Unexpected Engine Shutdown

[Brian D]

Has anyone experienced any issues such as starting the engine and switching all accessories on the helm (e.g. blowers, lights, etc) and the engine shut off?

I think it may be the alternator or voltage regulator. I had just tightened the alternator belt when the issue occured. I had the engine doors open and didn't use the blowers before starting. Once the engine warmed up I switched the blowers on and the voltmeter dropped to zero and the engine quit. Turned on the ignition and tried to restart but no joy. LP fuel pump didn't even energize. All switches on the helm worked with the exception of the blowers.
I shut the batteries off for quit sometime while I cleaned connections, etc and tried starting again and she fired right up. As soon as I turned on the blowers the same thing happened again. I loosed the belt some and started sometime later and switched the blowers on and yet the voltage did drop momentarily it recovered and the engine didn't shut off. Weird... Any suggestions?

 

[Don S]

Re: Unexpected Engine Shutdown

What engine and drive package are you running? Including year.

What happens if you start the engine and don't turn anything else on ??????

 

[Brian D]

Re: Unexpected Engine Shutdown

Don S

I have a 1998 Monterey 276 with a single 7.4L (BY).

When I got the engine restarted it ran fine. This was before loosening the alternator belt. After it warmed up I switched on the blowers again and voltage went to zero and the engine shutdown.

I loosened the belt a hair and restarted. I switched the blowers on and all was well. I switched blowers on/off several time and on two occasions the voltage dropped to zero and I immediately shut the blowers off and the engine didn't shutdown.

 

[Rocky_Road]

Re: Unexpected Engine Shutdown

Has anyone experienced any issues such as starting the engine and switching all accessories on the helm (e.g. blowers, lights, etc) and the engine shut off?

I think it may be the alternator or voltage regulator. I had just tightened the alternator belt when the issue occured. I had the engine doors open and didn't use the blowers before starting. Once the engine warmed up I switched the blowers on and the voltmeter dropped to zero and the engine quit. Turned on the ignition and tried to restart but no joy. LP fuel pump didn't even energize. All switches on the helm worked with the exception of the blowers.
I shut the batteries off for quit sometime while I cleaned connections, etc and tried starting again and she fired right up. As soon as I turned on the blowers the same thing happened again. I loosed the belt some and started sometime later and switched the blowers on and yet the voltage did drop momentarily it recovered and the engine didn't shut off. Weird... Any suggestions?

You didn't mention whether you were using a single wire alternator...if you are, then it has what is called an exciter circuit that barely puts out at idle. Most exciter line diodes wait until around 1200 rpm's to generate the maximum amps. If your battery is just at the point where it will start the engine, and the engine is idling, and you increase the load (turn on accessories), you can get a stall. Give your battery a full charge, and go easy on the accessories until you are running above idle.

Happy boating!

 

[Brian D]

Re: Unexpected Engine Shutdown

You didn't mention whether you were using a single wire alternator...if you are, then it has what is called an exciter circuit that barely puts out at idle. Most exciter line diodes wait until around 1200 rpm's to generate the maximum amps. If your battery is just at the point where it will start the engine, and the engine is idling, and you increase the load (turn on accessories), you can get a stall. Give your battery a full charge, and go easy on the accessories until you are running above idle.

Happy boating!

Rocky

Not sure if it's a one wire system or not, I believe so. Regarding the batteries I have two cranking and two deep cycle onboard. Cranking batteries were very close to a full charge.

It appears that the blowers draw the most power on start up then the voltage would neutralize a little over 13 volts.

Thanks!

 

[Don S]

Re: Unexpected Engine Shutdown

single 7.4L (BY).

Seeing the BY, I have to assume you have a Volvo, if so, what's the full model number, is it carbed or EFI.
Every boat does not have the same engine, we need to know what EXACTLY you have to give any kind of help.

 

[Brian D]

Re: Unexpected Engine Shutdown

Don S

Sorry, yes it's a volvo 7.4L Gi with EFI and freshwater cooled. This is the only number I can find that may be the engine model number?

