Mercruiser 3/LX Inboard -Starting problem

SpringVelocity

SpringVelocity

Crew Member
Both my mechanics are tied up for 3-4 weeks so I am trying to do this myself. Boat died at 3900rpm after 15 minutes enroute. When it dies it misfired a bunch or times and then just quit and would not restart.

Motor just had a new ignition module put in. and done 5 trips no issues. So far:


1. Tach disconnected
2. Power to Coil
3. Power to Ignition module
4. Have Fuel.
5. Compression good across all cylinders.
6. Shift cable OK.
7. Spark at Coil.
8. Spark at Distributor.

Any ideas are greatly appreciated..
 
9. Kill switch set to 'run'? :p

You say you have fuel but is the fuel getting down the line to where it needs to go? Can you drain the carb (is there a carb?) and if so leave the screw out then pump a bunch of fresh gas in, let it drain out so you can see your getting fuel in there before putting the screw back in.

Every time my boat won't start or quits its a fuel problem. I've had to replace two of the female connectors this season any slight damage and they won't work.
 
What is the condition of your ballast resistor, you can bypass the resistor and see if it starts. Just tape the 2 connectors on it together or make a jumper wire. The ballast resistor is designed to reduce voltage to your coil once the engine warms up. Cold they allow 12v to coil, warm they reduce to 8-10v. That said your coil may have an internal resistor that I am unsure of how to test, or you could have a resistor wire built into the wiring harness. What is the color of the spark at your plugs? Blue or yellow?

When it was running did you notice strong fumes from your exhaust. I had a coil fail and that was one thing I noticed before hand.
 
Okay...so you have fuel. Have you looked down the carb while opening the throttle to confirm the jets are shooting fuel into the carb?
Do you have spark at the spark plug?
 
Thanks I will check in these comments this motor doesn't have points it has the electronic module that controls everything. So I think the ones without points don't have a ballast resistor. I think its incorporated in the coil.... I looked couldn't find one... And yes fuel is shooting into carb.

No when it quit no strong fumes.... Just backfired repeatedly lost power and died.

I have a coil ordered anyway just in case.
 
Found it when I was in emergency last month for our fishing event a local mechanic replaced the module in ignition. Unfortunately we think the rotor was not put on properly when it was re-installed..

So what happened is it wasn't fully clicked in and seated it its spun and then arced.. It burnt out the metal spring mechanism in center ...With no contact..... So it just screwed everything up. Also it melted the contact mechanism on the distributor cap. I am glad it happened as I learned a lot diagnosing it and now know what to look for. Even learned how to time the engine properly.

Unfortunately I jumped the gun with getting a coil and module, but now have them as spares.
 
SpringVelocity said:
Found it when I was in emergency last month for our fishing event a local mechanic replaced the module in ignition. Unfortunately we think the rotor was not put on properly when it was re-installed..

So what happened is it wasn't fully clicked in and seated it its spun and then arced.. It burnt out the metal spring mechanism in center ...With no contact..... So it just screwed everything up. Also it melted the contact mechanism on the distributor cap. I am glad it happened as I learned a lot diagnosing it and now know what to look for. Even learned how to time the engine properly.

Unfortunately I jumped the gun with getting a coil and module, but now have them as spares.
Click to expand...

Glad you found your problem but more importantly you took another hard step to being a semi-competent backyard mechanic. You'll save uncounted dollars over the years and have a lot more confidence in your engine if you know it well. My 2 cents!!LOL
 
Perfect, glad you found out the problem. I hope it runs great for you from here on in....they are great motors!
 
You must log in or register to reply here.

Similar threads

OceanCable
Trade: Chev 358 for 70-90 hp Yamaha 2-stroke (or comparable)
Replies
2
Views
727
OceanCable
OceanCable
Back
Top