1984 305 Mercruiser won't start

Joined
Sep 9, 2002
Messages
21
Went to start up boat for the season and it wants to start, but it won't and then it just turns over after awhhile and won't even chug, or pop, or anything just crank and crank. It is a 1984 Glastron with a 305 Mercruiser. It has new cap, rotor, wires, some purple wire it needed. It has spark, but seems to get weak. Timing mark was jumping around and then disappearing. Put another brain box from a 4.3 and mark did not jump around, but still won't start. The coil is new and is putting out 12 volts. Rebuilt carb last year and it was fine for rest of season although it was doing this last year too and then we repaired enough and it finally started right up, but I don't think we ever really solved the problem. Timing chain maybe? Brain box? Any ideas. It's getting fuel. It should start. Have talked to two dealers(one who used to work on it) and no one has any ideas.
 
Joined
Sep 9, 2002
Messages
21
Re: 1984 305 Mercruiser won't start

Sorry it's an ignition amplifier(not brain box) and by the way pick up coil is new also.
 

crazy charlie

Vice Admiral
Joined
May 22, 2003
Messages
5,513
Re: 1984 305 Mercruiser won't start

start with something simple like the choke.Make sure shift interrupt swich is good.Charlie
 
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