‘76 Merc 1150 “tower of power” starts then instantly dies

[nico_mcgee]

Hi all, I’ve been struggling with this 1976 1150 for some time now. Father in laws boat, stores outside. We always have trouble starting it first time of the year, but this time it wouldn’t start at all. Turns out water had gotten in to the fuel. Took all three carbs off, cleaned well and reassembled and installed. Plugs pulled, sea foam sprayed into each cylinder. With idle control wide open the motor will fire, but it dies within 2 seconds, squeezing primer during start makes no difference (possible fuel pump issues?), all six plugs have good spark. Static timing setup was done 5 and 21 degrees respectively. I can’t think of any reason the motor won’t run for more than a couple of seconds? I do note that the plugs seem oddly dry based on all the fuel dripping out of the carbs after primer bulb pumping and engine attempting to start. Choke makes no difference, and this motor has no enricher that I know of.

could it be related to reed valves sticking?

thanks in advance for any thoughts you might have!

 

[Chris1956]

Probably not a reed valve issue. Probably a choke issue. Spray some 50::1 mixed fuel into the carbs and close the choke plates with the manual choke. If that doesn't start it, maybe trigger is intermittent or wiring harness is shorting?