Engine Dies Only After Cruising for Over an Hour

[Crownline290]

New to the forum. I have a 2003 Crownline 290, twin Mercruiser 5.0 engines with TKS carbs.

Boat runs perfect, but sometimes when I cruise for more than an hour, the starboard engine dies as if the key was turned off. Sometimes it will restart right away, other times it has to sit for at least an hour before it will restart. When the engine won't start if I push the throttle fully down it will rev all the way up and then die again.

The problem is intermittent and driving me crazy.

So far, replaced the coil -- no change. Next, I'm thinking the ignition switch and fuel pump.

Desperate for some help.

 

[dubs283]

So far, replaced the coil -- no change.

no surprise

if this is a thunderbolt ignition check the sensor in the distributor. if it's not the latest fully potted three wire one, replace it with a genuine quicksilver brand one

 

[Crownline290]

Thanks. I will check this tonight.

 

[Scott Danforth]

its never the coil.

does it slowly die, or just cut out

if it slowly dies, look at your fuel system. specifically the vent line

if it just cuts out, follow the TB ignition troubleshooting in the stickies at the top of the forum. most likely you will need to replace the trigger in the distributor with the new upgraded 3-wire

 

[Crownline290]

It doesn't slowly die, it just cuts out like the key was shut off. I'll following the TB ignition troubleshooting and report back. So far, you guys have been extremely helpful!!

 

[Crownline290]

Ok, so I replaced the ignition sensor with the upgraded three wire sensor. Interestingly enough, the engine already had a three wire sensor. The label on the old senor indicated that it passed inspection in August 2016. Clearly the sensor was replaced once before I purchased the boat.

Is it possible that the three wire sensor would go bad? Or is there another issue that I’m having?

I replaced the sensor anyway, but haven’t had a chance to take the boat out on a long ride to see if the problem has resolved.

 

[Rick Stephens]

Is it possible that the three wire sensor would go bad? Or is there another issue that I’m having?

I replaced the sensor anyway, but haven’t had a chance to take the boat out on a long ride to see if the problem has resolved.

How is anyone to answer that? Of course it is possible, virtually anything is. You can just have a faulty lanyard switch, or a corroded power connection at the Thunderbolt module.

 

[Crownline290]

Thanks. If I still have the issue, I’ll check that next.