Carb. facing front.

[Tyke]

IS there any reason not to turn the top housing 180 deg. so the carb. will face the front?

Thoughts....opinions.....thx.

 

[Ralphie]

IS there any reason not to turn the top housing 180 deg. so the carb. will face the front?Thoughts....opinions.....thx.

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I have had simalar ideas, would Ram Induction or a scoop forcing air into the carb help on a boat like it does on a car. Has anyone tried anything like that ?

 

[John Knight]

IS there any reason not to turn the top housing 180 deg. so the carb. will face the front?Thoughts....opinions.....thx.

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I have had simalar ideas, would Ram Induction or a scoop forcing air into the carb help on a boat like it does on a car. Has anyone tried anything like that ?

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Where you have air induction with a car, you can also get water induction with a boat. Unless it is shielded or covered and would that negate (partially or totally)the effect of the ram induction? Tons of spray and roostertails with a boat that cars do not worry about. However, ram induction can have a significant positive effect on performance if controlled properly.

 

[Don Ferrette]

IS there any reason not to turn the top housing 180 deg. so the carb. will face the front?Thoughts....opinions.....thx.

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Besides that your crank induction intake timing would no longer be correct?

 

[bbnate804]

i think i'm with don on the induction timing...maybe if you turned the carb and crankcase around?

nate

 

[Tyke]

i think i'm with don on the induction timing...maybe if you turned the carb and crankcase around?
nate

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I disagree with this but am willing to be proved wrong.

 

[Mike Hughes]

It will be out 180 degrees. It is simple. If the crank pin is on the left and your turn it around. Will it not be on the right? With the old disk motors it was easy to make this happen. The disk plate had 2 places that the crank pin could go in. If it was wrong, you knew it right off. The carb would spit fuel out at you when your trying to start it.

Mike

 

[racer504]

i think i'm with don on the induction timing...maybe if you turned the carb and crankcase around?
nate

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I disagree with this but am willing to be proved wrong.

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Guys, You are all correct to a point. If you rotate only the carburetor 180 degrees the induction timing will be wrong...Unless you want to run the engine in the opposite direction and then it will be perfect! Also unless you have a huge carb and enough pressure to maintain steady fuel flow the added air pressure thru the carb would probably be negligible. Why not just add a scoop...And hope it don't suck water in.

Mike

 

[Lake S.P.O.R.T.]

I have wondered before if the carb facing rearward has a negative effect on carb induction. But, if the cowl is tall enough to knock the air off of the front of the engine (which yours is) then I would think that there would not be enough air velocity going past the carb to cause that kind of problem. Yes that will put the timing off 180 degrees.

mark

 

[Mike Hughes]

...Unless you want to run the engine in the opposite direction and then it will be perfect!

That would give you a choice of a X430 or a X447 for a prop. I would stick with the regular set up.

Mike

 

[VansRacing]

We have tried scoops. They work. You actually can see a small difference but, go thru one rooster tail and its DONE.

We have talked about trying it again when we get caught up but this time, carry an onboard mini-c battery to keep the plug hot and maybe we could make it thru a little water spray. Maybe...???

What we learned was that the scoops placement does effect the boats trim. Rushing came to the pond one day with one stuck off the side of his engine and it actually made the boat pull to one side.

-Carl,

 

[james irwin]

IS there any reason not to turn the top housing 180 deg. so the carb. will face the front?Thoughts....opinions.....thx.

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BEETTER YET . WHY NOT TURN THE ENGINE FORWARD ? I DID THIS ABOUT THIRTY YRS AGO , NOT ONLY DID IT MOVE THE CG FORWARD , IT ALSO PLACED THE CARB FORWARD ON AN ELDEABLO ( HYDRO )

 

[Dr Hydro]

We have tried scoops. They work. You actually can see a small difference but, go thru one rooster tail and its DONE.
We have talked about trying it again when we get caught up but this time, carry an onboard mini-c battery to keep the plug hot and maybe we could make it thru a little water spray. Maybe...???

What we learned was that the scoops placement does effect the boats trim. Rushing came to the pond one day with one stuck off the side of his engine and it actually made the boat pull to one side.

-Carl,

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Hey Race Dudes,

Greetings from New Orleans(the new "Down Under"). I would just like to point out that not all scoops are created equal. There are many different shapes and functions of scoops. Look at the scoops on offshore racing power boats. There is the usual big opening in the front but there is also a smaller exit hole in the back. The trick is, the opening going into the engine bay is towards the front of the scoop and out of the line of fire of the water coming in. This water flies past the inlet and can not make a 90 degree turn fast enough to go in the opening but at the same time the air pressure is building up in the engine bay because the small rear opening does not let the air out fast enough. I wish I could show you a drawing. I hope I am getting the point across.....Good luck and have fun!

 

[Don Ferrette]

Hey Race Dudes,      Greetings from New Orleans(the new "Down  Under"). I would just like to point out that not all scoops are created equal. There are many different shapes and functions of scoops. Look at the scoops on offshore racing power boats. There is the usual big opening in the front but there is also a smaller exit hole in the back.  The trick is, the opening going into the engine bay is towards the front of the scoop and out of the line of fire of the water coming in. This water flies past the inlet and can not make a 90 degree turn fast enough to go in the opening but at the same time the air pressure is building up in the engine bay because the small rear opening does not let the air out fast enough. I wish I could show you a drawing. I hope I am getting the point across.....Good luck and have fun!

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Hey there Dr. Hydro, who are you? There's no info in your bio. :unsure:

 

[Don Ferrette]

You could always do something like this..........

 

[Lake S.P.O.R.T.]

Now that is different!! Umm, if the flywheel is aft and the glow plug is facing up.....where is the flex shaft coming out? :unsure:

 

[Don Ferrette]

Now that is different!! Umm, if the flywheel is aft and the glow plug is facing up.....where is the flex shaft coming out?  :unsure:

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It's a belt drive to gear driven prop shaft from what I could see.

Now that would be cool, a conventional i/b .21 belt driven to the lower unit. Change your belt cogs for different drive ratios. And no more having to reverse your starter motor. Hmmm........... B)

 

[Tim_Duggan]

Now that is different!! Umm, if the flywheel is aft and the glow plug is facing up.....where is the flex shaft coming out?  :unsure:

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Now that would be cool, a conventional i/b .21 belt driven to the lower unit. Change your belt cogs for different drive ratios. And no more having to reverse your starter motor. Hmmm........... B)

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Don,

Your points sound VERY similar in concept to the Thunder Tiger O/B - except the TT uses gears (more durable).

Can you guess what I'm building

Tim B)

 

[Geraghty]

IS there any reason not to turn the top housing 180 deg. so the carb. will face the front?Thoughts....opinions.....thx.

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If you turn the .21 outboard front housing 180 degrees,the motor won't run.

That sounds to me like a pretty good reason not to turn it around.

 

[racer504]

IS there any reason not to turn the top housing 180 deg. so the carb. will face the front?Thoughts....opinions.....thx.

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If you turn the .21 outboard front housing 180 degrees,the motor won't run.

That sounds to me like a pretty good reason not to turn it around.

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Geraghty is right! I stated earlier in this thread that it would run (in reverse) if the carb and intake were rotated 180 degrees, but I was wrong. :blink: It will run in reverse direction if you rotate the carb 90 degrees one way or the other depending on it's present direction of rotation. Just another good reason to leave it alone.