another problem with johnson 28 hp

[f16dcc431]

so i got the johnson running real good and smooth but i have another problem at low thorttle the chungs along like there nothing wrong at about half throttle a wake starts to form and you can feel the mortor pushing you but you hear the rpms rise a litle and when the do you loose the pushing of the motor and then the rpms drop a little i mean not a big diffrence and the motor starts to push again and at full trottle the same thing is happing just it does not want to push for a longer period of time so there is no plaining and it just creating a wake could it be the shaft on the motor is not long enough and when the wake is being formed the prop is coming out of the water or does it seem to be something elese this is a 62 johnson 28hp
Thanks Josh

 

[Daviet]

Re: another problem with johnson 28 hp

If the cavation plate is even with the bottom of the boat you are ok.

 

[f16dcc431]

Re: another problem with johnson 28 hp

thats the other thing i wonder if the is something missing on the cavitation plate there are four holes in it and idk why they are there i will see if i got pics of the outboard

 

[Daviet]

Re: another problem with johnson 28 hp

Maybe at one time someone mounted one of those whale tale things on it.

 

[f16dcc431]

Re: another problem with johnson 28 hp

View attachment 112830View attachment 112831View attachment 112832 here are the pics

 

[Daviet]

Re: another problem with johnson 28 hp

Sorry, can't open the attachment.

 

[62 ROYAL SCOTT]

Re: another problem with johnson 28 hp

Hey, no pic's or is it me

 

[f16dcc431]

lets try that again

 

[f16dcc431]

Re: another problem with johnson 28 hp

i also have a video of ot doing its thing but i have no clue how to upload it

 

[Daviet]

Re: another problem with johnson 28 hp

Looks like someone had something mounted on the cavation plate at one time or another. Is your cavation plate even with the bottom of the boat, can't tell from the picture? What is the hose attached to the lower unit?

 

[f16dcc431]

Re: another problem with johnson 28 hp

i was flushing the lower end when i took those pic im going outside to look at the cavitation plate

 

[f16dcc431]

Re: another problem with johnson 28 hp

the plate is 1-1 1/2 inch above the lowest part of the hull it leval with the bottom of the top dain hole

 

[cwlson]

Re: another problem with johnson 28 hp

here is a video of the motor

 

[Daviet]

Re: another problem with johnson 28 hp

Your engine might be mounted a little high allowing it to cavatate.

 

[f16dcc431]

Re: another problem with johnson 28 hp

ok this sound stupid but what is the best way to fix it mount it lower???

 

[Daviet]

Re: another problem with johnson 28 hp

Is this boat combination new to you or have you had it for a while? Has the engine/boat ever ran properly, is this a new problem or has it been that way since you got it?

 

[f16dcc431]

Re: another problem with johnson 28 hp

just picked up the boat did a little outboard work to get it running smoothly and this was the 3rd test on the the water the first 2 we found little thing before even leaving dock this was the fist time away from dock and in the water the engine is running great besides this problem

 

[BonairII]

Re: another problem with johnson 28 hp

If your motor is too short..you'd have to cut the transom down.

 

[Daviet]

Re: another problem with johnson 28 hp

I was tought that the cavation plate should be even with the bottom of the boat, can be slightly above but I think 1 1/2" might be to high. The only way I have lowered and engine was to cut down the transom.
I am sure others will come along and give their advice on the subject.

 

[f16dcc431]

Re: another problem with johnson 28 hp

thank you for the help