More OOmph!

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farmboat

Cadet
Joined
Nov 15, 2001
Messages
9
I have a 1974 Evinrude 115. It runs well, but I want to play with the power. What's a bolt-on that will up the power--heads, carbs, what?<br /><br />Grampa the Big John :D
 
12Footer

12Footer

Fleet Admiral
Joined
Mar 25, 2001
Messages
8,217
Re: More OOmph!

Boyesen Composite Reed set. They don't last long (as with many HP parts), but the extra HP will blow your mind. It's also one of the easiest to do, and easy to go back stock from.<br />
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Terry H

Lieutenant Commander
Joined
Sep 25, 2001
Messages
1,862
Re: More OOmph!

On a related topic...I have a 120 Looper that really wants to be a 140hp motor. 120TLESB. Are there anything I can do? :cool:
 
JB

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: More OOmph!

Ahoy, Grampa. Hopping up outboards just for fun is counterproductive most of the time, and the OMC 115 is the highest development of that block.<br /><br />Try bolting on a bigger block. . .125, 130, 135.<br /><br />Using carbs and reed plates from one of the bigger engines might help a little, but would probably cost more than your engine is worth.<br /><br />Red sky at night. . .<br />JB :)
 
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Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: More OOmph!

Both the V4 cross flow and the looper are great motors. Before you try anything, define where you are now. You will be amazed how much you can get out of a stock powerhead if it's set up correctly.<br /><br />Let me know your set up including RPM at WOT, water pressure, type of boat, type propeller and top speed now. Then define what you are looking for. Better holeshot, more mid range or pure top speed.<br /><br />Just for reference, my V4 cf ran 76 on my 15 Allison and my V4 looper ran 82. Both powerheads were stock and set up for drag racing. Way too much fun!<br /><br />Good luck!
 
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Terry H

Lieutenant Commander
Joined
Sep 25, 2001
Messages
1,862
Re: More OOmph!

Dhadley...I am set up with a jet pump on a 17' aluminum river boat...don't have a tach so don't know wot rpms. Motor runs nicely, but the boat can handle more power, but is weight sensitive (otherwise I would just buy a bigger motor). Top speed in still water is about 40mph gps, which is fine, but with jet pumps hole shot is lacking. Sometimes you need to get on plane faster in some of these wild rivers we have out west...that is what I am looking for...Thought100
 
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Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: More OOmph!

A jet is a little different but we still need to know the RPM's. Still a great motor.<br /><br />Good luck!
 
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Terry H

Lieutenant Commander
Joined
Sep 25, 2001
Messages
1,862
Re: More OOmph!

Dhadley...fortunately I installed a tach yesterday so hopefully I will find enough water in the Snake River to get her opened up all the way tomorrow. The motor came off a ships landing craft and saw little use, but was maintained well, has les than 100 hrs run time. As far as I can tell there are not modifications other than upkeep. I unhooked vro and mix the fuel. this motor has much better holeshot and top end than the 140 crossflow it replaced. More is better...Thought101
 
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Terry H

Lieutenant Commander
Joined
Sep 25, 2001
Messages
1,862
Re: More OOmph!

Dhadley...Had her out on a glassy lake today...wot rpm come out to 4700. Can't get any more. Runs and starts good...would be like using too much prop. Don't have much choice in jet pump impellers. Any ideas to get a little more power?
 
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