1987 Cuddy Cruiser Alternator Issue - Thoughts?

[muskokamarc]

Hi everyone,

I've been having issues where my boat (1987 Sea Ray Cuddy Cruiser, Inboard 230HP 5.0L V8 Mercrusier) will die when out on the water, turn over when I try to start it, but wont start. I believe it's the alternator because when I get towed back in, and charge the batteries, it starts up fine.

I am relatively inexperienced with boat engines and engines in general... But would appreciate your opinion on where I can buy an OEM alternator, for how much (estimate) and if it's possible for me to install it myself (if you have any manuals or videos on this, please do send!). I'm located in Canada.

Appreciate your help!

Marc

 

[scoflaw]

Doubt it's your problem. What is it putting out for voltage ? Engine dies while running or hard to restart ?

 

[muskokamarc]

Doubt it's your problem. What is it putting out for voltage ? Engine dies while running or hard to restart ?

So here's what typically happens:

Charge both batteries before a ride.

Run the boat hard for a while, drop it to just above neutral basically, and it dies out. I can't recall for certain, but I think the voltage also drops from what would be considered normal, to low.

 

[scoflaw]

So you have 2 fully charged batteries of what age ? Does the engine spin over at a decent speed when it won't fire ? If so, it sounds more like the idle circuit in your carb. What's the voltage output when the engine is being run hard ?

 

[muskokamarc]

Batteries are brand new. Engine spins at same speed consistently, it just does't catch and start, if that makes sense...

Can't remember the exact voltage.

 

[scoflaw]

It's not your alternator then. How does it run when your running it hard ? Can you hit max RPM's. Have you changed your fuel filter, how old is your gas ? Does it ever idle fine ?

 

[muskokamarc]

Hit's max RPM's no problem. Cannot recall when I changed my fuel filter. I probably had half a tank of old gas and added another half of fresh gas. Only ever used premium if that matters.

Idling is always normal when I start it.

 

[Espos4]

If it cranks strong but doesn't start, I'd say the alternator is most likely not the problem.

Also, you NEED a digital volt meter that you can test battery voltage with and provide some information to yourself (and us). If its showing 13-14 volts consistently when running, and stalls at that point, you need to know that.

If the voltage drops below 12 with the engine running, you need to know that.

When it cranks but doesn't start, do you smell fuel?
Is there spark present at the plugs? Are the plugs wet with fuel?

Heat could be affecting something causing the shut down. If so, The engine cools down while being towed back, and it starts when cool again.

Several possibilities here, give us some more info to better diagnose this.

 

[muskokamarc]

If it cranks strong but doesn't start, I'd say the alternator is most likely not the problem.

Also, you NEED a digital volt meter that you can test battery voltage with and provide some information to yourself (and us). If its showing 13-14 volts consistently when running, and stalls at that point, you need to know that.

If the voltage drops below 12 with the engine running, you need to know that.

When it cranks but doesn't start, do you smell fuel?
Is there spark present at the plugs? Are the plugs wet with fuel?

Heat could be affecting something causing the shut down. If so, The engine cools down while being towed back, and it starts when cool again.

Several possibilities here, give us some more info to better diagnose this.

Thanks, I will try to give as much info as possible. Hard to test it now considering I know it will stall on me out on the lake, and don't really want to bother a neighbor to tow me back in.

I think it's lower voltage. The batteries are drained when I get back to the dock... Should've mentioned that...

I don't notice any fuel smell when it cranks. I don't think there was anything out of the normal in regards to this.

Not sure about the spark plugs being wet with fuel.

I thought that the engine was overheating as well, so I had the thermostat replaced, didn't make a difference.

 

[NorCal Boater]

Or you could skip all of this guessing and just take it to a service tech that knows boat circuits. He should have the proper test equipment and, from your description, of the problem know where to look. Ask your boating friends who they use and trust.

Yes, it might cost a few extra toonies but you're losing quality boating time by screwing around with it, guessing and doing the back and forth with us. Just MHO....
Shawn

 

[scoflaw]

You can do most testing at the dock. If its overheating start with the pump. Charge up your batteries and disconnect your alternator, see if it still discharges. You need to find where the voltage draw is coming from. Really need to monitor your volts and temps.

 

[Espos4]

Batteries are brand new. Engine spins at same speed consistently, it just does't catch and start, if that makes sense...

If the batteries are "drained" You should see a slow cranking speed or just a clicking when trying to restart the engine.

You statement above is a bit contradictory.

 

[muskokamarc]

Or you could skip all of this guessing and just take it to a service tech that knows boat circuits. He should have the proper test equipment and, from your description, of the problem know where to look. Ask your boating friends who they use and trust.

