Results 1 to 18 of 18
  1. #1
    Member
    Join Date
    Aug 2017
    Location
    Richmond, Virginia
    Posts
    51

    Question 1988 Johnson GT150 carb roller verification and tuning?

    I just need some clarification please. Johnson GT150, (Model# J150STLACA, Ser# R7831450)... Does this have the clear plastic tubing over the carb roller or not? I thought I saw where that wasn't introduced until 1989. Mine currently does not have it, so I just wanted to verify.

    The motor starts perfectly, idles great, and runs great, however, can only seem to get @4800 WOT, (1996 Skeeter ZX180, 14-1/2 X 24 Raker). It also seems to stumble and bog down a little at times on the hole shot. I'm fairly certain I need new plugs (will look at plugs Thursday). I was also told to run it a little rich on oil based on age of the motor, is why i'm thinking plugs. Is that necessary? Should I perform a sync and link also to be sure?

    A little green to outboards, but certain I can tackle most anything with a little guidance. Any recommendations?
    2000 Ranger R93VS
    2003 Mercury Optimax

  2. Ohio Fishing Reports Moderator omcforever's Avatar
    Join Date
    Nov 2007
    Location
    Miamisburg Ohio/Formerly Aiken SC
    Posts
    20,052
    #2
    gotta have roller and the o-ring retainer.
    0308776 retainer
    0330130 roller
    Last edited by omcforever; 10-31-2017 at 03:19 PM.

    Age and treachery will always overcome youth and skill !!

  3. Ohio Fishing Reports Moderator omcforever's Avatar
    Join Date
    Nov 2007
    Location
    Miamisburg Ohio/Formerly Aiken SC
    Posts
    20,052
    #3


    Same as yours,,,,,,,

    Age and treachery will always overcome youth and skill !!

  4. Member
    Join Date
    Aug 2009
    Location
    Wichita KS
    Posts
    4,917
    #4
    You need to check your model number. Yes the roller sleeve was started in 1989, a few early 1989's don't have the sleeve. 4800 might be all you can get with a 24 Raker, I ran Cajun's and Skeeter's when I fished tournaments, on the Skeeter Starfire 150's and 175's, I couldn't turn a 24 Raker much more than that, so I couldn't run them. I would prop out to run 5600 to 5800 on top end. If you premix oil I wouldn't worry to much about any extra. Spark plugs, Champion QL77JC4 gap at .030. A proper sync and link never hurts. If you don't have one get a real OMC service manual for your motor. OMCforever might have one for you.

  5. Ohio Fishing Reports Moderator omcforever's Avatar
    Join Date
    Nov 2007
    Location
    Miamisburg Ohio/Formerly Aiken SC
    Posts
    20,052
    #5
    I stand corrected, all you need is the roller and o-ring,,,no sleeve
    Last edited by omcforever; 10-31-2017 at 03:18 PM.

    Age and treachery will always overcome youth and skill !!

  6. Ohio Fishing Reports Moderator omcforever's Avatar
    Join Date
    Nov 2007
    Location
    Miamisburg Ohio/Formerly Aiken SC
    Posts
    20,052
    #6
    Sent you a PM,,,,

    Age and treachery will always overcome youth and skill !!

  7. Member
    Join Date
    Aug 2017
    Location
    Richmond, Virginia
    Posts
    51
    #7
    Thanks guys! Looks like I need to replace the roller regardless, it is worn with a slight flat spot. I'll start with prop choice, and changing the plugs. I just feel like they need it, and it's rather inexpensive to do so. Depending on how that goes, I'll do a sync and link.

    Any recommendations on prop?
    2000 Ranger R93VS
    2003 Mercury Optimax

  8. SC Club Moderator ChampioNman's Avatar
    Join Date
    May 2004
    Location
    Crawfordville, FL/Lake Hartwell, SC
    Posts
    71,246
    #8
    I must live in a different world. I had no problem at all spinning a 24P Raker on my GT150 to 5400 on a 20' Champion. You may want to perform a sync n link on your carbs and make sure the plates are opening fully.

  9. Member
    Join Date
    Aug 2009
    Location
    Wichita KS
    Posts
    4,917
    #9
    Take a peek at your roller, in some cases it can be turned end for end and the flat spot won't touch the throttle cam. Which ever you do, just oil the roller shaft, lightly moly lube the cam and roller, the roller not rolling causes the flat spot. I've been out of propping to long, I can't recommend any of the newer props. On my XP150's I ran a 3 blade 22 pitch. I did have a 3 blade 24 pitch Turbo II, that ran good.

  10. Member
    Join Date
    Aug 2009
    Location
    Wichita KS
    Posts
    4,917
    #10
    Quote Originally Posted by ChampioNman View Post
    I must live in a different world. I had no problem at all spinning a 24P Raker on my GT150 to 5400 on a 20' Champion. You may want to perform a sync n link on your carbs and make sure the plates are opening fully.
    You don't live in a different world Fred, different hulls, different props, how much rooster tail. Hell, I run a hydraulic jack plate, a 1991 150 Intruder, on my 18 foot Cajun that has the pop off Skeeter Starfire 175 hull and I turn a 24 Raker 5400. On radar right at 70 mph. That's with just me in it, but that's like two normal people. on the carbs opening full.

