1972 evinrude 9.5 need long shaft or different trim?

[Evinrudej]

You could raise it 1/4" at a time and test run.----Some will argue , but that would be my approach.

Will do thanks

 

[Evinrudej]

Hi guys not sure if this is the right place for this topic but I got a sears 12ft aluminum boat. Transom measures at 15” my problem I’m having is attached in the video below. I have water spraying up from the back of the boat when going fast. You can see it splashing against the blue wheel. The motor is a short shaft evinrude 9.5 however I noticed that the cavitation plate sits below the bottom of the boat. Could this be the reason? Should I raise the motor more somehow? Thanks

 

[Bondo]

Hi guys not sure if this is the right place for this topic but I got a sears 12ft aluminum boat. Transom measures at 15” my problem I’m having is attached in the video below. I have water spraying up from the back of the boat when going fast. You can see it splashing against the blue wheel. The motor is a short shaft evinrude 9.5 however I noticed that the cavitation plate sits below the bottom of the boat. Could this be the reason? Should I raise the motor more somehow? Thanks

Ayuh,...... So take the blue wheel offa there,.....

Yer transom is the right height for that motor, I believe,....

 

[racerone]

The only way is to test.---Make some 1/4" shims.----Raise motor 1/4" with first shim and test.----Repeat as needed.

 

[Texasmark]

What is the blue wheel Bondo mentioned. I see it but what function? Surely it's not in the water when running the boat????

Agree on transom is correct height. Those engines ran with the AV plate about an inch below the transom bottom. Get better prop-water connectivity in all water conditions considering the speeds at which they could push a boat and what they usually pushed.

The AV plate starts at the front of the LU casting. Above it a few inches is a plate that sticks out in front of the LU. That is your water deflector plate and it needs to be above the water line on plane to deflect the water that runs up the front of the midsection.

 

[racerone]

The blue wheel is used so that 1 person can move it from a truck and into the water.------It flips up once boat is floating.----Not sure why the OP is reluctant to raise the motor a bit at a time ??-----It was suggested long ago ( a month or more ) and it might not take much.-----Might change trim angle too.

 

[JimS123]

Your pictures were not taken at the right angle so its hard for us to see where the AV plate really is. A sort shaft transom is actually NOT 15". In most cases its more like 16 or 17".

Sure looks like the motor is mounted too low.

Show us a transom top mount and a horizontal pic at the keel.

 

[Sea Rider]

Sit a boater up front, trim motor to 90 deg, install a 1/2 inch wooden or hard cork shim under the motor, go for a wot run on flat calm water condition, check by looking backwards if the splash side or over the transom was cancelled, if still persists replace current shim for a 3/4 inch one.

Right now the water flow at speed is banging the non edged portion of the lower leg when needs to pass thru the edged portion under the samall upper plate to avoid any unwanted water splashes. Each boat motor combo has its unique and precise installation which needs to be height fine tuned if in pursuit of top boating, it's not that easy peasy as to sit any motor on transom snap your fingers and voila!!

Happy Boating​

 

[Evinrudej]

this was taken after raising the motor 1 inch. Should this be good to do a test run?

 

[Evinrudej]

Sit a boater up front, trim motor to 90 deg, install a 1/2 inch wooden or hard cork shim under the motor, go for a wot run on flat calm water condition, check by looking backwards if the splash side or over the transom was cancelled, if still persists replace current shim for a 3/4 inch one.

Right now the water flow at speed is banging the non edged portion of the lower leg when needs to pass thru the edged portion under the samall upper plate to avoid any unwanted water splashes. Each boat motor combo has its unique and precise installation which needs to be height fine tuned if in pursuit of top boating, it's not that easy peasy as to sit any motor on transom snap your fingers and voila!!

Happy Boating​

I definitely learned this lesson all of my 7.5hp and below outboard never had this issue this 9.5 seems to be the only one where I’ve had this happen.

 

[Sea Rider]

I definitely learned this lesson all of my 7.5hp and below outboard never had this issue this 9.5 seems to be the only one where I’ve had this happen.

All HP motors are different, doesn't matter if being same brand, that's why some needs to be height fine tuned to cancel any water plashes out/over transom. Need to water test as suggested the new motor height, dry boating means nothing. LOL!!

Happy Boating​

 

[JimS123]

this was taken after raising the motor 1 inch. Should this be good to do a test run?

Absolutely not. Waste of time. That motor is waaaaayyyyyy to deep in the water.

It appears that the motor and transom are both short shaft, but something here doesn't compute.

The AV plate should be no more than 1" below the bottom of the boat.

 

[Sea Rider]

A dry boat motor install says nothing to me, what the OP needs to do is go for a wot spin with deck load well distributed, new shimed motor height and once on plane on flat calm water cond pull head side of motor and Visually check what's going at back transom.

Need to determine where is the actual hardened exiting water flow is pasing by at spped to know if the 1/2 inch shim went well or need an extra shim height. To the OP, was the combo having water splash issues back or over transom as in pic ?



