Motor location

Richard Hartley · Dec 22, 2018

This may be an Andy Brown question

I am installing a 45 VAC where an rs was installed prior in a 45 SGX

Ask me why I am removing the RS, sometimes it is preference, not this time if i showed you a picture of inside of rs you would get it

Question is how far toward the rear of the boat can I place the VAC without seriously affecting the cg and handling

If i can get a satisfactory picture ill put it on here

It is definitely too far forward mounted where the rs was, very little clearance on middle bulkhead and tank. Thank You for any input

Richard Hartley

OK I uploaded the proposed after and the before pictures the position of the motor after I move it will be approximately .83 inch aft of original position

brad nichols · Dec 22, 2018

I f that is where it balances properly leave it there and trim the shaft log back and you are good.

Brad

John Beardslee · Dec 22, 2018

Is that RS damage from the earth quake? Seriously, if you like how the boat handled with the RS, then check where the CG was with it and do what you have to to get the same CG with the VAC.

Thanks John

David Murany · Dec 22, 2018

John Beardslee said:
Is that RS damage from the earth quake? Seriously, if you like how the boat handled with the RS, then check where the CG was with it and do what you have to to get the same CG with the VAC.

Thanks John

What John said. Cg is the important thing to consider.

Richard Hartley · Dec 22, 2018

The RS is on its way to Alaska as we speak. The prior owner did not know how to care for engines at all.

Thanks for the input I

brad nichols said:
I f that is where it balances properly leave it there and trim the shaft log back and you are good.

Brad

John Beardslee said:
Is that RS damage from the earth quake? Seriously, if you like how the boat handled with the RS, then check where the CG was with it and do what you have to to get the same CG with the VAC.

Thanks John

will do just that. I am in AZ for the winter but my son said some glass broken and bathroom cabinets emptied all over.

Claimed he and half the neighbors were in the street within seconds of of the first shudder.

John Beardslee · Dec 22, 2018

Scary stuff for sure!

ALLAN YUEN · Dec 22, 2018

Don’t move on rail mounts because will run hopper or turn spin right side

buy new style 2014 SGX 45 kit long and will fit your CMB 45 Vac

or buy new CMB 45 RS EVO And will fit your old SGX 45

Will contact to Andy Brown and will tell about it

Danny King · Dec 22, 2018

Anywhere it will fit on the mount is fine.

You may need to move the fin too. But i would just move the engine first and try it.

Jeff Lutz · Dec 22, 2018

Richard Hartley said:
This may be an Andy Brown question

I am installing a 45 VAC where an rs was installed prior in a 45 SGX

Ask me why I am removing the RS, sometimes it is preference, not this time if i showed you a picture of inside of rs you would get it

Question is how far toward the rear of the boat can I place the VAC without seriously affecting the cg and handling

If i can get a satisfactory picture ill put it on here

It is definitely too far forward mounted where the rs was, very little clearance on middle bulkhead and tank. Thank You for any input

Richard Hartley

OK I uploaded the proposed after and the before pictures the position of the motor after I move it will be approximately .83 inch aft of original position

View attachment 98325

View attachment 98326

I ran a 45 vac in a sgx myself. I also had to move it back. Don’t worry about the cg, there is some tolerance , I couldn’t tell a difference in handling. You will have to turn the flywheel some for the belt, or build a belly pan to clear the belt.

julianconde · Dec 22, 2018

Richard. I just went thru the same thing with my twin 45. I had Vac engines in it when I decided to change to the RS type engine. mounted the engines close to the same Location where the vac engines where bolted on to. The different in weight was .12 lbs the boat ran perfect

David Bryant · Dec 23, 2018

julianconde said:
Richard. I just went thru the same thing with my twin 45. I had Vac engines in it when I decided to change to the RS type engine. mounted the engines close to the same Location where the vac engines where bolted on to. The different in weight was .12 lbs the boat ran perfect

is there an obvious difference, or gain, in speed now using the CMB RS's ?

charles siler · Dec 23, 2018

You can do it but don’t move the motor it won’t work well with the cowl you can notch the boom tube after putting a dowl of wood or aluminum into the boom to support it.

Danny King · Dec 23, 2018

Or just put a nova in it where the rs was.

dwilfong · Dec 23, 2018

Just have Walt build a slant front tank with a Tee Pee on top. problem solved.........

Richard Hartley · Dec 23, 2018

LOL Danny

You and I seem to be on the same page

Last night before I stopped playing I took out an unused Nova 46dd and it will just drop right in

Problem solved

Thank everyone for your input

Richard

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Richard Hartley · Dec 23, 2018

Just install needle and linkage and go play

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Bert Dygert · Dec 28, 2018

Richard,

Don't to forget to check air flow to the carburetor. Make sure the cowl clearance to the carb. some cowl don't have the height for the angled carb. also make sure your flotation doesn't obstruct the are flow.

Richard Hartley · Dec 28, 2018

Thank You Bert

I will indeed have to move the cowl forward just a bit and thankfully it can be done easily. Even without moving it there is more clearance with the NR.

Had some other projects yesterday but am back at this today. Servos remounted and water line relocated. Prior owner did not use adjustable needle so there was no provision for that servo either.

Richard

Richard Hartley · Jan 23, 2019

Ran the boat today

Ran it rich initially with a 2217 and it would not get on step, leaned it till it quit with same result

Switched to prather 245 and it lit up and went

boat is really fast but has one very disturbing characteristic in mid turn it hooks violently to right

this can be helped some by slowing and by very little steering input but if one adds throttle in the turn it hooks

straightaways are ok as long as no or very little correction is input

Help!

Greg Bonahoom · Jan 23, 2019

Richard Hartley said:
Ran the boat today

Ran it rich initially with a 2217 and it would not get on step, leaned it till it quit with same result

Switched to prather 245 and it lit up and went

boat is really fast but has one very disturbing characteristic in mid turn it hooks violently to right

this can be helped some by slowing and by very little steering input but if one adds throttle in the turn it hooks

straightaways are ok as long as no or very little correction is input

Help!

My first guess would be that your steering servo does not have enough torque to hold the rudder in position.

Motor location

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