Engine Quits

[rcflyer]

I have bought a 1996 Sea Ray 240 with the 5.7 L with Bravo III out drive and has the Thunderbolt ignition. My problem is when the temp gets up to 160 or higher the engine quits and will not restart until cools down. The marina replaced the coil and the dist. pickup, same problem, they then replaced the ignition control module same problem, they then said the carb needs rebuilding did that same problem. engine runs fine in the slip the temp stays at 130 only when running the boat and the temp gets up to 160 is when it quits. No warning it's like I just turned the key off. Any help seeing the marina can not seem to find the problem. This only started after I fill the boat up with new gas ran fine with old tank of fuel, I did change the filter/ separator.

 

[Bondo]

Ayuh,.... Welcome Aboard,.... The only way to diagnose such issues is with a test light, When it dies,....

 

[rcflyer]

While cranking the timing light does light.

 

[alldodge]

While cranking the timing light does light.

Gas is just coincidence

Where are you at when looking at the test light?
Is this an EFI motor?

 

[rcflyer]

I am on the number one spark plug. And the motor is Carbed. Not EFI

 

[alldodge]

With the timing light flashing then there should be 12V on the + side of the coil. When the motor dies take a meter and verify 12V is there. Next have someone pump the throttle and see if fuel squirts down the throat.

 

[rcflyer]

I am getting fuel I can smell it as I am trying to restart it for awhile, I also see the butter flies are wet with fuel. I did take a jumper wire from the plus side of the battery to the plus side of the coil still did not start. I did not check if the 12V was there after it died. Right now the boat does start and will idle in the slip because the temp does not get hot enough to shut the motor down like it does when I am running it.

 

[alldodge]

Sure sounds like your loosing spark. The weird thing is the 160 degree shut down. Your comment of the motor getting above 160 could be another issue.

Have you checked to see if the gauge is correct, with like an IR temp gun?
It doesn't act like its over heating?
Also is the ignition module of the riser or distributor?

Check the ground coming from the module to its location for corrosion and a good connection. Take a look at the distributor and see if there are 3 wires coming from the base. Of the 3 wires follow the black wire to make sure it is grounded. It won't be the first time a new pickup was defective. Need to get it to shut down and check for 12V at the coil and then check for spark.

 

[rcflyer]

I do not have a IR temp gun to check, also the motor does not feel hot, I did make sure I have a good ground and no corrosion on the module bracket, it is mounted on the side of the distributor. The symptom sounds like it is still a bad pickup in the distributor, I hate to buy another one to only see that it still did not fix the problem, the Marina has to order the part and they charge me $80.00 for it even though I can buy it for half the price on the internet. Maybe I will try another one.

 

[alldodge]

Are you sure all the parts that was said to be replaced, where actually replaced? Did you get the old parts back

 

[rcflyer]

Yes I did the replacements myself. They did the ICM seeing they had to rewire the harness for the new one, they could not get the direct replacement, Merc told they what to use, and they seemed to have lost the old one. I can see that it is new they gave me the box the new part came in and it does say it is for a 7.4L bravo III. I did the coil and dist pickup so I have those parts.

 

[alldodge]

Installing a 7.4 module on a 5.7

 

[rcflyer]

No I have a 7.4 motor sorry I see I wrote that it was a 5.7 my fault.

 

[nola mike]

Why do you guys think it's ignition if he's getting spark at #1? Although timing light does not necessarily= actual spark

 

[alldodge]

they seemed to have lost the old one

Don't know if you can trust them, but a working TB5 module is worth a couple hundred, so they may want to sell it to another some time.

Why do you guys think it's ignition if he's getting spark at #1? Although timing light does not necessarily= actual spark

OP said he saw the light and also smells gas, so one of them is not working.

Need to get the motor to shut down then find out which is not present. I'm thinking electrical because it just quits.

 

[rcflyer]

The boat will ideal all day in the slip at 140 on the temp gauge, when I run it and the temp gets to 160 it quiets like you shut the key. It will not restart and as I am cranking it for a few minutes you can smell the gas fumes, I also can see the fuel being spraying into the carb. the timing light is flashing as it is cranking. The tach is not jumping which the mechanic says that it is the pickup in the dist. Once the temp drops down to 100 the tach does jump while cranking and it will restart. there is no coughing or stumbling or hesitation which says that it would be a fuel issue. Is there a temp sensor that will shut the engine down if it thinks it is to hot?

 

[alldodge]

Here is the thing, if there is spark and fuel, it will run.
You see and smell fuel so this isn't the issue, its spark. Need to know if your getting full 12V and full spark.

I would try this first, remove the gray wire off the - side of the coil and see if it still happens. The one caveat is the motor getting to 160, which it should stay below the 160 and more in the 140 to 150 range

 

[nola mike]

Or pulla plug and see if you're getting an actual spark when it's misbehaving. And if you feel like being fancy see if your spark is at the right time.

 

[rcflyer]

The mechanic says that the 160 - 170 is okay when I am running at 3/4 throttle. He also said yesterday that there is no temp cut off switch on this motor. He is going to call Merc on Tuesday and see what they have to say. Hope they will have some answers. Thanks for your comments, will let you know what happens.

 

[alldodge]

The mechanic says that the 160 - 170 is okay when I am running at 3/4 throttle

I'm sure there is other mechanics that will say 180 is OK also.