98 Mercruser HELP!!!!

[Reel-Oars]

Need to pick y'alls brains on an inborad question. The motor is a 98 Mercruser 4.3. The problem, when the boat starts to turn over we loose spark (checked with spark gauge). Two sparks on the gauge then nothing. We replaced the distributor, Plugs (gapped correctly), wires and battery. Checked the ignation switch with a meter which turned out fine. Starter engaged like normal. All connections are tight. I'm clueless from here. Anybody have an idea?

Thanks for help,

Jason

[Avenger]

Gasoline engines are not my area of expertise, but it sounds like the coil may be losing voltage when the engine is cranking. Can you measure voltage at the coil connections to make sure you've got 12V there while the starter is engaged?

[selectlines]

if your starter is fine I dont have a clue..... But every year we have to replace the starter on our 4.3 no matter what, don't know why but it always works just fine after that.

[seapower]

Loose spark after 2 revolution's and then the spark quit's, while the engine is still turning over, or does the starter stop as-well? Sorry but your explaination wasn't clear enough for me. Frank

[ShaneS]

check your battery. some mercruisers will loose spark if the battery voltage drops. motor will turn over but will not start.

[ripple]

make sure u have 12v at the coil when the ign key is in the on position if not put 12v directll to the positive side of the coil(purple wire on side of coil)...if it starts and runs chec the oil pressure sender on left side rear of block .....when the sensor senses oil pressure it allows 12v to coil ....this could be ur problem not sure if ur eng is set up like this but if u give me serial # i can help more