70 hp evinrude bogs down...please help

[mbooher]

my 70 hp evinrude works fine out of the water.when put in the water it idles fine but shuts off when put into forward or reverse.the carbs have been cleaned , fuel lines replaced and new spark plugs. but same problem. wondering why the motor conks out when put into forward or reverse when under load...Please help? 1985 model

 

[JB]

Re: 70 hp evinrude bogs down...please help

Howdy, MBooher.<br /><br />You are probably not running on all three cylinders. The first thing to do is find out which, if any, are dead. Then find out why.<br /><br />First, disable each cylinder while the engine is running. Pull or short out the plug. Any cylinder that causes no drop in idle speed is dead.<br /><br />Next. Confirm that there is a hot blue spark to each cylinder.<br /><br />Next, Confirm that each cylinder is compressing over 100psi and that there is less than 15psi difference among them.<br /><br />Squirt some fuel mix into any cylinders that are dead while the engine idles. Does the speed pick up?<br /><br />Get a service manual for your engine, then let us know what you have found.<br /><br />Good luck.