CMC PLATE

Discussion in 'Outboard Maintenance' started by Puertoricoinshore, Aug 31, 2012.

  1. Puertoricoinshore

    Puertoricoinshore dont just fish fly fish!!!!!!

    316
    0
    141
    Has anyone try this before, to put a plate on the cmc to raise the motor up.
    sorry the pic is kind of off.
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]

    I will take the piece to the machine shop to cut 1/2" off so the two parts look like one. Any opinion please let me know.
     
  2. HaMm3r

    HaMm3r Well-Known Member

    I would be a little concerned that you don't have enough overlap of the two plates, basically you'd only have two bolts holding them together the way you've got the new piece positioned. If it were me, I'd get a larger piece and bolt it onto the back of the CMC so that it covers most of the existing plate and sticks up the extra few inches.

    Otherwise, good idea! :cool:
     

  3. AfterHours2

    AfterHours2 Stripper in my own Mind!

    2,544
    133
    918
    X2. Definitely mount to the outside and cover the entire back of the cmc. This should give you plenty of support and also act as a fixed jackplate. Good idea..
     
  4. Puertoricoinshore

    Puertoricoinshore dont just fish fly fish!!!!!!

    316
    0
    141
    [smiley=1-mmm.gif]
    Thank you guys. Defenetly a better idea to use a bigger plate on the outside.
    Thanks!!!!!!!!!!!!!
     
  5. Puertoricoinshore

    Puertoricoinshore dont just fish fly fish!!!!!!

    316
    0
    141
    Took the plate to the machine shop this after noon. Hope by the end of next week the piece is done and i can try the motor. Going to go with this piece for now and do some test if not plan b will be the wining ticket. Will see.
     
  6. HaMm3r

    HaMm3r Well-Known Member

    Well good luck. Just make sure your motor is bolted or chained to something else besides that add-on plate. If the torque tears that plate loose, I'd hate for your motor to take a swim.
     
  7. Puertoricoinshore

    Puertoricoinshore dont just fish fly fish!!!!!!

    316
    0
    141
    I am thinking of usisng another 1/2"on the back of as you guys said and install both.
     
  8. Puertoricoinshore

    Puertoricoinshore dont just fish fly fish!!!!!!

    316
    0
    141
    After 7 months an update on the piece.
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    where it seats with the plate
    [​IMG]
    with out the plate
    [​IMG]
     
  9. firecat1981

    firecat1981 BBA Counselor

    5,060
    281
    1,938
    is it sandwiched between 2 plates, or is it still just those 2 little bolts holding it on?
     
  10. Puertoricoinshore

    Puertoricoinshore dont just fish fly fish!!!!!!

    316
    0
    141
    The cut curve is 1/2" deep living 1/2" plate and it seat on top the cmc making the two parts into one. The two 1/2" nuts and bolt on the corners holds the two pieces together really strong and then the motor to the top holes. I am going to use 1/2"aluminium bar from the motor holes to the cmc to reinforce. But is not really needed at all.
     
  11. Puertoricoinshore

    Puertoricoinshore dont just fish fly fish!!!!!!

    316
    0
    141
  12. HaMm3r

    HaMm3r Well-Known Member

    Well, the torque on those two bolts is going to be pretty severe I'd think, but if you're happy with it then good luck to you. It looks good, I'd just be afraid of snapping that plate off and losing the whole motor.
     
  13. Puertoricoinshore

    Puertoricoinshore dont just fish fly fish!!!!!!

    316
    0
    141
    I understand your point. But that motor was hold to the cmc for the past five years since the owner boughted with two not even the four 3/8" ss bolt with no issues. Now with the remodeling i change them to 1/2" and use the four. But defenetly in the end i am going to put reinforcements. Ohh and that aluminium plate is the stronges aluminium alloy for the application. Thanks HaMm3r!!!!!
     
  14. Puertoricoinshore

    Puertoricoinshore dont just fish fly fish!!!!!!

    316
    0
    141
    Right now the only issue with the plate is ventilation. I did put the cavitation plate on the motor with the bottom of the transom. And the first test with the aluminium propeller 11 3/8 x 12p and tabs, no running at all only ventilation. Then test with another propeller 11 5/8 x 14p ss prop and no tabs. better hole shot and good top end speed with two persons and full tank of gas. To me what we need is another prop 4 blade or cup the ss prop. So we can get more bite on the water.

    If you have any knowledge on the issue you be more than welcome
     
  15. DuckNut

    DuckNut Brandon, FL

    4,522
    401
    1,938
    If you are getting ventilation then you need to drop the motor, add a compression plate. A different prop is not necessarily the answer.

    Also, your comment on how the previous owner mounted the motor worked because the bottom of the motor bracket had the transom/jackplate to push against. What you have done is to remove this solid point of resistance and changed the fulcrum point which will create tremendous amounts of stress on those two bolts. If it were me I would try to fit a couple more on there. It appears you have room to do this at the point near the curve you ground out.
     
  16. HaMm3r

    HaMm3r Well-Known Member

    Fine, except the four bolts are through the new plate, not the original CMC mounting surface, so ultimately they're doing nothing to strengthen how the motor is attached. You've still just got two bolts holding the plate which holds the motor, and because of the added height you've essentially created a lever which will put far more force on the two connecting bolts.

    Look, it's a great idea, but that weak junction just screams trouble. At least try to put an extra set of bolts through the bottom of the motor clamp bracket and the CMC plate. Or go pick up a bigger piece of aluminum and do it right, as suggested earlier.
     
  17. Puertoricoinshore

    Puertoricoinshore dont just fish fly fish!!!!!!

    316
    0
    141
    After a bunch of testings the plate does what it supose to do. But when you have more than 2 people plus gear, baitwell (28gls of water), 12gls of gas, 10ft cast net is defenetly under power. So know my buddy the owner was waiting for and excuse to change the motor and this one work great for him. So in the next couple of days a motor upgrade to a yamaha 60hp 2007 same setup (manul start etc). Pics coming soon!!!!!!!!!!!!!!!!!
     
  18. Puertoricoinshore

    Puertoricoinshore dont just fish fly fish!!!!!!

    316
    0
    141
    Whent on thursday to pick up the 60hp 2 cycle 2005 yamaha. Rigth know moto is already mounted, but took the carbs out to clean them and install new kit. Pics coming soon
     
  19. Puertoricoinshore

    Puertoricoinshore dont just fish fly fish!!!!!!

    316
    0
    141
  20. AfterHours2

    AfterHours2 Stripper in my own Mind!

    2,544
    133
    918
    Nice to see you got some more power. Whats the weight difference between the two?
     
Loading...
Similar Threads Forum Date
Jack Plate build Boat Yard Basics Sep 9, 2017
Used jackplate Boating, Fishing and Marine Products for Sale Aug 25, 2017
Cleaning garage - old jackplate Boating, Fishing and Marine Products for Sale Aug 24, 2017
Vance Jack Plate 4" set back Boating, Fishing and Marine Products for Sale Jul 28, 2017
Homemade Jack Plate Boat Yard Basics Jul 10, 2017