Happy Boating​

 

[Texasmark]

A dry boat motor install says nothing to me, what the OP needs to do is go for a wot spin with deck load well distributed, new shimed motor height and once on plane on flat calm water cond pull head side of motor and Visually check what's going at back transom.

Need to determine where is the actual hardened exiting water flow is pasing by at spped to know if the 1/2 inch shim went well or need an extra shim height. To the OP, was the combo having water splash issues back or over transom as in pic ?

View attachment 355071

Happy Boating​

Never saw an engine do that. Course I never saw a RIB. Whether its purely a RIB phenomenon or something else, who knows....surely Sea Rider does.

 

[Sea Rider]

Never saw an engine do that. Course I never saw a RIB. Whether its purely a RIB phenomenon or something else, who knows....surely Sea Rider does.

With refference to my posted pic it's simply an awful height mismatch between an S motor and an S rib transom, the water flow was banging the X shown, shimmed right the combo now runs flawlessly at wot, a day/night water performance difference...​

To the OP, your posted video seems to show that current motor sits trimmed donwards, trim it to 90 deg for the AV plate to ride parallel to the water level as seen in pic and test again with different shim heights, that motor definitely sits too darn low and needs desperately to be raised accordingly to cancel the water splash ASAP...
​

Happy Boating

 

[Evinrudej]

Thanks for the input sea rider I set the trim as you state to 90 deg level with the bottom of the boat. Exactly what shims are you referring too and where could I purchase them. I’m thinking based off your previous picture that the water level is above the small upper plate on the 9.5 and that is what is causing the splashing. The water was also slightly going over the transom I would like to add.

 

[Sea Rider]

OK here's the deal : To understand, right now the water flow at speed is banging at the non edged lower leg portion (red line) when should be passing ideally under the yellow line right under the upper plate. That motor has a very tall gap between plates.



Surely one will say that with that setting there will be more lower leg water drag, in reality it's impossible to quantify how much as there's a tall sharp edged portion (green line) right at middle of both plates that will cut the flow nicely at whichever height the flow passes. Will discuss that issue when the water splash has been canceled.

To raise the motor go to a store and buy a thick cork panel, the ones to pin things on them, cut a portion matching the motor's swivel bracket width along the transom's edge width. Sit the motor keeping it at 90º and test, if still splashes add one more cork shim over it and test again till the splash is finally canceled. Can use a wooden shim made to size as an alternative. Whichever is faster to buy or make.

The rear boat's bottom must be impeccable clean before water testing or will produce an uneven water flow passing thru the lower leg, report your findings, good luck !!

Happy Boating​

 

[Texasmark]

Thanks for the input sea rider I set the trim as you state to 90 deg level with the bottom of the boat. Exactly what shims are you referring too and where could I purchase them. I’m thinking based off your previous picture that the water level is above the small upper plate on the 9.5 and that is what is causing the splashing. The water was also slightly going over the transom I would like to add.

Go to the lumber yard and get a piece of wood....HD or Lowes for a couple of sources.

 

[Texasmark]

OK here's the deal : To understand, right now the water flow at speed is banging at the non edged lower leg portion (red line) when should be passing ideally under the yellow line right under the upper plate. That motor has a very tall gap between plates.

View attachment 355100

Surely one will say that with that setting there will be more lower leg water drag, in reality it's impossible to quantify how much as there's a tall sharp edged portion (green line) right at middle of both plates that will cut the flow nicely at whichever height the flow passes. Will discuss that issue when the water splash has been canceled.

To raise the motor go to a store and buy a thick cork panel, the ones to pin things on them, cut a portion matching the motor's swivel bracket width along the transom's edge width. Sit the motor keeping it at 90º and test, if still splashes add one more cork shim over it and test again till the splash is finally canceled. Can use a wooden shim made to size as an alternative. Whichever is faster to buy or make.

The rear boat's bottom must be impeccable clean before water testing or will produce an uneven water flow passing thru the lower leg, report your findings, good luck !!

Happy Boating​

"The rear boat's bottom must be impeccable clean before water testing or will produce an uneven water flow passing thru the lower leg, report your findings, good luck !!"

You may have hit onto the problem. I don't see the engine sitting too low. Looks like its sitting just right putting the top of the water flow in the center of the green line on plane at WOT and 90* tilt as you mentioned.

 

[Sea Rider]

I don't see the engine sitting too low. Looks like its sitting just right putting the top of the water flow in the center of the green line on plane at WOT and 90* tilt as you mentioned.

If the hardened water flow at speed/plane is passing thru the green edged portion won't see any back water splash whatsoever as the edge will cut the flow nicely at whichever height is passing by, will splah if passing/banging right above the small upper plate (red line). For a correct motor transom optimization need to Visually Check what's going at back transom, same applies when shim testing, retesting. Lets see what the OP reports.

Happy Boating​