Wont start

[Ken Sabin]

OK, help me diagnose this...................



I have Merc 9.9 4 stroke.



Running at WOT for about 6 minutes or so. Running like that, for that long is normal. I shut it off, tie up, go get the truck, trailer backed down. Jump back in boat-Wont start. Cranks fine, wont fire. Kill switch and throttle both in right position. Nothing ! Go figure.



Any ideas where to start looking?? Thanks

 

[Bob Bourget2]

Did you prime the bulb?

 

[Ken Sabin]

yes

 

[Jim in VA]

Vapor lock? Does this happen only when the engine is cold, run for 6 minutes then shut off? Or does it happen even after the engine is warmed up well? Seems you have some type of fuel flow interruption.

 

[Ken Sabin]

I agree Jim, I think its fuel related.



After priming, cranking, etc I pulled the plugs, thinking they may be fouled. Clean as a whistle. Almost too clean, they were also dry as a bone. With all that cranking and throttle pumping, id have thought they'd be wet with gasoline... Also, after all that cranking, I smelled no gasoline fumes on or around the motor.

 

[Bob Bourget2]

Remove the fuel line from the carb and pump the bulb.....see if fuel is making it that far. If it isn't check for obstruction from there to your tank. If it is......and it still doesn't start, try spraying a bit of "carb cleaner" through the intake while you are cranking it. If you are getting spark, it should give you some sign of wanting to start. If it doesn't, remove plugs again, ground them to the block and pull it over a few times. You should see spark. If you do...and the fuel is making it to the carb, try removing the bottom drain screw on the carb, priming it a few times to purge the system, clean up the fuel, re-install the plug and have another go at it. If it still doesn't start, {but will run on the carb spray}, remove the carb, take it apart and clean it. There may be an obstruction in the needle / seat.

 

[firedog978]

Is it possible that you have the fuel bulb in the wrong direction? The arrow should be going toward motor.