I/O Mercrusier 5.0 MPI randomly shuts off while driving in my 2002 JC Tritoon

[Corbinsc35]

Hello,

Recently I purchased a used 2002 JC Tritoon with only 160 hours on the motor. I made the mistake of purchasing the boat without testing it in the lake. We just hooked up a water clamp and tested the motor in a parking lot.

Well, first weekend out on the boat after cleaning it up we are having issues. The boat starts no problem, but it will randomly shut off without warning. The boat will instantly shut off without any beeps or noises. It doesn't sputter or anything it just instantly dies. It happens at all RPMS while the boat is on, but it happens more so while accelerating and increasing speed going over 2000 rpm without warning.

We first thought it was just bad fuel in the gas tank and the lines. So later that night we put some gas tank cleaner in the gas tank and changed the water separator fuel filter. Well, no luck it still happened the next day.... and the day after.

So we started a process of elimination and started cleaning and changing things out. We ended up checking the compression on the cylinders and the compression was fine. We changed all the spark plugs, the spark plug wires, the distributer cap, the rotor under the distributer cap, the coil, changed the starter, we cleaned and reattached grounds. We checked the emergency shut off switch, we changed the ignition.

We cant find the fuel pump or the other fuel filter. That was going to be our next guess but we are pretty stumped. I read somewhere on I-boats, from a forum in 2012 a guy had a very similar problem and said it was his shift interrupter switch. Supposedly all he did was installed the jumper wire going to the ECM... not sure what exactly he meant, but id love to know what exactly he did. I believe the users name is Dubie73. I checked our shift interrupter switch and it seemed fine to me.

We took the boat to a shop and their mechanic read the codes for us. Unfortunately, their printer was broken. So he wasn't able to print the full report, after the boat sat there for two days....
The codes he was able to read said:

Pitot pressure input low - active
Fuel level sensor input high - active
Steering angle input low - active
Trim input high - active


If anyone has a solution, if anyone knows Dubie73, or what to do... Id greatly appreciate your help.

Thanks

 

[alldodge]

Howdy
Just shutting down is an electrical issue.

When it dies, do you hear any beeps?
Does the key need to be turned OFF and back ON to start, or just turn the key and it fires right back up?

 

[tank1949]

Hello,

Recently I purchased a used 2002 JC Tritoon with only 160 hours on the motor. I made the mistake of purchasing the boat without testing it in the lake. We just hooked up a water clamp and tested the motor in a parking lot.

Well, first weekend out on the boat after cleaning it up we are having issues. The boat starts no problem, but it will randomly shut off without warning. The boat will instantly shut off without any beeps or noises. It doesn't sputter or anything it just instantly dies. It happens at all RPMS while the boat is on, but it happens more so while accelerating and increasing speed going over 2000 rpm without warning.

We first thought it was just bad fuel in the gas tank and the lines. So later that night we put some gas tank cleaner in the gas tank and changed the water separator fuel filter. Well, no luck it still happened the next day.... and the day after.

So we started a process of elimination and started cleaning and changing things out. We ended up checking the compression on the cylinders and the compression was fine. We changed all the spark plugs, the spark plug wires, the distributer cap, the rotor under the distributer cap, the coil, changed the starter, we cleaned and reattached grounds. We checked the emergency shut off switch, we changed the ignition.

We cant find the fuel pump or the other fuel filter. That was going to be our next guess but we are pretty stumped. I read somewhere on I-boats, from a forum in 2012 a guy had a very similar problem and said it was his shift interrupter switch. Supposedly all he did was installed the jumper wire going to the ECM... not sure what exactly he meant, but id love to know what exactly he did. I believe the users name is Dubie73. I checked our shift interrupter switch and it seemed fine to me.

We took the boat to a shop and their mechanic read the codes for us. Unfortunately, their printer was broken. So he wasn't able to print the full report, after the boat sat there for two days....
The codes he was able to read said:

Pitot pressure input low - active
Fuel level sensor input high - active
Steering angle input low - active
Trim input high - active


If anyone has a solution, if anyone knows Dubie73, or what to do... Id greatly appreciate your help.

Thanks

My guess is to have a friend or you systematically move wires near motor, especially grounds. You most likely have an exposed wire near or linked to ECM. Vibrations may cause wire to lose contacts.

