Upgrading Evinrude '94 6hp

Sullie

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Jun 5, 2004
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2
G'day I have a Evinrude 6hp 94model.<br /><br />It's a good reliable motor, but It just needs a little bit more power (our tinny can handle an 8hp easier, we just couldnt afford an 8hp at the time)<br /><br />anyway, the word around the campfire is that if you put a 8hp carby system on the 6hp, it will be the same as an 8hp model. has anyone done this or heard anything of this?<br /><br />- Adam.
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Upgrading Evinrude '94 6hp

G'Day Adam.<br /><br />Welcome to iboats. :) <br /><br />We hear those myths several times a week. It seems any family of engines that share displacement is the subject of such ideas. <br /><br />Engineers get different hp ratings by changing some of the factors that affect output (and the rpm at which the output peaks).<br /><br />Increased intake flow is of little value without altering port timing and exhaust flow to match.<br /><br />Changes in noticable boat performance are far more easily attained by fine tuning the boat, prop selection and rigging.<br /><br />Finally, the cost of "converting" a 6 to an 8 would be far more than the original difference in price.<br /><br />I think the thing to do is fine tune your rig and trade the 6 for an 8.<br /><br />Good luck. :)
 

Sullie

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Jun 5, 2004
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Re: Upgrading Evinrude '94 6hp

Yup, I just did some basic searching and found that out :( <br /><br />It's a shame because it just needs that little bit more hp since myself and my bro have gotten older & a bit heavier, hehe.<br /><br />I guess the only good thing to do now is start looking for that "perfect buy" again.<br /><br />Adam.
 

Chinewalker

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Joined
Aug 19, 2001
Messages
8,902
Re: Upgrading Evinrude '94 6hp

The 8hp and 6hp share crankshaft, pistons and block, but the major difference lies in the intake side of things. The 8hp as an extra reed petal per cylinder (four vs. three) and the crankcase is cast differently to accomodate that...<br />- Scott
 
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