Merc 80 wont start

[Jafgoodguy]

Hello, I have a 1987 Merc 80 HP outboard. The motor will crank but will not start. I had the boat out last Saturday and took about a 40 min ride out to an island. I stayed for about 2hours and started the engine to get ready to leave. I had the engine idling waiting for my buddy to get his boat going. I started to motor out into the channel at slightly above idle speed and the motor stopped. I could not get it restarted and got towed back to the landing. So far I have checked compression which is 115-120 in each cylinder I am getting spark on all of the plugs and there is fuel in all of the carb bowls. I also checked output from the fuel pump and it is pumping plenty of fuel and the primer ball stays firm. I am stumped. anyone have any ideas?

 

[12Footer]

Re: Merc 80 wont start

This sounds like a tough one to diagnose long distance, but I do have some things you can try , that may narrow-down the range of posables a tad.<br />First, spray some WD40 directly into the carbs (about 3second burst in each), and crank it. It it sputters or runs briefly, it is fuel related, no question.<br /><br />Also, you state it has spark. Is it a bright blue spark,or very weak spark?<br />Try the WD40 test with new plugs just the same. They only cost 1.90 each at the auto parts store, and funky things happen to plugs.<br /><br />Also,being a Merc, check and see if this puppy has a timing belt (I know the '79 model does....And if so, it may have jumped a tooth, throwing the timing off the top of the stroke.<br /><br />Let me know what you find, and maybee we can narrow it down further.

 

[drpev150]

Re: Merc 80 wont start

I have a 1986 Evinrude V6 150 that did something similar. As it turns out, I had a vacuum leak between the carbs and the reed boxes (intake manifold). Granted the engine would restart after a a bit of priming and work, but it is something to check. I would start by making sure all the bolts around the carb are tight, AND make sure that the timing is correct.