'93 Evinrude 90 Losing Power

[BillyGA]

My VE90MLETS cranks and idles normally. However, when I take off and get on plane the engine loses power and seems to be "missing" after approximately 15 seconds. I back off of the throttle and come to an idle for 15 or so seconds then take off again. The engine seems to have full power but loses it after 15 or so seconds. I am again able to bring her to idle, take off, and then lose power. This process seems to be able to be repeated in the same manner as much as needed to get back to the boat dock. The oil tank has plenty of oil in it. I think the amount of "blue smoke" coming from the exhaust at idle is normal to indicate the engine is getting oil. Important to note: The tachometer indication has been intermittent for 10 years now. It might work fine for 10 minutes, stop working for five minutes, bounce around a minute or two, etc. A mechanic told me years ago some electrical part (don't remember what part) might be going bad and may eventually have to be replaced. Any ideas?

 

[oldboat1]

Rectifier/regulator would affect tach operation. Water cooled unit that could overheat, presumably affecting operation. The power pack may also be the culprit.

Is there any history of overheating?

 

[BillyGA]

Thanks for the quick reply. No history of overheating. Steady stream of water coming from the "pisser." Could the rectifier/regulator cause the engine to lose power at WOT but run fine at idle?

 

[oldboat1]

more likely the power pack. You might hook up a timing gun to plug wires to see if there is fire at speeds. Place the gun where you can see the light or have a helper with you -- no flash means no juice to that plug.

 

[racerone]

Agreed test run with timing light one cylinder at a time.----Observe the light.----And the steady stream coming from the tell tale indicates that water pump is working.-----But that does NOT indicate that motor is cooling properly !!