Question for Don ( Raising my motor)

[Gambler Bob]

I am going to raise my motor on my boat, right now it is 5" below the pad 67 mph, 5400 rpms tempest plus 25p, water pressure is 27 psi the motor is a 3 months old it is a 2010 Merc Pro XS. My jackplate is a 10" slidemaster it does not adjust up or down so i believe it might be referred to as a setback plate. From what i read in my Merc manual it is 90 lbs of torque for the bolts that connect from the setback plate to the motor is that correct. Also my plan for raising my motor is doing this in my garage by hooking up a chain fall to a 4x4 that spans 3 roof trusses i am going to locate the 4x4 close to the exterior wall because it is load beairing not in the middle of the garage. I am planning on moving the motor up 2 bolts holes on the setback plate, it will be on the top holes, this will move it up 1-1/2 inches to 3-1/2 inches below the pad. Then i will retest the boat for higher rpms and better boat handling. Right now the boat chine walks reel bad at high speeds. I also read some other posts about water pressure 15lbs minimum but you prefer to see 18 lbs at WOT i will keep a close look at the water pressure when i retest. I will buy a eye bolt to hook the other end of the chain pull up to do you know what size eye bolt i need. Thank you

[EuropeanAM]

Bob:

FIRST and FOREMOST: I do NOT recommend, nor condone what you're suggesting in regards to a 4x4 spanning roof trusses. <u>This idea could have catastrophic results for your building, yourself, your boat, and your engine.</u> I honestly don't feel that it's worth the risk.... at the very least, consider renting an engine hoise from a local rental store (which is FAR cheaper and DEFINITELY safer).

I'm "guessing" that your boat is one of the Nitro Models?

You are correct on the engine mounting bolt torque: 90 ft. lbs. Torque the NUTS (and HOLD THE BOLTS WITH ANOTHER WRENCH).

5" below pad is definitely VERY low, however, I'd be very cautious about moving up TWO mounting holes at a time. Normally, engine mounting height changes are done in 1/4" increments.... one mounting hole (in your case) equals 3/4"! You will have to make the decision here.... but in either case, you should, as you suggested, monitor engine RPM's, speed, WATER PRESSURE, and boat handling.

I would recommend having a Mercury Part# 904551 lifting eye bolt on hand to thread into the flywheel.... and an appropriate chain (3/8") with threaded clevis to attach to the eye bolt.

Note: You may want to consider an adjustable plate (or better yet, a hydraulic plate) at some point in the future.

[Strokerdean]

Unless I missed it, what type of hull are you running. Different hulls seem to work better at diff engine heigths. You could probably check in on the forum for your hull type and get a starting point for heigth from the others that have the same.

[californiahillbilly]

You can pick up an engine hoist for cheap on craigslist.

Heed Don's advice and good luck!

[Gambler Bob]

The boat is a Nitro 901 CDX 19' 2" and 94" beam

[EuropeanAM]

Bob:

Can you post a picture of your jackplate?

That might be helpful.... since most of the Nitro models came with a Slidemaster, that WAS adjustable (see picture below for an example):

[transamz9]

Don
His is a slidemaster but is not adjustable. Let me see if I can find the pics he posted.

[transamz9]

Here you go......

[EuropeanAM]

Gotcha.... that one's certainly NOT adjustable.

He'll have very few options, other than raising the engine one or two holes.... or better yet (and much more advantageous in the future) installing a different plate.