74 'rude 15hp. No power at full throttle/dies idled

R

ru4iowa

Recruit
Joined
Jun 16, 2005
Messages
1
Bought this used boat, at first motor started readily, but didn't give much power when I put in gear and opened up the throttle. Put 2 new plugs and replaced all the gas, used carb cleaner.<br />Got to idle and ran good in a water tank. Took out to the lake, and the boat has about 1/3 power at full throttle. Also likes to die at idle. Can be tough to start too. Once it gets going, it will occassionally sound like it's winding up and wants to run faster, but then doesn't. Everyone says that the motor "sound's really good" but I just don't think somethings right with the rich/lean screw and/or the fuel pump.<br /><br />I'm a novice, I do have a repair manual from EBAY, and some limited mechanical assistance from a friend. <br /><br />Why can we adjust the rich/lean and get it screaming in the water tank (even in gear) and then at the lake it's a dog? (regardless of how I adjust the carb)?
 
X

Xcusme

Commander
Joined
Apr 21, 2003
Messages
2,888
Re: 74 'rude 15hp. No power at full throttle/dies idled

First off, Welcome to iboats!<br />A couple of things to look at, and consider.<br /><br />Spraying carb cleaner into the carb does basically squat. You have to remove the carb, disassemble and soak in carb cleaner, follow by blowing out all passages with compressed air. Replace gaskets, float (if cork) etc, and re-assemble (carb kit).<br />While running in the tank, pull/replace spark plug wires, one at a time. You should have a strong blue spark. If either wire, when pulled, has no effect on the RPM's of the motor, that cylinder is dead. You may be running on only one cylinder.<br />If you don't have spark to both plugs, it's time to pull the flywheel and have a look at the coils,points,condensers. It's a good idea to pull the flywheel anyway to get a general condition of the ignition. If this is a new to you motor, be sure to replace/inspect the water pump, and lower unit lube.
 
H

herters

Cadet
Joined
Jul 19, 2004
Messages
28
Re: 74 'rude 15hp. No power at full throttle/dies idled

While you are doing all the above replace the thermostat and clean out the water passages. You will not be sorry you spent the time or the money.
 
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