Mercruiser 7.4 LX MPI Won't Start - No Sparky

[tpenfield]

Today was a perfect boating day . . . So, naturally the starboard engine would not start. :facepalm:

The Port engine started right up, but the starboard engine was having nothing of it. . . numerous attempts.

So, I called back to the house and told the family that it looks like a beach day instead of boating.

I got my computer/Diacom and hooked that up to see if there was anything obvious, codes, etc. No Codes
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I tried feeding the engine some fuel, but it did not make a difference. So, I went about trying to verify a spark. It did not look like there was a spark (using a test sparkplug on the #2 plug position, since that is the easiest to reach)

I also checked a bunch of fuses, connections, etc . . . Everything looked OK - the fuses all tested out visually and by an ohm meter.
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I got 12 volts to the coil and 12v coming out of the coil that leads to the distributor, as shown in the diagram.

The only thing left (it seems) is the distributor module, but it was getting late, so I'll check that in the AM.

I was able to verify the voltages that I was getting at various points around the engine harness by comparing them to the port engine. The port engine showed a nice spark on the test spark plug, the starboard engine showed nada, nothing on the test spark plug.

So, I thought I'd post this for the experts to see if I am missing something. or any other ideas on what to check. :noidea:

Calling . . . achris alldodge Scott Danforth muc

or anyone else ?

TIA for any ideas . . .

BTW - the distributor module looks a little pricey and not highly available ( :noidea: ) I would think there is a GM equivalent . . .

 

[tpenfield]

BTW - I should mention that the Starboard engine did not want to start a couple of weeks ago, but did eventually started after waiting a couple of minutes. Yesterday we ran the boat with no issues.

 

[alldodge]

When cranking do you see 300 rpm or more on the tach?

Prelim checks to the Distributor

 

[Scott Danforth]

Follow the info posted by AD.

The delco dizzy module

https://www.amazon.com/ACDelco-D1943A-Original-Equipment-Ignition/dp/B000BYGD7E

 

[tpenfield]

Thanks guys. I’ll be back at it in the AM.

The boat sure knows when the worst times are to act up.

 

[tpenfield]

Follow the info posted by AD.

The delco dizzy module

https://www.amazon.com/ACDelco-D1943A-Original-Equipment-Ignition/dp/B000BYGD7E

I'm finding references to ACDelco D1965A as being the 'marine' version of D1943A Wondering if there is any real difference :noidea:

 

[Scott Danforth]

Most likely the timing curve. Here is D1965A

https://www.motorcityreman.com/gmoe1016d1.html

https://www.amazon.com/ACDelco-D1965A-Original-Equipment-Ignition/dp/B0012PPPNO

 

[alldodge]

Summit list the D1943A as for 4 and 6 cyinders
https://www.summitracing.com/parts/ado-d1943a

The D1965A doesn't show where used
https://www.summitracing.com/parts/ado-d1965a

And walmart has it at $40
https://www.walmart.com/ip/NEW-IGNIT...0487/188617441

The Merc 8M0123099 is listed as not in stock and with a quick search everyone is out of stock also

The EST module should be for any number of cylinders because its all in how many times the pole passes by. This is why many list the module as 4, 6 and 8. The ECM controls the advance curve

 

[JustJason]

Start with some of the basics. Does the rotor turn when you crank the engine over? Does the inside of the cap and rotor look good or crusty? Is there continuity on the main plug wire between the cap and coil? Did you ohm out the coil to see if the coil failed or not?

 

[tpenfield]

Quick update . . .

The coil failed the Ohms test (#5) showing an 'open' circuit (It passed the other test #3 & #4.

The ignition module has a P/N '399 5J18' printed on it. The small screws are rusted beyond hope and I could not remove them. So, I pulled the entire distributor to bring back the the house.
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Really rough looking so I'll clean it up a bit and see what I can do about getting the ignition module off.

Is there anyway to test the ignition module? :noidea:

Probably should get new components anyway.

The distributor cap contacts look pretty bad, but I think I have another cap in the spare parts drawer. :thumb:

 

[tpenfield]

Looks like I got to take the center shaft out to replace the coil in the distributor . . .
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I think I'll be getting parts for the following . . .

Coil 811639T

Module 8M0123099/811637 (GM 399 5J18 ???) I think there is an even newer P/N for this . . .

Rotor 8M6001253/808484

Cap 808483T3

I'll see what I can get for GM equivalent part numbers . . .

With the whole fam damily down for the long weekend, we are going to 'limp' the boat over to a sandbar within the harbor. The real negative thing of the starboard engine being out is that the power steering runs off that engine

 

[alldodge]

I'm not able to find the number, but I'm pretty sure a GM dealer could find it

Don't know of any way to test the module, it either works or doesn't.

 

[Scott Danforth]

here is a whole dizzy, however not sure it helps you this weekend

https://www.myinboardmarine.com/products/distributor-gm-delco-5-0l-5-7l-7-4l-original-pcm-ra107039d


I tried checking the worst marine store near you Ted and couldnt get anywhere with their website.

 

[tpenfield]

I tried checking the worst marine store near you Ted and couldn't get anywhere with their website.

Thanks, Scott . . . Which is the worst marine store near me ? :noidea:

 

[Scott Danforth]

West Marine......

 

[tpenfield]

I might buy the complete distributor, rather than fuss with the old one(s). If I replace the starboard engine dizzy, I should probably do them both. $800 ish, using Scott's referenced source. (thanks)

 

[tpenfield]

I found Genuine ACDelco EST Marine Distributors (aka Mercruiser 805222A1) for $310 from a marine parts source :thumb:

So, that will help the beer supply money.

Mercruiser MSRP is $778

 

[alldodge]

Do make sure they have them, some list but don't have them, back order.

Could get one to get you thru the season and then rebuild the other.

Wonder what GM dealer could get them for

 

[tpenfield]

Do make sure they have them, some list but don't have them, back order.

Could get one to get you thru the season and then rebuild the other.

Wonder what GM dealer could get them for

Yes, this was from eBay, and it said 10+ were available. So, hopefully . . .

There was another Delco distributor that I found on the web for about $250, but probably was not the Marine SAEJ1171.

 

[tpenfield]

I took the boat out in the big ocean today on 1 engine. .

It could only go about 10 mph and 2000 RPM without really pushing it.