how far off are these motor results

[suzukidave]

preliminary seatest on a new to me 1995 223 tournament with a 1994 evinrude 200 ocean pro. i know i have work to do on the motor and that is in process, but interested on what people think the motor should be turning.

maximum speed is 34 mph gps tested and rpm is 4900. i am ventilating a little to get even to that and it really doesn't want to go over 4500rpm/32mph. prop blows out much more easily than my 190 tournament.

background info
-compression 110 x 4, 105 and 115
-bottom paint is old and thick but clean with no weed
-boat rests with outboard rear scuppers partly immersed
-fuel is may 2013 premium treated with k100 stabilizer/octane booster last november. tank is full.
-prop is original ss 15x17. i would describe the blades as suitable for cutting a rare steak and will be trying an aluminum prop and sourcing a new ss prop
-trim tabs are mounted and operable. they slow the boat down if deployed more than a smidgeon
-motor is mounted as low as she will go
-bottom of engine cavitation plate lines up with boat bottom when engine is trimmed parallel to the hull bottom

as i said, i know i have work to do on the engine as i can feel it bogging and it wakes right up if you remove the silencer box. i have been through the electrical and am rebuilding the carbs right now. what i am wondering is how many rpm am i missing?

 

[Parthery]

Your numbers are off....could be any number of things.

I've owned both a '98 225 with a 200 Carb'ed SWS and a '99 223 with a 225 OX66. Both were 42 MPH boats at WOT throttle (5400-5500 RPM).

I'd do the following...

1.) Make sure the bilge is dry and you aren't carrying around a bunch of extra water.
2.) Raise the motor. The 225 OX 66 on my 223 was mounted one hole up (second hole.)
3.) Make sure your throttle linkage is opening all the way. If not, no matter what you do you will never get to "full throttle".
4.) Check with Ken at propgods.com and see what he recommends for a prop. My 200 on the 225 swung a 17" wheel....but he may recommend that you drop down to a 15" pitch prop.

Good luck...keep us posted.

 

[suzukidave]

thanks. sounds like i am about 500 rpm short and some of that could be engine height. i assume not all though. this looks to be the original motor and factory rigging, and i assume grady wouldn't rig a boat to only make 5000 rpm.

are the holes in a transom consistent so that "second hole" means the same thing for engine height between two boats and two motors?

i am cleaning the carbs right now so i will finish that. i also sourced a 14.8x17 solas aluminum to try. so i will try it with carbs cleaned so i can tell if that alone made any difference, and then try it with the aluminum prop to verify the prop is ok, and after that i will lift the motor.

 

[Curmudgeon]

You can't determine the correct prop until you get the motor right, meaning height and know you're WOT for what you have. You will know the height is right when the vent plate is just above the water when at speed, but still getting splashed. You can usually go one more hole up without significant blow-out, but not always. As mentioned, make sure the carb linkage allows full travel of the carb butterflies, you're PITW if that isn't happening. Once you're sure of all this, then it's time to chase the prop ... :wink:

 

[suzukidave]

rebuilt the carbs, found a main jet was loose in the tube, and the linkage adjustment was not letting the butterflies fully open. also, the fuel t manifold was not connected to the carbs in the correct order. i finally got it back in the water.

now i get 5400 rpm and 37 mph. best speed is with trim tabs right up and motor trimmed out. the ventilation plate is buried until it is trimmed well out so i will be raising the motor.

the motor is still not right but i know it will run right now. idle is low and rough and hole shot and acceleration is very slow compared to the 190, especially after 33mph (i watch the tenths of an mph tick off like seconds on the gps). old gas may be part of it, but i am going over the timing next.

 

[ROBERTH]

I for sure would get some newer fresh fuel in there before changing timing and other stuff. Use 87 octane and not premium so you can get more combustion/power and less carbon build up.

Then tweek out the timing, etc. Many times the older fuel can cause loss of power.

 

[suzukidave]

update on this and suggestions sought on the right prop. i got it to 38 mph at 5300 in the second hole with no trim tabs applied. also verified bad gas is an issue.

then put boat down for winter and started pulling thruhulls and hatches to replace/redo. belatedly realized this offseason i will be on the look out for a good deal on a prop so i guess i need to make an educated guess on prop. i am thinking after some reading that either a mirage plus 17p or a rev4/ofs4 would be the right set up for this boat. do folks agree and do you think 15p or 16p for 4 blade assuming boat and motor are performing properly?

extra detail on last run: i replaced small filter and all fuel lines to the main feed hose, took it out again and verified timing is correct. finally took note that my acceleration and top end improved while i was out there after starting off anemic and realized this pattern has been consistent since first run. after puzzling about this i concluded it is bad gas with separation at the bottom of the tank so i am getting better performance once the tank mixes a bit. drained the recently emptied racer filter and let it settle in a glass container this time. i got about 25% separation. gas is going bye bye.

 

[bayrat]

You can't determine the correct prop until you get the motor right, meaning height and know you're WOT for what you have. You will know the height is right when the vent plate is just above the water when at speed, but still getting splashed. You can usually go one more hole up without significant blow-out, but not always. As mentioned, make sure the carb linkage allows full travel of the carb butterflies, you're PITW if that isn't happening. Once you're sure of all this, then it's time to chase the prop ... :wink:

This ^^^^^^^^^ My Grady came from the factory with the plate buried.I guess they would rather have it that way then to get sued if a novice boater went hard into a turn and it broke loose and people were injured. I raised mine 2 holes and it's fine.