Using jacker plate to lower instead of raise outboard on transom

[95johnson]

I have read on the internet (so I know it's true) that a jacker plate could be used to LOWER an outboard if the transom is slightly too tall... The motor sets low enough to operate fine and get water at low speeds, but when fast enough to lift boat onto plane it wants to "blow out". My question is; has anybody here actually done it? Will the tiller handle clear transom when lowered? Still able to tilt motor? the plate I'm thinking about sets outboard back 4". Also my boat is Tracker 1648 grizzly .... Motor is a 1995 Johnson 40hp tiller steer.

 

[JB]

Re: Using jacker plate to lower instead of raise outboard on transom

Where, exactly, does the anti ventilation plate sit relative to the bottom? With a 4" setback it will ideally be an inch or two above the bottom.

It should be simple enough to measure how much you might need to lower the outboard and whether the tiller will still clear the transom if lowered that much.

My instinct says to convert your outboard to a long shaft or extra long shaft as required.

 

[boobie]

Re: Using jacker plate to lower instead of raise outboard on transom

Agree + 1 with above seeing it's a tiller model. Unless you want cut your transom.

 

[95johnson]

Re: Using jacker plate to lower instead of raise outboard on transom

As it is now the cavitaion plate is about 3" higher than bottom of boat. I do not have any holes drilled in transom right now because I had a motor on it that was long enough (but it was a 9.9) this 40hp sets too high... Since I will be drilling holes to mount this bigger outboard anyway I figured I could use a jack plate and mount it low enough to allow me to adjust the cavitation plate about to the bottom of boat if needed...i could raise from there.... I actually tried to look at extending this motor....but I don't see a shaft extension on the part diagram for this engine.

 

[95johnson]

Re: Using jacker plate to lower instead of raise outboard on transom

Also extension would be 5" correct? This should put the anti-cav plate about 2" below bottom of transom.....

 

[boobie]

Re: Using jacker plate to lower instead of raise outboard on transom

Normally the anti-vent plate should be pararell with the bottom of the boat or maybe 1 " above the bottom. If you use a jackplate will your tiller handle still be long enough ?? You could try Bay Mfg.com and see if they make an extension for you mtr.

 

[tomhath]

Re: Using jacker plate to lower instead of raise outboard on transom

I'm sure you like the motor you have, etc. But probably the cheapest way to get what you need is to sell that motor and buy one that fits your boat...it had to be said.

 

[95johnson]

Re: Using jacker plate to lower instead of raise outboard on transom

If I use a jack plate I believe that the tiller handle should be long enough (it only moves 4" back) and if I'm looking for one to two inches above the bottom then it will only be dropping motor about an inch (or two) below normal level... So it seems like I should still be able to turn with hitting anything.... It SEEMS like to me. I just didn't know if anybody had ever actually tried it.
Also, I checked BayMFG.com ...they showing a 5" extension kit....dont know how much but I sent them an email.

 

[95johnson]

Re: Using jacker plate to lower instead of raise outboard on transom

ps. This is the plate I am considering.

Jack Plates

 

[bob johnson]

Re: Using jacker plate to lower instead of raise outboard on transom

you could use that jack plate...personally id re drill the hole in the jack plate and not the transom.....if you drill the holes lower in your transom, you dont need a jack plate.....right?

so why drill them lower and then add a static jack plate???

most jacks go from level , and then upwards.... you could mount it upside down maybe, and jack it down..and leave the holes in the standard boating association locations.

you might want to make sure you can tilt the motor fully....the motor notmally tilts into the boat....with the setback you will be tilting into the top of the transom a little

bob

 

[95johnson]

Re: Using jacker plate to lower instead of raise outboard on transom

the motor is a J40TEEOD ...it has the motor mount that hooks over the transom and clamps with a scew deal. It has holes to bolt it down lower. THAT jack plate is made with a place for the clamp to fit.... and then drill holes at bottom for lower bolts. I would HAVE to use a setback to allow the engine to be mounted lower because of the clamps....cannot just drill holes lower in transom. it looks like the 4" would get them far enough back to clear transom. I could buy the extension for this motor from Bay MFG as suggested, but because that is a 5" extension and i only need to lower my engine 1-2" from where it sets now I would prob still need a jack plate to get height correct... that is why I was curious if i could get the couple inches lower out of a jack plate/ setback setup. (just setting it back would help the height issue, correct?)