older 85 hp evinrude

[assassins42]

I have an older 85hp motor when i start it it idles fine. take it up lake on plane then let off it will die will not idle at all nor will it start back up until it sits for little bit. but noticed tonight that if i take the hood off it runs and idles fine. to me it acts like it is not getting air and when i put the hood on it smoothers out any help is appreciated.

 

[schematic]

Re: older 85 hp evinrude

check for spark when it dies. If you have spark, look next for an exhaust leak....

 

[emdsapmgr]

Re: older 85 hp evinrude

Possible the engine is losing spark. Weak ingition components tend to fail once the engine heats up to normal operating temps. Possible when your cowling is off, the engine runs cooler. When the engine starts to act up you can perform two spark tests: start the engine. Warm it up. 1. with a set of insulated pliers, pull one spark plug wire off one plug. The engine rpm's should go down. Replace plugwire and go on to wire #2, etc. All cyls should have a decrease in rpm's when each wire is temporarily disconnected. If you get no rpm drop, likely that plug is not firing. 2. You can check for spark with an inductive timing light on each plugwire. The flashes in the gun will show misfires, no fires, and weak firing.