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Can you use a boat ramp as a test tank?

Klink

Regular Contributor
I used the Joe Reeves WOT spark advance setting method on my 115hp Johnson. I did the same on a 25hp, but in that case because the boat only went 24mph at WOT, I could "safely" also check it on the water running at 24mph. I found that the spark advance was off the target and I adjusted it accordingly. I'd like to test a 70hp and my 115hp on the water, but they go too fast at WOT.

I saw some boat yard test tank videos on YouTube and it just looks like they made a boat ramp and back the trailer into it. Can I just back my trailer into a boat ramp and do a WOT test to verify the spark advance is OK? If I strap the boat onto the trailer and leave it hitched to the truck, will the boat thrust break the trailer winch post and hit the truck or something? I look at the videos and do not see much thrust/push forward on the trailer and they are running even big twin engines.
 
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Find someone else to drive the boat. Your prop could also wash out material at the landing and could cause issues for someone else
 
You might not get caught or worse, but that practice is destructive to boat ramps. What if everybody did it? If nothing else. tie it up securely to the pier. And hope it doesn't pull your cleats off the boat.

Seriously, the right way is use a test prop. Yes, they are expensive, and yes that is why the shop charges to do the job.
 
You can take a damaged prop, cut the blades off equally and make a test wheel out of it and use it at the dock. OMC used to have specs on what to cut off for the HP mtr you had.
 
No big deal, I am satisfied with the results I got with the Joe Reeves method on the 115hp, and the 70hp should be fine, since it belongs to a friend who used it since it was new 25 years ago. I just was wondering about using a ramp.
 
Its a simple adjustment to do out on the water and normally never needs to be touched unless you messed with it. The throttle pickup adjustment needs to be checked/adjusted when you pull the carbs.
 
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