  11. SC Club Moderator ChampioNman's Avatar
    Join Date
    May 2004
    Location
    Crawfordville, FL/Lake Hartwell, SC
    Posts
    71,246
    #11
    It was just a magical prop Jerry. With the GT it was flat on the transom with the tail just over the top of the cowl. Not a speed demon on that big hull, Popped a 2000 MY 200 that I found NOS and added a 9.5" manual plate on it with the same 24 P prop and ran all day solid 66. Sold that one and put the current 225 HO on the back and like an idiot sold the Raker. Put a Tempest plus 25P on it and had to play with the PVS plugs for the hole shot but it is now a 70 MPH boat. I did change the backing plates on the plate and brought it in 2.5" so now it is @ 7" off the back.

  12. Member
    Join Date
    Aug 2017
    Location
    Richmond, Virginia
    Posts
    51
    #12
    Ahhh.. I did forget to mention I do have either an 8", or 10" manual jack plate as well. I'm not positive which one. .

    Work has me so busy right now, I can't play hooky like I want to. I'll be able to really check some more things Friday.
    2000 Ranger R93VS
    2003 Mercury Optimax

  13. Member
    Join Date
    Aug 2009
    Location
    Wichita KS
    Posts
    4,917
    #13
    Quote Originally Posted by ChampioNman View Post
    It was just a magical prop Jerry. With the GT it was flat on the transom with the tail just over the top of the cowl. Not a speed demon on that big hull, Popped a 2000 MY 200 that I found NOS and added a 9.5" manual plate on it with the same 24 P prop and ran all day solid 66. Sold that one and put the current 225 HO on the back and like an idiot sold the Raker. Put a Tempest plus 25P on it and had to play with the PVS plugs for the hole shot but it is now a 70 MPH boat. I did change the backing plates on the plate and brought it in 2.5" so now it is @ 7" off the back.
    I know what you mean about some props just being great. A few years ago I found a new original Turbo 26 pitch for a $100.00. I thought that mike make a good winter prop. That was the best prop, did everything I like in a prop, unbelievable top end. Then on lake Fork I hit a stump bent an ear, it's reparable, I just wonder if will be the same.

  14. Ohio Fishing Reports Moderator omcforever's Avatar
    Join Date
    Nov 2007
    Location
    Miamisburg Ohio/Formerly Aiken SC
    Posts
    20,052
    #14
    I have had good luck with the 24P shooter 4 blade re-worked by the Prop Shop in Augusta Ga.on mine. (heavy 1989 350V Ranger hull and GT 150). Put a stock Renegade on it and did just as good. Good on a heavy Ranger is not the same good on others,,,,,,58-60 MPH at 5600 rpm with a 6 inch plate.

    Age and treachery will always overcome youth and skill !!

  15. Ohio Fishing Reports Moderator omcforever's Avatar
    Join Date
    Nov 2007
    Location
    Miamisburg Ohio/Formerly Aiken SC
    Posts
    20,052
    #15
    If you where closer, you could come by and borrow all my props to test. Have a box full from over the years and those 2 four blades as well. Like Fred says,,check the link and sync and throttle blades per your manual. Good luck..

    Age and treachery will always overcome youth and skill !!

  16. Member
    Join Date
    Aug 2017
    Location
    Richmond, Virginia
    Posts
    51
    #16
    Well, didn't get done what I wanted to, due to rain, and no timing light. However, I did perform the throttle valve sync, and cam follower adjustment, per the manual, (thanks again omcforever), and replaced the plugs. All plugs were definitely in need of replacement.

    I was able to take a quick test run in between rain drops, and Hole shot greatly improved, but I still don't reach WOT. I only turn @4800 WOT.

    I also noticed after adjustments, the closest I could get the cam roller aligned with the short mark, was just very slightly in front of it. I did not adjust the knurled wheel on the throttle cam to get it to line up, nor did I adjust the WOT throttle screw/bolt up top either. Should I go ahead and make any adjustments to either of those?

    Also, a slight correction to previous posts, it is a 14-1/2 X 22 Raker, 3 blade, not 24...
    2000 Ranger R93VS
    2003 Mercury Optimax

  17. Member
    Join Date
    Aug 2009
    Location
    Wichita KS
    Posts
    4,917
    #17
    You need to verify that the carbs are opening fully. The timing must advance 8 degree's and at this point the center of the carb roller lines up with the mark. If you still have some hesitation on take off you can set the advanced timing at 10 degree's. Measure your motor height, pad to center of prop shaft.

  18. Member
    Join Date
    Aug 2017
    Location
    Richmond, Virginia
    Posts
    51
    #18
    Quote Originally Posted by 316jughead View Post
    You need to verify that the carbs are opening fully. The timing must advance 8 degree's and at this point the center of the carb roller lines up with the mark. If you still have some hesitation on take off you can set the advanced timing at 10 degree's. Measure your motor height, pad to center of prop shaft.
    I'll do that. The rain was coming down a little heavier than what I typically like to play in, so I didn't spend as much time as i'd like to.

    Takeoff was 10X better after the plug replacement. Now just getting my WOT corrected and it will be perfect.
    2000 Ranger R93VS
    2003 Mercury Optimax

Tags for this Thread