Engine Problems-Please Help!

[BigKahuna]

Okay, here is what I have:<br /><br />1996 Bayliner 2655<br />5.7 Merccarb (2brl)<br />Thunderbolt V Ignition<br />No Knock Sensor<br /><br />My Problem:<br /><br />Engine starts fine first time. Warms up normally, oil pressure and all indications normal. After about 15-20 minutes the engine just stops. Engine will restart normally, run for 15-20 seconds, and then quits. This will repeat for about 5 starts, and then won't start. If I let it set for 10 minutes or so, it will restart fine and quit after 15-20 seconds.<br /><br />Here is what I have done for troubleshooting:<br /><br />Checked the water seperator-no water in the fuel.<br /><br />Checked the carb fuel filter (screen)-clean.<br /><br />Changed the coil-no change.<br /><br />Checked distributor cab and rotor-excellent condition.<br /><br />Checked fuel line from tank to water seperator-no blockage.<br /><br />Visually checked choke-appears to work normally (opens as engine heats up).<br /><br />Checked ignition module-pulled it off to see if it was getting warm when engine quits, feels normal.<br /><br />Checked to see if fuel was in carb when engine quit-no strong smell of gas in carb.<br /><br />After engine stops-moved throttle to full and can smell fuel in carb.<br /><br />I'm leaning towards the fuel pump, but the visual hose from the pump to the carb does not have fuel in it (supposed to indicate that the diaphram is damaged).<br /><br />Other than the carb and the float sticking, does anybody have any ideas? By the way, I have tapped on the bowl of the carb and no changes. The engine only has 200-300 hours in the last six years, I have had it since it was new.<br /><br />Could it be the Ignition module failing internally?<br /><br /> Thanks in advance!

 

[JasonB]

Re: Engine Problems-Please Help!

Ignition module failing when heated up?

 

[BigKahuna]

Re: Engine Problems-Please Help!

I don't know, that is what I'm asking as a possible answer to my problem. The module is not getting hot, but I guess that it could be failing internally. Has anybody heard of that? Is there a way to test it?

 

[crazyray78]

Re: Engine Problems-Please Help!

try heating module with an blowdryer see if problem happens faster if it does its a easy one

 

[FatBack]

Re: Engine Problems-Please Help!

Is the ign mod a rectanle box or a plate with a module glued to it? If box type it's really old and probably your problem. It's copied from the old ford design and they do exactly what your's is doing. $240.00 for a new one @ ebasicpower.com

 

[BigKahuna]

Re: Engine Problems-Please Help!

My module is a thin block, about 3/8 of an inch thick, about 2x3 inches. The backside of the module is stainless (looks to be) and the whole unit mounts on a bracket on the side of the distributor. According to the shop manual, there is supposed to be a layer of thermal grease on the back of the module, but there never has been any, so I doubt that is the source of the problem, but......<br /><br />My boat is a 1996.

 

[SlowlySinking]

Re: Engine Problems-Please Help!

Hi Mark, the thermal grease is required to ensure heat transfer from the module to the distributor body or it overheats and will give you the problem you have, put a thin layer of thermal grease and re-install the module, if it wasn't permanently damaged you might luck out.

 

[BigKahuna]

Re: Engine Problems-Please Help!

Shouldn't the module get warm? It doesn't, but maybe it shouldn't. I'm so confused.

 

[llerrad]

Re: Engine Problems-Please Help!

Had same kind of problem with mine did all the electrical stuff and found fuel line blocked from the pump to the carb. there was a build up of crap from the fuel filter looked like cork. Engine ran for short time then quit start up again and run and quit blockage allowed small amout of fuel to flow.

 

[magster65]

Re: Engine Problems-Please Help!

Check your gas tank vent for blockage. See if you're losing your spark or fuel when it won't start.

 

[FatBack]

Re: Engine Problems-Please Help!

Get a Merc manual and read trouble shooting. There are test in there for module. Since it is a 96 it probably is fuel related. Get a manual.

 

[BigKahuna]

Re: Engine Problems-Please Help!

I appreciate all the help everybody is offerring, but.....I have traced fuel lines, there is no blockage, no vapor lock, vent lines are clear. I'm just finding it hard that nobody else has had this problem or heard of it. Keep trying guys.<br /><br />And I do have a manual, but it talks nothing about checking the module. And the troubleshooting guide is fine if you are trying to chase a spark or something. This engine runs smooth as silk for 20-30 minutes, and then just stop.

 

[kdmiller8251]

Re: Engine Problems-Please Help!

I had a similiar problem, The boat would run for 10-20mins, Then would slowly loose power and die..<br />Would have to wait 20mins then would start up and run again, then die.... If I loosened the Fuel/Water Filter which was new. and dumped it. I could get it restarted right away and would not have to wait.. Try that and see what happens....<br /><br />Only problem I have is that, the problem went away after about 2 weeks.... Never did find out what was causing it..... Sorry....<br /><br />I would be curious to hear though if my method has any effect on it...<br /><br />tallman

 

[SlowlySinking]

Re: Engine Problems-Please Help!

Hi Mark, I can read your frustration but hang in there. Question: when the engine stops does it spit and sputter and stop or does it just stop smoothly like you turned the ignition key off? This info will provide an important troubleshoooting clue. Always remember the basics, you need fuel and spark to run, if one quits the engine stops, The first thing to determine is which is missing, after the engine quits look into the carb and pump the gas, do you see gas squirting in from the accelerator pump circuit? If yes then it seems to rule out a loss of fuel, now disconnect a spark plug wire and connect to a spare spark plug, set it on the engine block or metal part and crank the engine, do you see a spark. If not then add the silicone grease to the module and when the engine starts <br />see if it runs normally longer than now, if it still stops touch the module and see how hot it gets, excessive heat makes electronics do strange stuff. Check this and post your findings.

