Mercruiser 3.0 No Spark issues

[alldodge]

I think your good

 

[aidanmurphy]

Cool. Will get one hopefully by the weekend and update back

 

[Scott06]

Pretty sure these are the modules to fit can google any of those numbers to find it at multiple sites

 

[aidanmurphy]

Just ordered the Sierra unit from amazon

Amazon.com

Thanks again.

 

[aidanmurphy]

Thank you guys for all your help. Today I replaced the dist cap, rotor, all spark wires and the ignition module. Boat started right up and runs great. Only concern I have is that at WOT there is a distinct pinging/ticking nose from the motor. It only happens at 90% or above throttle. Also noticed a slight (3-4mph on GPS) decrease in top speed at WOT. Does this sound like detonation? Boat runs perfectly other than that. Could being a bit off timing cause this? I marked and thought I had the dist back in the exact position, but it could be off a couple degrees if that would cause the detonation. Other than that very satisfied and thanks again to you guys for your help.

 

[Scott06]

Thank you guys for all your help. Today I replaced the dist cap, rotor, all spark wires and the ignition module. Boat started right up and runs great. Only concern I have is that at WOT there is a distinct pinging/ticking nose from the motor. It only happens at 90% or above throttle. Also noticed a slight (3-4mph on GPS) decrease in top speed at WOT. Does this sound like detonation? Boat runs perfectly other than that. Could being a bit off timing cause this? I marked and thought I had the dist back in the exact position, but it could be off a couple degrees if that would cause the detonation. Other than that very satisfied and thanks again to you guys for your help.

Check the timing with a timing light. Yes sound like detonation. could also be from being lean but start with verifying timing at idle in base mode is correct, and at full advance

 

[aidanmurphy]

Will get a timing light and check. Does boat need to be in the water to check or on muffs is fine?

It could be from being lean but I don't recall it making this sound under WOT before I pulled this dist and I have went through the carb since. Very clean

 

[nola mike]

Could being a bit off timing cause this? I marked and thought I had the dist back in the exact position, but it could be off a couple degrees if that would cause the detonation. Other than that very satisfied and thanks again to you guys for your help.

Absolutely, being too advanced. You can't time an engine with anything but a timing light.

Will get a timing light and check. Does boat need to be in the water to check or on muffs is fine?

Muffs is fine.

 

[aidanmurphy]

Okay thanks. Will try to get to timing it this week. Could the detonation events have caused any serious / permanent damage? Anything I should check?

 

[alldodge]

If you haven't lost any power your probably ok. Only way to check is with a bore scope inside plug holes, otherwise have to pull heads. I would check timing and move on unless something is noticed

 

[Scott06]

Okay thanks. Will try to get to timing it this week. Could the detonation events have caused any serious / permanent damage? Anything I should check?

Take your plugs out an look for signs of detonation. Probably unless you just hammered it while pinging it will be fine.

You can google reading spark plugs and find lots of pictures.

 

[aidanmurphy]

Pulled the plugs today and it seems that they show some signs of detonation. At least they were very very hot. I'll post some pics. I also stuck a cheap "inspection camera" into the cylinders to see what I could. Nothing jumped out at me and the camera is pretty poor quality but doesn't seem to be anything too out of order. Will post an album to the vids

Pistons

4 new items added to shared album

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[nola mike]

Not seeing any signs of detonation, though they look pretty lean

 

[aidanmurphy]

Hmm, I am assuming slightly advanced timing can't cause that lean condition. The carb is clean and the inline filter on it looked clean too, so I was thinking fuel system was fine. I did replace the fuel line from tank to pump, but it ended up being a few inches longer. Not sure if that would have any effect on the pump.

 

[nola mike]

Hmm, I am assuming slightly advanced timing can't cause that lean condition. The carb is clean and the inline filter on it looked clean too, so I was thinking fuel system was fine. I did replace the fuel line from tank to pump, but it ended up being a few inches longer. Not sure if that would have any effect on the pump.

No, you can for sure have your symptoms with overly advanced timing. Get it right and see how it runs

 

[CaptnKingfisher]

Pistons

4 new items added to shared album

photos.app.goo.gl

I'm amazed... the same guy who owns that vintage multimeter also owns a video camera to inspect the inside of his cylinders. LOL

 

[aidanmurphy]

Got my timing gun and got some time to head out and check timing. I can't figure how to put the motor in base timing mode, there are no connectors on my dizzy where you're supposed to jump the white wires. Will attach a photo. The only wire there is from the shift interrupt switch. Anyways I idled the boat and checked the timing, timing mark was right in the middle at 0. Will attach photo of my timing tab. Not sure if I can even make any adjustments without being in base timing mode, also wondering if I should just have a shop confirm my timing so I don't melt a piston.

 

[alldodge]

You need a EST timing shunt to put dizzy in full base timing mode. Google it, and they are about $10

 

[aidanmurphy]

Got the dongle in and got out to set base timing. Set at 1BTDC as per my engine serial. Still have the pinging at WOT, anything up to about 80 percent throttle is golden and I cruised at 70 percent for a while with no issues. Not that I will ride at WOT often/ever but it still irks me that it might be pinging. I recorded a clip where you can hear the chatter around the middle and the end of the video when I push to WOT. Pulled the plugs again after a few spurts at WOT and they look pretty similar to last time to me but maybe some experts here have better input. I put fresh 87 octane in with some seafoam, when I looked through the carb is was pretty clean. New fuel filter.

New video · Wednesday, Apr 20, 2022 🎬

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[aidanmurphy]

Side note: Is this too much water out of the bilge after a few hours on the water? Seems to accumulate more with riding.

New video · Wednesday, Apr 20, 2022 🎬

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