Fuse block question (Just wanting to make sure...)

When I look at the fuse block, I saw that I still have 3 or 4 unused spots. For both items, the positive wire, I believe, simply connects to the male connector and above each of these connectors there is a palce to insert the proper amp fuse (2A for fishfinder and 10A for stereo). The part I am not sure is the ground wire.

I saw a bunch of yellow (ground??) cables all linked to a part of the block with no fuses around. Is this sub-block a ground box? Is is where I need to connect the ground (black) cable of the stereo as well as the ground cable of the fishfinder?

Thanks as usual for your help! Andre

I've heard over and over again that everything is the same on a 7.5 h.p. Johnson as on the 15 horse, except the carb. I also heard it's not even the carb, it's just the jets.

I have a 1980-ish 7.5 seahorse that just does not have the guts to pop my inflatable up on plane with two people and a full tank aboard. I added those wings, which do help, but still just need a little more.

Anybody actually done this carb or jets upgade, or at least seen it work? Every dock rat seems to have heard of it, but nobody's done it.

Failing that, any ideas on how to squeeze a bit more out of a two-stroke (short of going 100:1 on the mix)?

Thanks!

All you need to do is get the parts list for both outboards and compare the lists. All the answers come to those that do the most homework.

-W

<4ever@usa.com> wrote in message

<4ever@usa.com> wrote in message

Changing just the jets in the carburetor is not rocket science but it is tricky - and you can end up with a useless carburetor if you make a mistake. Instead, why not try installing a used carb from a 15hp motor (larger jets and as you claim identical parts otherwise), seeing what happens, and if you don't like the results, switching back to the appropriate, original size. I wouldn't be too optimistic though.

The reason I don't think it would work is that horsepower is a function of the amount of gasoline converted "efficiently" into smoke. It is the pressure from the smoke that drives the pistons during the power stroke. There is a physical limit to how much fuel a cylinder of a given size can burn properly. Adding more than that would result in incomplete combustion in the cylinder, fouled plugs, back firing and higher exhaust manifold temperatures.

While it may be possible to increase the performance of your engine slightly by using slightly larger jets then what are currently installed (but perhaps not ones spec'd for twice the rated horsepower) my guess is that you would also need to somehow adjust the timing as well as the air entering the carob manifold, to maintain the proper air/gas ratio.

You could possibly achieve this by adding a blower (turbo) type arrangement and adjusting the dwell, but I think we've now strayed in way more effort than you had originally hoped for.

Oh, BTW, one side effect of "peaking" your engine performance, generally, is reduced engine life. So what you gain in additional hp tends to add stress and strain not originally intended for that hardware.

Hope this helps.

Cheers,

Robb

4ever@usa.com wrote:

Steve

Rob