Yes, it might cost a few extra toonies but you're losing quality boating time by screwing around with it, guessing and doing the back and forth with us. Just MHO....
Shawn

I agree, trying to see if I can diagnose it before hand. Not in a rush to be honest.

 

[muskokamarc]

You can do most testing at the dock. If its overheating start with the pump. Charge up your batteries and disconnect your alternator, see if it still discharges. You need to find where the voltage draw is coming from. Really need to monitor your volts and temps.

I think this is a good idea. I may do this when I have a chance.

 

[muskokamarc]

If the batteries are "drained" You should see a slow cranking speed or just a clicking when trying to restart the engine.

You statement above is a bit contradictory.

Yea, that's true... Probably not the case then.

 

[muskokamarc]

So I've yet to take the boat out again since this issue, but I'm leaning towards taking it to the local marina and tellin them to just get it running.

Another observation that might help to diagnose this issue though... When I got stuck out at the lake, my neighbour attached cables from his boat to mine and we still could not get it started. It was turning over fine, but not starting.

 

[jdr999]

I had a crazy problem as well with my 260. I thought it was fuel related as I'd stall out after 15-20 minutes and would not be able to restart again.

It turned out to be a bad exhaust elbow which was over-heating my thunderbolt ignition. I had both replaced and all seems well again.

 

[JVM225]

Sounds like it could be an ignition issue. Something isn’t working when it gets hot, but will work when it cools down.
You are probably draining the batteries trying to start it again.
Had a similar problem on my old boat years ago. Swapped the thunderbolt Ignition module from the problem motor to the good motor and the problem moved with it so I knew the module itself was bad.
But that isn’t an option for you with just the one motor.
It could be what jdr999 described that is causing the module to overheat but if the boat isn’t overheating or you can put your hand on that riser while the motor is running it’s likely not the problem.
There should be Insulators (spacers) between the module and the riser holding the module a bit away from the riser anyway. Are they there?
Unfortunately, I don’t know of any way to test the module itself other than just trying it on another motor or swapping it for a new one.
There is a replacement module for the original brick type that comes with a new harness to adapt if you search around in the internet but they aren’t cheap.
I wouldn’t buy one unless you know that’s your problem.
You may get lucky and your Marine tech might have one he could try.
Or, the next time it happens just throw the hook out, relax and wait about an hour to let it cool down before trying to start the motor again
If your boat is overheating though and that is causing the module to shut down when hot then you need to deal with the overheating.
That’s a whole other issue.
Did the guy who replaced your thermostat make sure the cooling system was working properly after he finished the job?
Do you have a working temp gauge in your dash?
Is there an overheat/low oil pressure alarm on your boat?
Those are two things you should never leave the dock without.
When was the last time you had the water pump in the drive changed?
How old is your manifold and risers?
Is your circulator pump working properly?

 

[muskokamarc]

Sounds like it could be an ignition issue. Something isn’t working when it gets hot, but will work when it cools down.
You are probably draining the batteries trying to start it again.
Had a similar problem on my old boat years ago. Swapped the thunderbolt Ignition module from the problem motor to the good motor and the problem moved with it so I knew the module itself was bad.
But that isn’t an option for you with just the one motor.
It could be what jdr999 described that is causing the module to overheat but if the boat isn’t overheating or you can put your hand on that riser while the motor is running it’s likely not the problem.
There should be Insulators (spacers) between the module and the riser holding the module a bit away from the riser anyway. Are they there?
Unfortunately, I don’t know of any way to test the module itself other than just trying it on another motor or swapping it for a new one.
There is a replacement module for the original brick type that comes with a new harness to adapt if you search around in the internet but they aren’t cheap.
I wouldn’t buy one unless you know that’s your problem.
You may get lucky and your Marine tech might have one he could try.
Or, the next time it happens just throw the hook out, relax and wait about an hour to let it cool down before trying to start the motor again
If your boat is overheating though and that is causing the module to shut down when hot then you need to deal with the overheating.
That’s a whole other issue.
Did the guy who replaced your thermostat make sure the cooling system was working properly after he finished the job?
Do you have a working temp gauge in your dash?
Is there an overheat/low oil pressure alarm on your boat?
Those are two things you should never leave the dock without.
When was the last time you had the water pump in the drive changed?
How old is your manifold and risers?
Is your circulator pump working properly?

Thanks for all this info. I’m going to do as much investigating as I can.

Turns out my battery is a 2012, could that be the problem if it’s old?

I have changed it up with a new Noco Genius charger, maybe I’ll try it out.

 

[jdr999]

If the starter has enough power to turn over the motor without bogging down it's probably something else like spark.

If you have dual batteries try starting in ALL. That will give you the most power to the starter.