Volvo Penta 5.7- weak/no Spark= Re-posted with engine specs

[shockwave2012]

Volvo Penta 5.7- weak/no Spark replaced plug -coil- new batts- distrib reg. ideas?

Here are the engine specs.

Volvo/Penta 5.7GLI PLKDCE

(NUMBERS BELOW )

4110152585-3868702

TRANSOM SX-C1

This is a re-post in hopes of some advice

I gave the boat a tune-up of 2 new battery's a new starter and new plugs 7 months ago.Since it had been sitting and needed it. Ran fine around the canal and full speed.

Then it sat from October to December when I went to start it it cranked for almost a minute, only after letting off the key did it fire up like a late spark kicked after key was turned off. I managed it for the night to show kids the Christmas lights.

2 months later tried to start again and it did the same hard start and this time backfiring while lowered from dock, and filled the engine pistons with water!

Dried everything out for a month, and since i have always noticed the coil pack has always been swollen and rusty, I changed it. I still got a random weak spark. Then no spark at all.

No I have no spark at all.

I have 12 volts going to coil.

I changed the ignition module under the distributor. after reading forums on this being the second option after coil pack.

I am trying to test coil pack to see if the back fire hurt it??

All of the fuses and breakers inside and outside engine bay seem to be fine ( not popped)

Battery's are strong and me and my dad are on the verge of calling a mechanic.

We ordered a manual and it was no help.

 

[Don S]

Re: Volvo Penta 5.7- weak/no Spark= Re-posted with engine specs

Do you have spark while cranking? Do you have voltage going to the coil while the engine is cranking, if so, how much.

 

[shockwave2012]

Re: Volvo Penta 5.7- weak/no Spark= Re-posted with engine specs

Hey Don, My Dad has been trying to help solve and did some more diagnosis today. He is drawing a schematic of what is happening at the coil pack. He wants to explain this and get your professional opinion. Thanks.

 

[Don S]

Re: Volvo Penta 5.7- weak/no Spark= Re-posted with engine specs

Backfires do not damage coils.

 

[shockwave2012]

Re: Volvo Penta 5.7- weak/no Spark= Re-posted with engine specs

Backfires do not damage coils.

Don,
It was not a backfire but a large spark from the coil output that should have gone to the distributor but arched to something next to the base of the coil output. Anyway, I have taken the time to make an attachment that will give you a better idea of what we are up against. In the meantime I have ohmed out the old coil and it ohms the same as the new one so I am confident the coil is probably fine. Take a look and feel free to use the designators in the illustrations I have included to help us understand where our problem might be.

Thanks,
Larry and Quentin Shock

 

[Don S]

Re: Volvo Penta 5.7- weak/no Spark= Re-posted with engine specs

Coils firing an arc to ground or to other terminals can cause cracks in the coil tower, and a cracked coil tower will arc to ground or other terminals. Especially if you have a bad cap, rotor, plug wires, or spark plug that isn't firing. Those 20,000+ volts are going to look for someplace to go.