1990 evinrude 120hp wont stay running(vro)

[patric hunt]

i can start the motor and it will run briefly(about 1-2mins) then it will start coughing/sneezing white smoke from prop and out of carbs then die even while i adjust throttle. this all started after running tank almost out of gas before it ran great/all the time. i have replaced all fuel lines from tank/new water seperator, new diapghrams in vro(used as fuel pump only, i premix my fuel50:1), cleaned carbs(although they appeared clean), replaced all fuel lines in motor(after vro). New starter/solenoid/plugs. After the initial short start(1-2mins) it will not start/run again for more than a few seconds. HELP?

 

[yamamarinetech40]

Re: 1990 evinrude 120hp wont stay running(vro)

hmmm....people say 'white smoke' but that's not possible, it's either got a bluish grey color or it's steam....run a compression check first...if it is white it's steam...have you looked at plugs, we need to know what they look like, if you need someone to help you read plugs, do that....and how were the carbs cleaned EXACTLY?

 

[patric hunt]

Re: 1990 evinrude 120hp wont stay running(vro)

it must be steam because it appears white. the compression is between 110-120psi on all 4 cylinders. three plugs are wet/clean fuel the 4th spark plug is fouled up. the carb cleaning was just soaking in cleaner and blowing out with air compressor, but all appeared clean and could find no gunk visually or after wiping with cloth. am i wrong to assume i have a fuel problem since it ran great until almost running out of fuel?

 

[tashasdaddy]

Re: 1990 evinrude 120hp wont stay running(vro)

principle is the same for your motor. http://forums.iboats.com/showthread.php?t=244013 smoke out carbs, suggest you check the woodruff key on the flywheel, sound like it sheared, throwing timing off. if so the only fix is to replace the key. remove flywheel and check.

PULLING FLYWHEEL

you need a harmonic balancer puller, you need 3 - #8 harden bolts, that fit the 3 holes in your flywheel. standard hardware store bolts will strip out, causing more problems. loosen the flywheel nut, leaving it on so it protects the thread. thread the bolts in 7/16 of an inch. then tighten the puller, adjust so it has a straight pull. now tighten the puller, rap the center bolt with a hammer, then tighten some more. you may have to let it sit over nite, and repeat in the morning. this is a compression fitting, it will eventually POP!!. do not loose the woodruff key that goes in the groove of the flywheel and the crank shaft. then installing the flywheel, it has to be totally clean, no oil, woodruff key in place. then torque the nut to the specifications for your particular motor. if you do not do this, the woodruff key with shear, and you will be repeating these steps.

 

[ezeke]

Re: 1990 evinrude 120hp wont stay running(vro)

Sounds like it is only running as long as QuikStart has the timing advanced. Watch the advance when you start it and see if it backs off once the engine warms up a little.

You should not have anything smokelike blowing back through the carburetors. If you do, check the reeds.

 

[reeldutch]

Re: 1990 evinrude 120hp wont stay running(vro)

make sure you dont have a air leak or bad fuel pump.
rig a clear fuel hose before the carbs and run the motor check for air bubbles.

or hook up a fuel pressure gauge.