Voo-doo/Nissan 70

I just bought a Voo Doo with a 1990  2 cyl Nissan 70.  The rev limiter has been removed, the carburetor air box has been removed and there is a nose cone on the engine (w/o low water pick ups).  The Nissan 70 has 1.92 gears and as stock was rev limited to 5500 rpm.  The engine is flat on the transom.

The boat came with an 10 3/8" diameter 18" Merc chopper.  The little chopper looks like it has been re-hubbed to fit the Nissan.  There are two numbers on the prop  AR-43592A5 & 48-43592-18.  It has a white plastic sleeve in the hub and it has been cupped.

I have only had a brief ride in the boat with an aluminum ski prop.  We ran out of revs at 6200 rpm.

Did someone know what they were doing settting up this boat with the little chopper? 

I would have thought that 18" was not enough pitch.   Merc also made thru hub cleavers in 10.5" and 12 inch diameters (18, 20, & 22 inch pitch).  From what I have been able to find out, the 12" cleavers from the Merc 60's would fit the Nissan.  Could the 10.5's be re-hubbed to fit as well? 

1)  Should I start looking for a cleaver?  What size?

2)  Would adding a manual jackplate be good or bad? 

Since I am new to V bottoms my first priority is to add a foot throttle and learn the boat.  This will take time, but so will finding a cleaver. 

Thanks

David 

P.S.    Tech Talk for Streams is a great idea

 

David, 

Believe it or not those little choppers work great. I've added a little progression to the tips and found they really rock. Don't let the small diameter fool you. A cleaver may help but I doubt it would be a lot faster. Merc makes the 10.5 diameter prop out of the 12" casting so any diameter can be ordered. A jack would solve one problem but probably create two new ones so I'd axe that plan. Here's what I'd do. Most people are unaware that in Europe, Yamaha races a 2 cylinder like yours on v-bottoms. They have a prop, an 11 X 19" that is exactly like a baby Yamaha drag prop. (3 blade round eared cleaver) It is the hot ticket for your set-up. To get one you would need to contact a Yamaha distributor in Europe as it is only sold there. Last time I dealt with that stuff I went through Mitsui Yamaha in England. See if they are on the web and have them get you in contact with the racers they support. You could maybe get a good deal on one used. The prop is made for the 850cc v-bottom class and is so good if you don't have one over there you'll lose. The splines should be the same so I'd go for it. 

Happy hunting

Randy

 

 

Please submit whatever questions you have to IHRTechTalk@yahoo.com.  All questions and answers selected will be displayed on this page as they come in.  Note: though all boaters are welcome, priority may be given to I.H.R. members.  Randy can not be held responsible for any advice given.  Though his information and expertise is second to none, he has no control over what you do with your boat.  It is up to you to boat safely and act responsibly, and his advice is only to be used as a guidance for your high performance boat/motor of which you are the one responsible for the risks involved.

Thanks,
Mark C.

 

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