2001 5.7 Merc Bravo3 random shut off

[reelentless]

Hi all, <br /><br />I have a 2001 5.7 Merc (carb) with a Bravo 3. She runs beautiful, but sometimes out of the blue the engine just dies. I havent been able to figure out any pattern yet either. It happens at idle, WOT, or just crusing. Feels like someone just killed the ignition. After the motor dies, it wont start until you throw it neutral and give it soem gas and the she will start right up, idle for a minute then die again. This will go on for about 20 - 30 minutes and then everything is back to normal. I replaced the fuel/water seperator filter and check the vent. Any ideas or places to start would be appreciated. <br /><br />Thanks, <br /><br />Ray

 

[rodbolt]

Re: 2001 5.7 Merc Bravo3 random shut off

hello<br /> oh ohhhh<br /> well next time it dies and you suspect fuel, have someone crank the engine while you feel/listen for the electric fuel pump. some of the pumps worked iffy. you may also have a pump cvontrol problem. it sounds almost like a fuel restriction causing a vapor lock. I hate some of the intermittant problems as they can cause lengthy troubleshooting times. if it is running out of gas the engine will make specific sounds associated with fuel starvation. this is when you pay me for what I know not what I do. just remember the fuel and ignition systems are just subsystems. eliminate each as a cause<br /> good luck and keep posting

 

[reelentless]

Re: 2001 5.7 Merc Bravo3 random shut off

rodbolt thank you for the reply. I will give that a shot. What exactly should I be listening for? Also how would I begin to troubleshoot the potential pump control problem? <br /><br />Thanks

 

[BRIAN03]

Re: 2001 5.7 Merc Bravo3 random shut off

When the boat dies. Does the dash (all the guages) all lose power. If so I would check the cannon plug on the engine. Main harness that plugs in the engine.

 

[reelentless]

Re: 2001 5.7 Merc Bravo3 random shut off

No. That's what is so strange. Any other ideas? <br /><br />Thanks,

 

[BRIAN03]

Re: 2001 5.7 Merc Bravo3 random shut off

You need then to watch the fuel pressure.

 

[navigator336]

Re: 2001 5.7 Merc Bravo3 random shut off

From your description, it sounds like the engine is running fine then instantly shuts off. Is this the case or does it sputter and run rough a little then die. I've never had any carbureted vehicle run out of gas without running a little rough first. If it is shutting down instantly, I'd lean towards electrical. Whatever it is it seems heat related based on the 20 to 30 minute "cooling off" period.

 

[rattana]

Re: 2001 5.7 Merc Bravo3 random shut off

Hi Ray<br /><br />Did you check out the shift interrupt switch, it could be that it is out of adjustment and could be what is shutting you down. Does it happen when you are accelerating or when you are at steady throttle? Check the limit switch where the shift cable bracket is on your block.<br /><br />Kevin

 

[navigator336]

Re: 2001 5.7 Merc Bravo3 random shut off

Sorry, I forgot to ask if it will restart without pumping the throttle first.

 

[kenimpzoom]

Re: 2001 5.7 Merc Bravo3 random shut off

Keep a timing light connected and when it dies, check to see if it has spark.<br /><br />An instant death with a carb engine usually means ignition.<br /><br />Ken

 

[wheels4]

Re: 2001 5.7 Merc Bravo3 random shut off

Im leaning towards the ignition module.Do as kenimpzoom suggested and check for spark when it dies.If you do not have a timing light you can get a spark tester pretty cheap.They go between your spark plug and wire and you can see the spark.If it sputters out then I would lean towards fuel.(vapor lock)

 

[reelentless]

Re: 2001 5.7 Merc Bravo3 random shut off

navigator336 -- that makes perfect sense if it is running out of fuel it will sputter. Here is what happens though. The boat runs great then instant off. After the initial shutdown it will start back up (even if you dont give it gas) it just takes longer. That is when the sputter starts. Sometimes it lasts 30 minutes other times it gone it 2 minutes. I did recently have the shift cable replaced. What is the function of the shift interrupt switch? Would I be able to find a spark tester an auto parts store?

check for spark when it dies

can you give me alitle more on this. Would i be looking for spark on the restart? <br /><br />Thanks guys<br /><br />RAy

 

[rattana]