4110157020

 

[Don S]

Re: Unexpected Engine Shutdown

Yes, the 4110157020 is the Volvo serial number and says it all (to me anyway)
You have a 7.4GI PBYCCE [full model number]

What happens when you start the engine and let it run, without anything else electrical running?

 

[Brian D]

Re: Unexpected Engine Shutdown

Don S

With nothing on the helm switched on it runs fine and maintains just over 13-14 volts.

When I switch lights or the bilge there is a almost un-noticeable drop in voltage then it recovers. The issue only happened when I switched the blowers on.

Prior to this issue the week before I cleaned all the battery post with baking soda and wire brushed the terminals and connectors. Didn't experience any problems following.

The problem occured after I tightened the alternator belt yesterday. I replaced the belt about 4-6 weeks ago and it loosened slightly, maybe from breakin, so I decided to tighten up just a little.

The problem first occured after that. I started the engine and let it warm for a couple of minutes. Then I began turning on switches on the helm (courtesy lights, nav lights, bilge pumps, instrument lights, depth finder, etc.). The last thing I turned on was the blowers and that is when the voltage dropped to zero and the engine shutdown. When I tried to restart it was like no power at all. The lower pressure fuel pump didn't energize nor did the starter. Everything on the helm functioned with the exception of the blowers and their breaker was not tripped. I turned all batteries off for about 30 minutes I began removing all the alternator connections, cleaned and reinstalled. I switched the batteries back on and turned the ignition and it fired right up. After a few minutes I energized the blowers and it shut off again with the same results mentioned. I shut the batteries off and then loosened the alternator belt a tad and about 15 minutes or so later I turned the batteries back on and it started right up. After running for a few minutes I energized the blowers and the voltage drop between 1-2 volts then climbed back to 13+ volts. I let the blowers run for 3-5 minutes. I then shut them off and on repeatedly and several times the voltage dropped to zero but I was able to shut them off before the engine shutdown. Hope this helps!


On another subject, I noticed my radiator cap has a slight leak when at op temp. It's a octogon shaped cap with 22-24 lbs. Do you think i can find a replacement at a autoparts store or will I have to purchase one off the internet?

 

[Fun Times]

Re: Unexpected Engine Shutdown

[Quote][Everything on the helm functioned with the exception of the blowers and their breaker was not tripped.]

You keep saying Blowers, How manny blowers do you have going to one switch??? Normaly it's just one blower installed in the boat, But if you have two or more blowers going to one switch I could see something like this happening.

Also does the blower sound normal while starting it up? They do pull a lot of power down for how small the blowers are.

And like said before by Rocky-Road, Before you are turning the blower on, Are you getting the alternator excited by making sure the engine revs up to around 1200 rpms or so after start up?

Also have you tried keeping the rpms up high then turned the blower on just to see if it still wants to die, ect?

 

[Don S]

Re: Unexpected Engine Shutdown

The first thing you need to do is get the battery fully charged, then load tested.

 

[180shabah]

Re: Unexpected Engine Shutdown

The first thing you need to do is get the battery fully charged, then load tested.

What about the obvious question?

Why are you waiting until the engine is warmed up to turn on the blower? Death wish?

How much voltage drop to you get when you start the blower BEFORE the engine is running?

 

[Brian D]

Re: Unexpected Engine Shutdown

180shabah
I don't have a death wish. I had both engine doors open the entire day while trying to troubleshoot. I always run the blowers prior to starting when the doors are closed.
"How much voltage drop to you get when you start the blower BEFORE the engine is running?". I haven't checked the voltage drop without the engine running. How do I check for a voltage drop without the engine running, multimeter on the battery terminals?

 

[Don S]

Re: Unexpected Engine Shutdown

G E T
T H E
B A T T E R Y
L O A D
T E S T E D....​

 

[Brian D]

Re: Unexpected Engine Shutdown

boat teck

When I got the boat there were two blowers connected to the same switch.

Don S

I'll take both batteries in for a load test.

