Outboard won't start

Question

I have a 17 foot boat with a 150 horse mercury black max outboard. It has always started well. Now it cranks but wont turn over. Seems like a fuel issue but i have no idea. charged the battery and the voltmeter is reading fine. Sounds like it should turn over. Plenty of oil in the reservoir. Put gas in fairly recently. I had a fuel line leak recently and I changed it out, maybe it is not holding fuel pressure. Thanks for any tips

Answer 1

premix fuel in a spray bottle instead of starter fluid or carb cleaner, for reasons mentioned above.

Fuel line pressure, you can tell by whether the primer bulb is firm.  If the bulb doesn't get firm when you pump it up, it's either leaking air somewhere, or fuel.  Closely inspect all fuel lines under the cowl while pumping the bulb.  Engine off, tilt the motor full up and squeeze the primer bulb -- if gas comes out the carb throats, your float valve needles/seats are worn or sticking and flooding the engine.  Carb rebuild will fix that.

Check for spark:  remove a spark plug, reattach it to the boot, hold it against the engine block and look for a spark while somebody turns the engine over with the key.  Use a plastic or insulated tool to avoid a nasty shock.

Check all six...if you get no spark on some or all cylinders post a question about how to troubleshoot your ignition.  Don't forget to say what year the motor is.

If the plugs are dry after cranking, that generally indicates fuel starvation.

You don't say what year your motor is;  if it has choke plates, make sure they're all closing off completely when the choke is engaged.  If it has the primer/enrichener system instead, make sure the solenoid actuates when you engage the choke button, and make sure that it's draining fuel into the engine.

Cranking RPM's -- needs at least 250 RPM to generate spark.

Answer 2

NEVER put carb cleaner in a 2 stroke engine's carb to clean it.  That is the equivilent of taking all the oil mixed in with the gas in the carb and destroying it.  No 2 cycle oil in gas means no lubrication, and that equals expensive damage.

If you must do a carb cleaning, you must disassemble, clean and soak the metal parts with carb cleaner, let it sit overnight, then inspect and dry all potential areas where carb cleaner might still be in it.  Then reassemble correctly and see if it will run.

Answer 3

It can only be one of two things... Fuel/delivery or fire...

Hit the carb directly with carb cleaner spray and try to start, if it sputters or even starts for a  moment, then your not getting fuel to the carb.... If nothing different happens then it's a fire issue... likely a coil or magneto...  

Answer 4

Have you checked  the spark plugs for corrosion and such other evidence of bad shape?

Answer 5

If you think it is not getting fuel give it a prime put a very small amount of fuel in the carb and if it fire you are correct.

Could be the anti-siphen valve on the tank