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-   -   502 not starting (https://www.offshoreonly.com/forums/general-q/354527-502-not-starting.html)

SB 06-11-2018 07:49 PM

The module is more common in the cars vs boats, but still have some go bad in the boats.

I repaired a boat yesterday that after 5 minutes on plane would sputter and then die. After an hr or so would restart like it had no issues.

Grabbed my $15 ignition tester as above and went for a quick ride. It died, it had no spark.

I have spare good modules (EST and Tbolt IV) and coils for the different systems .

Replaced the module as this is way more common than the coils and condition was still there. Replaced the coil and all good. BTW: I did quick check on coil first and it was not hot nor any oil leak.

I took the module back of course. Charged him for coil and my time. Not the sunburn. LOL.

BTW: If you ever change the module make sure to use real heat transfer compound like Arctic Silver or the like. Most of the 'compound' that comes with modules is clear which means it is dielectric grease which does not transfer heat. Heat is #1 module killer. Use compound sparingly, and use razor to leave very thin film. Leaving thick is inefficient for transferring heat.

That $15 spark tester is one of the best tools out there. Amingly one of the cheapest too.

GPM 06-11-2018 08:32 PM

[QUOTE=SB;4631475]The module is more common in the cars vs boats, but still have some go bad in the boats.

Between my brother and a friend they went through 5 in 2 seasons in their boats, could be the Chinese factor.

SB 06-11-2018 09:12 PM

I replace with ACDelco (if the EST) and mark my words on the heat transfer compound and read up on how to clean and apply.

All aftermarket companies modules are as reliable as the 86 Hyundai Excel.

Also, 99.9% of any module (OE and aftermarket)comes with got damn dielectric grease , even though it says heat transfer compound. I've been *****ing about this for almost 30 years when all the companies went dumb with this. This includes GM. Ford, and Chrysler.

Clear = dielectric. No good !

Get and use Arctic Silver or whatever your local computer company uses for ECU heat sinks.

BUP 06-11-2018 09:13 PM

one needs to differentiate is the issue fuel side or ignition or sensor side. If one is going to work and attempt to fix their apps properly - good tools are needed and all the proper service manuals. .

Odds would say to me without the testing factor the issue is NUMBER 8 in the link below. Buy the Merc one not sierra..

. MerCruiser 502 Mag. MPI Bravo (Gen. VI) GM 502 V-8 Distributor & Ignition Components Parts

BUP 06-11-2018 09:15 PM

Just an FYI its called the pick up coil. in the link above - Not a module

SB 06-11-2018 09:22 PM

You've run into more issues with the magnetic pick up vs the electronic module in the EST distributor? Interesting. I have totally different experiences. We are on fresh water if that matters.

BUP 06-11-2018 10:23 PM

17 year old to 25 year old electrical ignition component not going last forever. even spending its whole life boating in Lake water.. EST no start 1 st place Im testing is spark and fuel pressure ----- if no spark --- moving on with testing coil and the pick up coil. Odds are pick up coil for the ignition side. Cap and rotor SLIGHTLY in the mix depending on weather / humidity / corrosion and age. Most of the time engine will start but run poorly with bad cap / rotor.

Wharf Rat 1 07-04-2018 06:55 PM

It happened again. Same issue as before. Could bad gas present it self 1/2 to 3/4 of an hour into a ride? I've taken several rides before this for an hour or so and no issue. When we scanned the motor before, we found nothing out of the ordinary. I'm not a mechanic, so my investigation may not be up to parr. I'm thinking on getting rid of the fuel, but was told how expensive it is to dispose of it. So I would like to know before I do it.

Griff 07-04-2018 11:34 PM

It doesn't sound like the initial cause was ever found??
What was done to it after your last post on June 11???

Wharf Rat 1 07-05-2018 05:36 AM

We found a loose wire on the starter. With it hooked up to the computer, we couldn't find anything else. If it is bad fuel, could it be that intermittent?


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