 

[Corbinsc35]

Howdy
Just shutting down is an electrical issue.

When it dies, do you hear any beeps?
Does the key need to be turned OFF and back ON to start, or just turn the key and it fires right back up?

No beeps at all.
Yes I you have to turn off the key, and then it has no problem starting back up. The engine turns right back over and sounds great at idle. The boat only kicks off when it's in gear.

I decided to change the oil today, and it looked milky like there was water in the oil. The previous owner said he changed the oil last year and the engine was only ran "1" hour with the oil he put in the motor.... so looks like we have a leak somewhere as well. After I changed the oil and put new oil in the boat still had the same problem turning off. I don't think this has anything to do with the motor cutting off, I think its just another problem we are going to have to fix.

 

[Corbinsc35]

Hello,

Recently I purchased a used 2002 JC Tritoon with only 160 hours on the motor. I made the mistake of purchasing the boat without testing it in the lake. We just hooked up a water clamp and tested the motor in a parking lot.

Well, first weekend out on the boat after cleaning it up we are having issues. The boat starts no problem, but it will randomly shut off without warning. The boat will instantly shut off without any beeps or noises. It doesn't sputter or anything it just instantly dies. It happens at all RPMS while the boat is on, but it happens more so while accelerating and increasing speed going over 2000 rpm without warning.

We first thought it was just bad fuel in the gas tank and the lines. So later that night we put some gas tank cleaner in the gas tank and changed the water separator fuel filter. Well, no luck it still happened the next day.... and the day after.

So we started a process of elimination and started cleaning and changing things out. We ended up checking the compression on the cylinders and the compression was fine. We changed all the spark plugs, the spark plug wires, the distributer cap, the rotor under the distributer cap, the coil, changed the starter, we cleaned and reattached grounds. We checked the emergency shut off switch, we changed the ignition.

We cant find the fuel pump or the other fuel filter. That was going to be our next guess but we are pretty stumped. I read somewhere on I-boats, from a forum in 2012 a guy had a very similar problem and said it was his shift interrupter switch. Supposedly all he did was installed the jumper wire going to the ECM... not sure what exactly he meant, but id love to know what exactly he did. I believe the users name is Dubie73. I checked our shift interrupter switch and it seemed fine to me.

We took the boat to a shop and their mechanic read the codes for us. Unfortunately, their printer was broken. So he wasn't able to print the full report, after the boat sat there for two days....
The codes he was able to read said:

Pitot pressure input low - active
Fuel level sensor input high - active
Steering angle input low - active
Trim input high - active


If anyone has a solution, if anyone knows Dubie73, or what to do... Id greatly appreciate your help.

Thanks

Also the boat motor is the Alpha Drive version of the Mercrusier 5.0 mpi

 

[alldodge]

The boat only kicks off when it's in gear.

This would be a different issue, and it would be with the neutral safety switch. Most likely need to adjust shift cable

Back to your issue
Having to turn the key off and back ON it may be the key switch it self. Check the connections on it, along with check the switch with an ohm meter

 

[Corbinsc35]

This would be a different issue, and it would be with the neutral safety switch. Most likely need to adjust shift cable

Back to your issue
Having to turn the key off and back ON it may be the key switch it self. Check the connections on it, along with check the switch with an ohm meter

How would you adjust the shift cable?

I turn the key off and on, because when the boat dies. You have to turn the key to the left into the off position, and then to the right to the on position to turn the engine back on. I changed the key switch and it still had the same problem.

 

[alldodge]

If power was lost the motor dies, but if it comes back then all would be needed is to turn the key to start

Saying it has to be "in gear" means the shift cable needs adjusting, or the neutral safety is off. The neutral safety switch has no bearing on the motor running, ONLY when trying to start

Now if the term used prior means need to turn key OFF, shift to neutral and then restart then this is not neutral safety

 

[GuilT]

Hi, funny I just bought a boat this summer (although I do test it on the water) and had a very similar issue about 30 minutes in my first ride. Engine just suddenly shuts off. It would die as if it ran out of fuel or stopped firing completely. After discussing it with the mechanic that did the last maintenance on the boat we decided to change the coil as apparently an old faulty coil may do that when the engine gets a bit hot... it did not fix the issue.

