Engine dies

[cimy3]

I have a 1989 mercruiser 5.0L (200 HP) 305. cid alpha one drive with thunderbolt IV ignition system.

I was out on the lake today and as I as leaving the channel (first thing in am) the engine cut out...no hesistation, just plain died. OK...after 30 seconds started right back up first try...no problem, ran normally. Fished all morning with the kicker motor....time to quit fishing, so started the big engine and took off towards the channel...after couple minutes just died again. OK, wait 30 seconds, starts right back up and runs perfectly. Go to take off again and it shuts off again.

I was thinking that it must be the ignition coil....there is no hesitation, no sputtering, just dies. I had the carb rebuilt and a tuneup two years ago. Thoughts?

1st question: When the ignition coil overheats and shuts down...is it hot to touch? Mine is not.

2nd question: With the Thunderbolt IV ignition is there a special coil that I have to get.

Thanks for your help.

Ray

 

[cimy3]

Re: Engine dies

ttt

 

[Bt Doctur]

Re: Engine dies

have quite a few tests before you start throwing money.
check the main harness plug on the engine ,may just be a bit loose or corroded

 

[searay3]

Re: Engine dies

When it dies are you losing spark or fuel? That is the first question...check right after it dies...

 

[cimy3]

Re: Engine dies

Well, I brought the boat home, put it on the muffs last night....the engine did not cut out. OK, so I tried again today, again the engine did not cut out. (Each time it spent approx. 20 minutes running.

So, I checked all the battery cables...looked good.

Checked main wiring harness...looked good, except it had a zip tie on it...replaced with a hose clamp.

Checked for corrosion on plug from coil to distributor. There was a little on distributor plug...cleaned.

Guess I will see what happens at the lake tomorrow.

If it happens at the lake, how should I check the fuel/spark areas because it starts right back up....no hesitations, no extra cranks and no sputtering. Starts right up no problems.

Thanks. Ray