 

[BigKahuna]

Re: Engine Problems-Please Help!

Thanks for your input.<br /><br />The engine always stops as if somebody has turned the key off.<br /><br />Last night we went back down to continue the troubleshooting, this time I had help. We changed the anti-siphon valve (didn't think this was the problem), no change. We verified that there is fuel, you can physically see the fuel in the carb. And by advancing the throttle, you can see fuel squirt into the carb.<br /><br />Additionally, even though I had previously checked the fuel vents, we unscrewed the fuel cap and ran the engine like that, just to make sure that there was no vacum problem in the take.<br /><br />We did check the spark, and we are getting spark until the engine quits, and it is just like somebody turned the key off.<br /><br />We did find some limited troubleshooting for checking the module.<br /><br />Like I said, this is repeatable and happens after things are warmed up, not hot, but electronics might not be hot to fail.<br /><br />Thanks.

 

[SlowlySinking]

Re: Engine Problems-Please Help!

Hi Mark, good work on the troubleshooting, you eliminated fuel as your problem so it has to be and as you noted there is no spark when it quits. Next thing to do is add the heat sink grease for the module to provide better cooling and try it again, the time related repeatablity of the problem certainly sounds heat related, it's not from something like a loose connection. Now there's a very good chance that adding the grease will allow the module to run cool enough to solve the problem, the fact that it restarts and runs for a while seems to indicate that the module wasn't damaged. The module and distributor may look flat but they never make a perfect connection for proper cooling. The thermal conductive grease fills the gaps and conducts the heat to the distributor. The heat sink thermal grease is available at any auto parts store or Radio Shack. So, give it a try and let us know what happens.

 

[bernieb]

Re: Engine Problems-Please Help!

Try rapping gently on electrical parts while running and you may take a real close look at the gas tank ,the pick up tube may be sucking up on occasion a small piece of trash....most larger tanks have baffels (a partition)that can hide trash. Check small filter at carb.I put mine in backwards once .good luck.

 

[BigKahuna]

Re: Engine Problems-Please Help!

Sorry guys, no joy. Keep thinking, somebody must have come across this!

 

[llerrad]

Re: Engine Problems-Please Help!

Change the pick up coil, (Hall effect) under the rotor for high energy ign. system.

 

[capri]

Re: Engine Problems-Please Help!

HI SOULD LIKE YOU ARE GETTING HELP BUT YOUR CHECKING THE RIGHT THING BUT IF YOU ARE STILL HAVING A PROMLEM YOUR MISSING SOME THING AND IT MOST LIKEY SOME THING SO SIMPLE WELL THAT IS THE WAY IT WORKS FOR ME MOST OF THE TIME <br /><br />SOUNDS TO ME YOUR CHECKING THE RIGHT THINGS BUT IT GOING TO BE A PROSEESS OF ALIMINATION<br /><br />FUEL CHECK IT WHEN IT QUITS TAKE OFF AIR CLEANER LOOK DOWN THROAT OF CARB AND MANUALLY PUSH THE ACCELLERATER IF YOU SEE FUEL SQIRT OUT ITS NOT FUEL PROBLEM OK THAT EASY<br /><br />SPARK IS A BIT TRICKER<br />I HAVE ALL KINDS OF ING PROBLEM AND FINALLY MADE A SPLITTER IN THE COIL WIRE AND GROUNDED A PLUG SO WHEN IT QUIT I COULD SEE IF I HAD GOOD SPARK OF NOT <br />OR WATCH IT WHILE IT RAN MOST TIME I WAIT TILL DARK AND SO YOU CAN SEE BUT IN MOST CASES YOU DONT HAVE TO DO THAT BUT I TELL YOU IF YOU HAVE SOME THING ARKING IT WILL SHOW AT NIGHT<br /><br />THE PROBLEM IS IF YOU DONT KNOW WHAT CAUSEING BAD SPARK ITS HARD TO CHANGE THE RIGHT PART<br />AN MOST LIKE LIKE YOU I HATE TO SPEND MONEY OH THE WRONG PART<br /><br />YOU MAY HAVE EXTERANAL COIL THAT IS BAD OR MODULE<br />COILS SEEM TO HAVE A TENDACY TO WORK SOME TIME AND THEN NOT WHERE MODULES MOST TIMES JUST FAIL<br /><br />HOW EVER ITS RARE THAT IF THEY WORK ONE MINUTE AND NOT THE NEXT THAT IF IT WILL RUNN AT ALL IT WILL RUN NORMAL WHEN IT RUNS SO LOOK AT EXTERANL COIL<br /><br />WHAT I CALL MUDD BEES THEY LIKE TO PLUG OFF VENT LINES EVEN THOUGHT YOUR VENT LOOKS OPEN AT THE END LOOK DEEPER USE AIR AND BLOW ALL LINES OUT<br /><br />NOW IF YOU YOU HAVE ANY KIND OF SAFTY SWITCHES<br />IVE HAD PROBLEMS WITH THOSE SHORTING OUT <br />THERE DESIGNED TO CUT THE MOTOR WHILE SHIFTING AND IF THAT MODULE GOES BAD THAT COULD STOP YOU MOTOR TO <br /><br />IN MOST CASES YOU CAN BY PAST THAT FEATURE TO TEST IT AND SEE IF THAT COULD BE YOUR PROBLEM<br /><br />HOPE THIS HELPS LET ME KNOW IF THIS DOES