How Much Difference Will 15lbs make?

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FilthyPlumber

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I currently have a 75 Johnson 9.9 2 stroke on a 12' 60's Riveted Valco. My current engine is roughly 69lbs and am looking for a newer engine. The Mercury 4 stroke I've looked at is 84lbs. How much of a difference will the extra 15lbs make on the back of the boat? I'd prefer one of the newer 2 strokes with electric start but can not find anything on the websites about selling them. All I can find for sale is 4 strokes.
 
Take your anchor out of the front and put it in the back and go for a boat ride. Let us know how it goes.


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I went from a mid 80s 15 hp two stroke to a 2008 20hp 4stroke. It added 20# or so to the transom. But I was able to go from a 6 gal to a 3 gal fuel tank because the 4 stroke goes twice as far on a gal of fuel! So saving the weight of the fuel I broke even overall. (Fuel @ 6.2 # per gal plus’s the difference between a 6 gal and 3 gal tank)


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FilthyPlumber said:
I currently have a 75 Johnson 9.9 2 stroke on a 12' 60's Riveted Valco. My current engine is roughly 69lbs and am looking for a newer engine. The Mercury 4 stroke I've looked at is 84lbs. How much of a difference will the extra 15lbs make on the back of the boat? I'd prefer one of the newer 2 strokes with electric start but can not find anything on the websites about selling them. All I can find for sale is 4 strokes.

Probably won't make one bit of difference.

What size is your fuel tank which is probably in the back of the boat?

Gas weighs abut 6lbs per gallon. Does your boat act differently with a near empty tank then it does with a full one?
 
I have a 3 gal tank so id keep that the same. Not much difference if it's even noticeable when the tanks empty vs full. I keep a battery on board for my trolling motor so I don't have to row as far if my motor starts having issues so I'd just use that for the electric start since it's already there.

I was thinking about putting a small piece of plywood in the bow to make a level service to mount the gas tank and battery on when I'm by myself to keep it down a little more. Any reasons not to do so? Would the longer fuel line and battery cables be an issue?

Now that I think about it, the only thing the extra weight would change is how much weight of gear and passengers I can bring in board.
 
FilthyPlumber said:
I have a 3 gal tank so id keep that the same. Not much difference if it's even noticeable when the tanks empty vs full. I keep a battery on board for my trolling motor so I don't have to row as far if my motor starts having issues so I'd just use that for the electric start since it's already there.

I was thinking about putting a small piece of plywood in the bow to make a level service to mount the gas tank and battery on when I'm by myself to keep it down a little more. Any reasons not to do so? Would the longer fuel line and battery cables be an issue?

Now that I think about it, the only thing the extra weight would change is how much weight of gear and passengers I can bring in board.

I had a 14' Discovery Marine V-hull with a 9.9 Yamaha. With just me it was a rocket ship. Add one passenger and it was a tug boat.
 
FilthyPlumber said:
I have a 3 gal tank so id keep that the same. Not much difference if it's even noticeable when the tanks empty vs full. I keep a battery on board for my trolling motor so I don't have to row as far if my motor starts having issues so I'd just use that for the electric start since it's already there.

I was thinking about putting a small piece of plywood in the bow to make a level service to mount the gas tank and battery on when I'm by myself to keep it down a little more. Any reasons not to do so? Would the longer fuel line and battery cables be an issue?

Now that I think about it, the only thing the extra weight would change is how much weight of gear and passengers I can bring in board.

First off you are going from a 69# engine to an 84# engine or 15 more pounds. Not mentioned.... have to add a battery....more weight.
Second. if you do your plywood thing and mount the battery and fuel in the bow it will be in the way, you will have to run larger cable as well (more weight) and the boat's C/G will be raised not to mention it will be a pain to step over. Not good. Long fuel lines are always in the way as well.
A Valco is a pretty wide boat. Just duplicate the weight (add another 35-40#) and go run it. Move the weight around a bit to find a happy medium.
You have not mentioned using your trim positions on the engine. They come in handy with added load. Are you aware of them and their benefits?
 
I mentioned earlier that I currently keep a battery on board for my electric trolling motor in case I run out of gas or the motor cuts out on me.

I've never looked into the trim too much on aluminum boats. Growing up I never saw my uncle's or pops messing with it. Are you referring to the pin you can use to adjust the "angle of the dangle" so to speak?
 
Yes.
On a smaller boat it can make a world of difference when carrying different loads. It can help plane the boat quicker or make the boat run faster top end. Weight placement in a small boat is extremely important since it changes the overall center of gravity faster and more drastically than in a larger or longer hull.
Play with the pin placement and you will quickly get a feel for what I am talking about.
 

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