 

[Brian D]

Re: Unexpected Engine Shutdown

G E T
T H E
B A T T E R Y
L O A D
T E S T E D....​

Don S

Both batteries checked good on the load test. Any other suggestions?

 

[Don S]

Re: Unexpected Engine Shutdown

Now put the batteries in, put the cables on clean and tight and start checking connections. Something is loose or corroded causing a power loss. Problems like that can be a real pain in the ice to find at times.
It could be anything from a bad battery switch to the ignition switch, fuse panel, main harness connection, you name it.

 

[Brian D]

Re: Unexpected Engine Shutdown

Don S.

I figured what you stated once I reinstalled the batteries and the same problem reared its head. It seems to be related to the blowers so that may help me troubleshoot.

Today I had the engine doors open while reinstalling the batteries. Switched the batteries on and kept the engine doors open. I started the engine without the blowers running. As soon as I turned the blowers on the voltage dropped to zero and the engine quit. I turned off the ignition. Everything on the helm operated with exception of the blowers. The ignition was dead as if I never installed the batteries. After all those checks, I was preturbed and I decided to leave the blower switch on and 10-20 seconds later they started running. The ignition also began to work. It started right up. I switched the blowers off and back on and the voltage dropped and the engine shut down. I waited a few minutes, turned the blowers back on and no go until 10-20 seconds later they started and the ignition was functioning. Maybe I have a bad blower.

Last night on the way back from the boat parade I watched the gauges and the voltage was all over the place after about 20 minutes of running at 22 knots and 3400 rpm. I could tell that the engine was cutting on and off because the tach was dropping/jumping 400 rpms or more momentarily in conjunction with the voltage drop. I made it back to the marina. I am stumped with this one. I'll check my grounds and look for loose wires and corrosion.
I may have to resort to paying someone to troubleshoot or sell/give it to the Navy or Coast Guard for target practice.

 

[Fun Times]

Re: Unexpected Engine Shutdown

Don S.

I figured what you stated once I reinstalled the batteries and the same problem reared its head. It seems to be related to the blowers so that may help me troubleshoot.

Today I had the engine doors open while reinstalling the batteries. Switched the batteries on and kept the engine doors open. I started the engine without the blowers running. As soon as I turned the blowers on the voltage dropped to zero and the engine quit. I turned off the ignition. Everything on the helm operated with exception of the blowers. The ignition was dead as if I never installed the batteries. After all those checks, I was preturbed and I decided to leave the blower switch on and 10-20 seconds later they started running. The ignition also began to work. It started right up. I switched the blowers off and back on and the voltage dropped and the engine shut down. I waited a few minutes, turned the blowers back on and no go until 10-20 seconds later they started and the ignition was functioning. Maybe I have a bad blower.

Last night on the way back from the boat parade I watched the gauges and the voltage was all over the place after about 20 minutes of running at 22 knots and 3400 rpm. I could tell that the engine was cutting on and off because the tach was dropping/jumping 400 rpms or more momentarily in conjunction with the voltage drop. I made it back to the marina. I am stumped with this one. I'll check my grounds and look for loose wires and corrosion.
I may have to resort to paying someone to troubleshoot or sell/give it to the Navy or Coast Guard for target practice.[/QUOTE] If all this happened with the blowers off, Then the blowers should not be your problem, But because it sounds like you where running at night you may have had the lights on??? [Extra load]

You might want check to see if the alternator is getting really hot Or pull it off and see if someone can run a test on it Somewhere, Also you might want to check and feel all the battery cables and also power and ground wires with stuff running to see if anything is getting warm/Hot. Just an idea is all. Good luck.

 

[Brian D]

Re: Unexpected Engine Shutdown

Today after staring at wires for several hours I decided to start the engine. I turned on the blowers and the engine shutdown. Everything on the helm would work with exception of the blowers and the ignition switch. I left the ignition off switch on the blowers. I starting tapping the breakers on the front right engine riser. The blowers started working and the igniton was working. I must have rattled the starter or ignition relay, maybe one of these is sticking. I am thinking the ignition relay needs to be replaced. Any thoughts?