    82
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    re-jetting carbs

    When you carb gurus have to increase the jetting on your carbs where do you start, up 2-sizes? Up 4 sizes? I got my new engine (99 2.5 200) together and broken in with some WH-22's and I want to put the WMV-18's back on. They seem to have had better throttle response, idled smoother and got better MPG than the WH-22's. When I got the WH-22's I was told by James Perry what jetting he has had the best success with and everything seemed fine. Another well known builder on here suggested I try some WMV-18's as they were a newer carb with better technology and he had experienced much better success performance wise as well as fuel mileage.

    My new engine is .015 over and on the tight side of tolerance as I don't spin the RPM you hardcore guys do and I need it to last (at least until I get that XB2002 my heart desires), steel cage bearings, rod slots were done, exhaust chest opened up, exhaust ports touched up and heavy chamfered, 1" Chris Carson spacer and reeds, short bell-mouth tuner, 33cc heads (have a set of 28cc for just in case ) and I have opened up my cowling in the front to allow more air in.

    So, suggestions as to how much I should increase these jets to start with? I have EGT probes and a gauge in the dash so I can TRY to not melt this thing down.


    Slimm
    Last edited by Slimm; 10-21-2016 at 03:11 PM. Reason: spelling
    Hire the handicapped, we're fun to watch

  2. #2
    Join Date
    May 2014
    Location
    Livingston, Louisiana
    Posts
    1,349
    Thanks (Given)
    41
    Thanks (Received)
    108
    Likes (Given)
    271
    Likes (Received)
    326
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I usually go up 4 sizes which Is .008 larger than stock then adjust from there. Every motor/boat/set up combination is different.

  3. #3
    Join Date
    May 2014
    Location
    Livingston, Louisiana
    Posts
    1,349
    Thanks (Given)
    41
    Thanks (Received)
    108
    Likes (Given)
    271
    Likes (Received)
    326
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    With the motor being tight I recommend running a little on rich side to help keep piston cool. It'll live a lot longer and you'll have that cushion if something goes wrong or get bad fuel and such.

  4. Likes Slimm liked this post
  5. #4
    Join Date
    Apr 2013
    Location
    Lexington, ky
    Posts
    870
    Thanks (Given)
    228
    Thanks (Received)
    15
    Likes (Given)
    1939
    Likes (Received)
    82
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Sorry I forgot to mention that I have about 15 1/2 hours on it since rebuild. I for sure want to keep it on the fat side. Thanks for the input, that gives me a place to start.


    Slimm
    Hire the handicapped, we're fun to watch

  6. #5
    Join Date
    May 2014
    Location
    Livingston, Louisiana
    Posts
    1,349
    Thanks (Given)
    41
    Thanks (Received)
    108
    Likes (Given)
    271
    Likes (Received)
    326
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Your welcome. First time out I always like to take it easy and shut engine at cruising speed and inspect plugs/pistons to make sure definantly have enough fuel then slowly work your way up. That is if boat will allow you to that without much backwash.

  7. #6
    Join Date
    Aug 2009
    Location
    savannah,ga
    Posts
    672
    Thanks (Given)
    0
    Thanks (Received)
    3
    Likes (Given)
    8
    Likes (Received)
    18
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    WMV's ran the best on mine....the WH series carb did not impress me one bit.

  8. #7
    Join Date
    May 2002
    Location
    Victorville ca.
    Posts
    405
    Thanks (Given)
    0
    Thanks (Received)
    16
    Likes (Given)
    0
    Likes (Received)
    45
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    It is way easier to and cheaper to change jets than pistons!

  9. Likes Slimm liked this post
  10. #8
    Join Date
    Sep 2002
    Location
    Dunlap,TN.
    Posts
    3,135
    Thanks (Given)
    0
    Thanks (Received)
    46
    Likes (Given)
    6
    Likes (Received)
    149
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I use the WH series a lot because they are plentiful and because they don't have the progressive jets they run lean (not enough to hurt the engine) in the mid range and get better economy which is a good point for most people but can be made to run very well if you jet them correctly. I gave you a base to start with as each engine is different due to difference in load, baro, ect. Just my .02
    James Perry

Similar Threads

  1. Wmv carbs & jetting
    By bobthebuilder in forum Technical Discussion
    Replies: 26
    Last Post: 08-04-2016, 04:06 PM
  2. Mercury Tech: 94 xr6 with wmh-32 carbs jetting
    By 200valeroyt in forum Technical Discussion
    Replies: 4
    Last Post: 10-12-2010, 09:20 AM
  3. Jetting Carbs
    By blazer01 in forum Technical Discussion
    Replies: 6
    Last Post: 04-21-2010, 07:48 PM
  4. OMC Tech: re-jetting carbs
    By Archie in forum Technical Discussion
    Replies: 9
    Last Post: 06-17-2009, 11:20 AM
  5. Need jetting help 2.0 135 with wh-28 carbs
    By ssv1761982 in forum Technical Discussion
    Replies: 2
    Last Post: 04-16-2006, 09:37 PM

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
  •  
Diamond Marine