7.5 outboard rigger

[Jimmy Whitbeck]

Here are some pics of my rigger.

Just ran it for the first time, with a X445 2 blade, waiting for a 3 blade X447!

Sat the outboard as high as I could with the octura mount and tilted it down as far as possible.

The torque of the engine would lift the front left sponson a good 3-4 inches out of the water!!! and the tip of the turn fin on the right (facing from the rear of the boat) would just be in the water!

It is verry unpredictable as when you get on the throttle it would lift rather quickly.

The god news is that I only fliped it once! (paid a young kid 5 bucks to swim out and retreive it!!)

I also learned the value of a hopper tank, should be able to run an enduro with a 8oz & 4 oz hopper!

Any tips on how to improve on this un predictable thing ???

for props I would recomend a octura 1745 three blade or a cut 1752 three blade as this is what I run on the sundowner rigger that I did have. and these should help the tork lifting . Jimmy

 

[_laxmasta2039]

damien lookin' good!!

you might find that the nose runs really high, before putting neg. trim on the engine [you might have to do this anyway, i did] get/make some metal plates that will act like airplane aelerons to keep the nose down, put one on each sponson boom in the front. if you don't know what i'm talking about look at some pics of the Prather Spitfire, it's got some plastic ones.

Joe

 

[damien_au]

I trimmed it with as much negative as I could!

I made up a wooden wedge to put between the mouunt for more negative angle.

Will see what this does next weekend.

Just ordered a octura 1745 3 blade and waiting on a X447.

Hope one of these fixes the problem ???

Any other advice would be appreciated.

Thanks

Damien

 

[Mike Hughes]

I don't believe that you will ever be happy with the way that boat runs with a 7.5 on it. Your boat is about 31". That is the size of a 3.5 boat. You will have to run a prop that is large to keep the weight of the 7.5 out of the water. With a large prop you will never get rid of the tork roll that you are having. There is a considerable difference in size from a 3.5 to a 7.5 boat. I don't know exactly but from the ones that I have seen they are about 40". My suggestion is to buy a 3.5 motor for it.

Mike

 

[Jimmy Whitbeck]

I don't believe that you will ever be happy with the way that boat runs with a 7.5 on it. You boat is about 31". That is the size of a 3.5 boat. You will have to run a prop that is large to keep the weight of the 7.5 out of the water. With a large prop you will never get rid of the tork roll that you are having. There is a considerable difference in size from a 3.5 to a 7.5 boat. I don't know exactly but from the ones that I have seen they are about 40". My suggestion is to buy a 3.5 motor for it.

Mike

size differance a 45 ob rigger ( a copy of a sundowner ) 21.5" wide by 38" long now for the 20 ob riggger 17" wide by 30" long this should clear up the size thing .Jimmy

 

[Mike Hughes]

Not bad for an educated guess. I estamated his boat from the 7.5 lower unit. They are 7" long from pin to the end of the cavitation plate.

Mike