Mercruiser dies after getting on temp

YOBE said:

Hi,

Did my first test run on the water today. Engine (mercruiser 165 6 inline from late 70') started fine. After driving in the water for about 10-15min (slow speed) and when the engine was on temperature it suddenly died.
After waiting for about 15-30sec I could start it again but runs for about 5 seconds and then dies again. Even if I throttle up a bit.
Thought it was missing fuel but that is not the case.
Feels like the heating up of the engine is related to this as in the first moments when it was cold it did run smooth.
Carb is cleaned.

I read that the coil could be bad. Does this make sense?
Other suggestions?

Thanks

Click to expand...

YOBE said:

This is whats happening
View attachment 410272

Click to expand...

alldodge said:

Very rare to be the coil

Did you do maintenance on your points, gap 16*, dwell at 31*-34*?

How old is the condenser?

Click to expand...

kenny nunez said:

Before starting the engine connect a volt meter to the +side of the coil. Set it up so that it stays connected and run the engine until it stops, the voltage should not go below 8-9 volts. If it does go down then the resistor wire is the problem. Sometimes the rotor will go to ground when the engine heats up. Try another rotor when it stops to see if it continues to run.
A non American made condenser can also cause your problem.

Click to expand...

YOBE said:

Hi, thanks for the input. But what rotor do you refer to?

Click to expand...

Scott06 said:

when it dies are you missing spark or gas ?
if you dump a little gas down carb can you keep it running ?

do you loose spark - put timing light on coil wire see if its dropping off.

On a points system there will be two paths supplying power to + side of coil- one is typically supplied off starter for full 12 v during cranking, other goes through a ballast resistor or resistor wire when key is in run and should supply 9 v when in run. Seems like you might be loosing voltage to + side of coil when in run position

Click to expand...

YOBE said:

I dont know the age of the condenser. Bought the boat second hand.
For the dwell I need to find out how I can do this.
Can this be linked to the issue I am having?

Click to expand...

alldodge said:

The rotor Kenny mentions is the one under the distributor cap, it's also where you will find the points and condenser

Points and condenser are cheap and a new to you boat should install a new set. Need a set of feeler gauges and watch a you tube vid for any motor to see how to do it, doesn't have to be marine

Once adjusted need to check/set timing

Click to expand...

YOBE said:

I have seen online that people invest in an electronic setup. Is it worthwhile you think?

Click to expand...