Viper Motor on Transom Setup

Please tell me the best (most accurate) way to set-up my motor on my viper.  In other words, what is centered?  My factory production model, never-wrecked 84 viper's bottom is not entirely "true".  Taking measurements at the strakes and the pad and even the bottom of the transom, it becomes apparent that none of these surfaces are entirely "in-sync" with one another.  They only differ by less than a 1/4 inch but still, that is somewhat significant.  Which surface do i go off of in centering my motor?  My guess is, the pad, as this is the central balance to the boat.  Please let me know.  Also, once I do determine which surface to use, what is the best and easiest way to actually get the holes exactly right?  I think most people simply grab a tape measure, measuring off of the transom only, not suspecting that a discrepancy may exist between the transom and the other surfaces.  No wonder so many boats don't seem smooth in handling.  I am sure I am not alone in wondering about this.  Thanks a lot, ronny jetmore  p.s. you helped me a lot on my last questions, thanks.


What you are describing is very true, the rear of a Hydrostream is not necessarily true to the pad. I do it this way and have had excellent results: I measure and find the center of the top of the transom. Then I find the center of the pad only. On a Viper this takes some creativeness because of the concave pad. After finding both centers I draw a line to connect them. Now I have a vertical line on the transom. If this line is not 90 degrees to the top of the transom then you have the typical boat. I would then would use a carpenter's square and make a line vertically to match the pad centerline. This may not be centered on the transom but it is centered on the running surface. 

Hope this makes sense and gets your motor straight. As far as the bolt pattern, we use a template that has to be 20 years old. You could make a cardboard one for your use. 




Please submit whatever questions you have to  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.

Mark C.


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