As we changed the coil we decided to also troubleshoot why the engine temperature sensor was not working (disclosed by previous owner) and find out that the sensor wire is grounded somewhere. We then chase that to the wire that runs on along the top of the engine along the mating point of the intake/exhaust manifold. Sure enough that harness is in very bad shape as if it were accidentally squished when reassembling the valve cover and somehow grounded the temperature sensor wire on the engine block.

As we take it for a test ride with our new coil and working temperature sensor (redone the harness), we notice that we lose power from the alternator. We immediately come back to shore after a 10 minutes ride and verify that the alternator wires are all tight but do not see anything suspicious.

The next day we open the engine bay again to troubleshoot some more and test all the wires to the alternator and this time we notice the alternator AC tap pin is grounded. On my Volvo Pento 3.0L this wire is used for the electrical choke on the holley carburetor. Why is it grounded wire was redone 2 days prior as part of the harness rebuild. We notice the harness is melted in the exact same spot the old one was. At this point the cause was definitely a leak between the head and the intake/exhaust manifold blowing hot air on our harness and grounding wires randomly. Turns out our ignition wire was also in very bad shape and we suspect it was probably the cause of the engine stopping suddenly after some use.

We rebuilt the harness a second time and removed the manifold and to our surprise the intake and exhaust port did not match the ports on the head. Turns out our star mechanic put on a pre-1991 head on our 1998 motor thinking no-one would notice. The difference is so great that our head was sucking air straight and had way to much restriction on the exhaust due to a misfitting gasket and port sizes. That explains why it ran so rough and loud as well...

All that to say, check for damaged harnesses as part of your troubleshooting and keep going dividing and conquering.

 

[alldodge]

Someone tried real hard to be real cheap
Sounds like you got a mech that knows how to look

And its hardley ever the coil

 

[Corbinsc35]

Mercrusier 5.0 MPI shut down, beeped very rapidly, and now it wont do anything

Hello,

I have a 2002 JC Tritoon with a Mercruiser 5.0 MPI 305 I/O. The boat only has 170 hours on the engine, but is 18 years old. We recently purchased it this summer in June, because it looked so well kept up. After purchasing what we thought was a good buy we have had unfortunately nothing but problems. When we first ran it in the water the boat would randomly shut down while in gear after going over 1500 RPMS and it seems the engine area would fill up with lots of water. We had to basically keep the bilge on the whole time.

Since then we have done a lot of work on the boat over the past two months hoping to solve the two issues. We have spent countless hours trying to diagnose the problems and have used a process of elimination to try to fix the boat, as well as read the forums on what to do. So far we have changed the bellows, changed seals, and fixed up the lower unit, changed relays, changed the oil, put new gas in, changed the gear oil, changed fuel filters, cleaned the grounds, replaced the flappers in the exhaust, installed a new shifter cable, new key switch, changed out the shift interrupter switch, put new breakers in, and a few other things.

Today, 9/2/2020, we started the boat in the drive way to see if it was running well, and if it was ready to be put back into the water. After maybe a minute of idling with the water hose hooked up to the boat. The boat seemed okay and we were fixing to put the boat in gear to see if it would randomly die like it had on the water a few months ago. Out of nowhere the boat randomly shut off. As soon as it shut off there was about 20 rapid beeps or so that followed from the console area.

After the beeps and the engine shutting off we turned off the battery, turned it back on, and then turned the switch to see if the boat turned over, but nothing happened at all. When the battery is turned on the engine doesn't make any noise and none of the pumps turn on like normal. Everything else hooked up to the battery like the lights and stereo would still work though.

Does anyone know why my engine would randomly shut off and what the 20 or so rapid beeps means?

How can we diagnose this?

Does anyone know of any solutions?


Thank you!

 

[Corbinsc35]

Hi, funny I just bought a boat this summer (although I do test it on the water) and had a very similar issue about 30 minutes in my first ride. Engine just suddenly shuts off. It would die as if it ran out of fuel or stopped firing completely. After discussing it with the mechanic that did the last maintenance on the boat we decided to change the coil as apparently an old faulty coil may do that when the engine gets a bit hot... it did not fix the issue.