Re: 2001 5.7 Merc Bravo3 random shut off

There are a few ways to check for spark when it fails. One way is to pull a plug wire and put a known good plug on the wire and make sure it is grounded on the block, crank it over and see if it sparks. ( don't get zapped!! ) An another way is to connect a 12 volt automotive test light across the +/- wires on the coil. The test light will flash on and off while cranking. This will show if the coil is getting the power to run, and would rule out anything interrupting the power to the coil such as the shift interrupt switch, etc. A good way is to use the timing light to see if it flashes while cranking. If it flashes the plugs have to be getting spark. A little more work but very good way to confirm spark. If you don't have a timing light you can use the first or second method. I would suspect the shift cutout switch if you had the shift cable replaced and especially if all the problems started after that time. The shift interrupt switch momentarily kills the engine as you shift from forward to neutral to reverse, etc. This takes the load off the drive and allows smooth shifting. If it is out of adjustment it could cause the problems you are experiencing. I think Trent or another poster had a link to adjust the shift cutout. I could find the site if you find that it is the problem. Like one of the other posters said there are just a few requirements to make a engine run, rule them out one by one. If the spark is there, then check the fuel system, etc.

 

[reelentless]

Re: 2001 5.7 Merc Bravo3 random shut off

Thanks everyone for the great input! I will be trying all this things out this weekend. <br /><br />Have a great weekend. <br /><br />Ray

 

[johnkc]

Re: 2001 5.7 Merc Bravo3 random shut off

check the sensor in the dist ,if it is grey it probably is the problem. had a bulletin on these about this year. don't remember the exact bulletin #,sorry.

 

[reelentless]

Re: 2001 5.7 Merc Bravo3 random shut off

After trying all of your tips I think that I have narrowed it down to the coil. Since the problem is intermittent, I went through each connection and checked for good clean contacts. Everything looked good until I got to the coil. The lead from the coil to the distributor was covered in grease. I pulled the coil side connection and it had a real gummy type of grease that didn’t look like it belonged there. After cleaning the contact and plugging it back in she started with no hesitation and ran great while hooked up to the hose. I didn’t get a chance to put her in the water and test because of bad weather. Is there any reason there should be grease in the coil? Is it possible that it is some type of gunk used to keep the coil contacts dry? Any thought would be appreciated? <br /><br />Thanks,<br /><br />Ray

 

[rodbolt]

Re: 2001 5.7 Merc Bravo3 random shut off

hello again. it could be a coil. what ign system do you have?<br />and the bravo3 does not have the interupt switch. there were some tch bullitins about moisture in the cap area.<br /> narrow it down and eliminate each subsytem as a culprit and Voilia it will be fixed

 

[navigator336]

Re: 2001 5.7 Merc Bravo3 random shut off

If it was on the contact surface area between the pins and the sockets, and it was GUMMY, it shouldn't be there. It's not uncommon to use a di-electric grease on contact surfaces, but it is silicone based and not gummy, greasy yes, but not gummy. A neoprene or vinyl based contact coating is used sometimes over the top of the joined connections but not between them and for your ignition I'm guessing you have an Accel Super Coil for GM applications ( square shaped yellow coil). The boot covered connector on these is pretty well protected from the elements already. I had one of these quit on me recently that was only 3 years old. Engine started flawlessly every time until the day I had 8 relatives loaded on board ready to leave the dock and it was totally dead. I replaced it with an MSD equivalent. Both the MSD and Accel are readily available at auto parts stores for about $40 -$45.

 

[Knightgang]

Re: 2001 5.7 Merc Bravo3 random shut off

Sounds like it could be coil. I know this story is about a truck and not a boat, but we are talking about an inboard engine (auto engine).<br /><br />I had an '82 Ford truck with an inline 300 cid, with an electronic ignition and standard coil. I don't know what happened, but it started running rough and skipping and then got to where if you shut it off with the engine warm, it would not start back up. After a tune up, new plugs, wires, and alot of head scratching, I replaced the coil on a "Well, I haven't tried this" hunch. It worked. Something in the coil would cause it to begin to cut up, when it got warm, and it was worse the more electrical strain you put on the system.<br /><br />I would try the coil if you think that is what it is, and if it does not work, you have an extra for when that one goes bad.

 

[Ron McC.]

Re: 2001 5.7 Merc Bravo3 random shut off

Hi,I have the same year and set up with the bravo 111 in my 26' I/o The symptems you mentioned were exactly the same with my boat last fall-I thought it was fuel-as I left the harbor with son and his family on board she started to miss again. When I got to open water I gunned her and did a couple of 360,s to 'clean' her out. She smoothed out and we headed out to the islands 12 mi. out,shut down and had a picnic. Got back on board and she cranked but was lifeless.Tried everthing then called Sea-Tow. Then dealer said to bring it in in 6 weeks.I asked for the service manager and he told me to pull a plug and tell him the color of the spark. It was yellow-he said it should be blue-replace the coil and rotter and call him back. Its run like a dream ever since. I now carry a spare on board as insurance. Hope this helps-Ron