As we changed the coil we decided to also troubleshoot why the engine temperature sensor was not working (disclosed by previous owner) and find out that the sensor wire is grounded somewhere. We then chase that to the wire that runs on along the top of the engine along the mating point of the intake/exhaust manifold. Sure enough that harness is in very bad shape as if it were accidentally squished when reassembling the valve cover and somehow grounded the temperature sensor wire on the engine block.

As we take it for a test ride with our new coil and working temperature sensor (redone the harness), we notice that we lose power from the alternator. We immediately come back to shore after a 10 minutes ride and verify that the alternator wires are all tight but do not see anything suspicious.

The next day we open the engine bay again to troubleshoot some more and test all the wires to the alternator and this time we notice the alternator AC tap pin is grounded. On my Volvo Pento 3.0L this wire is used for the electrical choke on the holley carburetor. Why is it grounded wire was redone 2 days prior as part of the harness rebuild. We notice the harness is melted in the exact same spot the old one was. At this point the cause was definitely a leak between the head and the intake/exhaust manifold blowing hot air on our harness and grounding wires randomly. Turns out our ignition wire was also in very bad shape and we suspect it was probably the cause of the engine stopping suddenly after some use.

We rebuilt the harness a second time and removed the manifold and to our surprise the intake and exhaust port did not match the ports on the head. Turns out our star mechanic put on a pre-1991 head on our 1998 motor thinking no-one would notice. The difference is so great that our head was sucking air straight and had way to much restriction on the exhaust due to a misfitting gasket and port sizes. That explains why it ran so rough and loud as well...

All that to say, check for damaged harnesses as part of your troubleshooting and keep going dividing and conquering.

Yikes,

well after two months of trouble shooting on our boat we still cant figure it out. I changed my coil out and changed the spark plug wires. Im guessing Ill look a the exhaust manifold next and check for any melted harnesses.

Today we just finished rebuilding and replacing all the parts in the lower unit. We turned on the boat in the drive way with the water hose hooked up and after a minute the motor turned off. Then the console beeped about 20 times at us very rapidly. Now when you turn the key over nothing happens and when you turn the battery off and on the pumps don't do anything anymore... So not sure what the new issue is.

 

[alldodge]

Your previous thread had no mention of water constantly coming in

https://forums.iboats.com/forum/eng...shuts-off-while-driving-in-my-2002-jc-tritoon

Your last post in the thread listed the 20 some beeps

What is your serial number?
Where is the water coming from?
Does it do 20 beeps, stop and repeat with more beeps?

 

[ThomW]

I am not sure about the 20 or so beeps, but I believe that on some of the 5.0 MPI motors the alarm will beep for about 5 seconds--maybe that gives you 20 or so beeps--if there is low battery or low fuel pressure. Low fuel pressure could cause some of the issues you described.

 

[GA_Boater]

Your previous thread had no mention of water constantly coming in

https://forums.iboats.com/forum/eng...shuts-off-while-driving-in-my-2002-jc-tritoon

Your last post in the thread listed the 20 some beeps

What is your serial number?
Where is the water coming from?
Does it do 20 beeps, stop and repeat with more beeps?

Now it does, AD.

Corbin please keep all your posts in this thread about your issue. Alldodge made an excellent point.

 

[QBhoy]

Hi.
you can ignore the fault codes you listed. These are sensors you don’t have and will remain in alarm despite this.
I would look towards fuel issues or electrical and lanyard and main earth and battery issues

 

[1960 Starflite]

I have seen a few post about engine sudden shut down. This may not be related to this post.

I have a 1979 Century with the inline 4 cyl, 140hp engine and mine would randomly shut down under power. I did the throw parts at it thing and thought it was fixed several times. Then one day upon starting, nothing at Ign switch, no power to coil, no power to starter relay. I used my muti-meter and found no power to the newly installed Ign. switch.

I pulled the fuse (to switch) and found the end caps of glass fuse loose to tube and the nice white corrosion around the metal caps of fuse. Lesson learned (again). Electrical corrosion and Marine just a must check maintenance item. I pulled all the fuses from panel, cleaned with small SS wire brush, applied a small amount of electrical grease to fuse ends, reinstalled.

Cross you fingers for me, 15 hours, 4 trips on Lake, no shut down. Now where is that block of wood when you need it to knock on :facepalm:

PS: I do carry a jumper wire with an resistor and alligator clips to jump to coil just in case, yes I've used it before finding the fuse problem.