spark plug picture after 10 hours...running lean?

[94OMC]

Re: spark plug picture after 10 hours...running lean?

......Take a close look at those plugs, any "pinkish" coloring, is definitely water injestion (the beginnings of oxidation, rust!)

I took a close look at the plugs I removed from a couple weeks ago, and I don't see any pink or rust color. If it were water ingestion, would it be typical to see it on both banks of cylinders?

I'm going to pull the risers off soon - what should I be looking for?

Thanks

 

[John_S]

Re: spark plug picture after 10 hours...running lean?

"I run the correct octane (89) with a bit of sea foam,"

You are cleaning the plugs as you run the engine. Stop using the seafoam and recheck after 10-20hrs use.

Did this engine ever perform to specs?
DonS has a checklist to go through, but one of the firsts I'd do, is check to see if you are getting ignition advance at 4K. It should be close to 30 BTDC at 4K.

 

[94OMC]

Re: spark plug picture after 10 hours...running lean?

"I run the correct octane (89) with a bit of sea foam,"

You are cleaning the plugs as you run the engine. Stop using the seafoam and recheck after 10-20hrs use.

Did this engine ever perform to specs?
DonS has a checklist to go through, but one of the firsts I'd do, is check to see if you are getting ignition advance at 4K. It should be close to 30 BTDC at 4K.

I have been going through DonS checklist...just a couple more things to check like exhaust restriction and fuel restriction/air leaks. I'm also going to take the carb off for a real good cleaning for good measure.

I did check the advance when I checked timing, and it was advancing. I don't remember the exact numbers, but I checked the timing at idle (it was good), and then held the engine at 2,500 to make sure it was advancing. All seemed OK to me.

 

[94OMC]

Re: spark plug picture after 10 hours...running lean?

Pulled the risers today and they look great - no signs of water or rust in the exhaust man. So I don't think I have a water ingestion problem.

However, I am missing the port side exhaust flapper! Hopefully it is hiding down in the bottom of the exhaust and that's what's keeping my engine from hitting WOT. Now I just have to figure out how to get to the bottom of the exhaust...any pointers?

 

[2001Crownie]

Re: spark plug picture after 10 hours...running lean?

I didnt read every post but I have to dis-agree with some of them.That plug looks like your engine if running very rich,not lean...plugs should be a light tan color,those look black to me.Did anyone bring your prop into question?...I dont know about the 5.0l but my 4.3 hits the rev limiter at a little above 4800rpm...good luck.

 

[bomar76]

Re: spark plug picture after 10 hours...running lean?

That plug looks like your engine if running very rich,not lean...plugs should be a light tan color,those look black to me.

Where do you see black?????
Of all the things those plugs may indicate, rich isn't any of them.

 

[Robj]

Re: spark plug picture after 10 hours...running lean?

Where do you see black?????
Of all the things those plugs may indicate, rich isn't any of them.

Agree. Those plugs don't look rich to me. If anything they look lean, or there are the other possibilities such as water ingress.

Have a great day,

Rob.

 

[John_S]

Re: spark plug picture after 10 hours...running lean?

However, I am missing the port side exhaust flapper! Hopefully it is hiding down in the bottom of the exhaust and that's what's keeping my engine from hitting WOT. Now I just have to figure out how to get to the bottom of the exhaust...any pointers?

This may lead to your wot problem. Sorry, I can't help with an OMC drive.

Have you stopped using Seafoam to get a plug reading? The Seafoam will remove carbon and other contaminates from the cylinder. As long as you are running that, you will not get good readings.

 

[94OMC]

Re: spark plug picture after 10 hours...running lean?

This may lead to your wot problem. Sorry, I can't help with an OMC drive.

Have you stopped using Seafoam to get a plug reading? The Seafoam will remove carbon and other contaminates from the cylinder. As long as you are running that, you will not get good readings.

Thanks - yes I've stopped adding Seafoam, but there was still some in the tank when I filled up. I'll check the plugs after I've put some more hours on...

I'm going to pull the outdrive and go fishing for exhaust flapper tomorrow.

 

[mikeneal]

Re: spark plug picture after 10 hours...running lean?

I had similar questions if I was running lean a while back and looked for a possible flapper in the Y pipe, if you remove the drive you can see the bottom of the Y pipe. Also with drive removed you can run a rigid fish tape thru both side (if risers are removed 1st.

Thanks - yes I've stopped adding Seafoam, but there was still some in the tank when I filled up. I'll check the plugs after I've put some more hours on...

I'm going to pull the outdrive and go fishing for exhaust flapper tomorrow.

 

[94OMC]

Re: spark plug picture after 10 hours...running lean?

I had similar questions if I was running lean a while back and looked for a possible flapper in the Y pipe, if you remove the drive you can see the bottom of the Y pipe. Also with drive removed you can run a rigid fish tape thru both side (if risers are removed 1st.

Yeah - I pulled the drive this morning and found my flapper. It was wedged in there and blocking almost all of the exhaust. I bet she'll run a lot better now....

 

[MikDee]

Re: spark plug picture after 10 hours...running lean?

I had similar questions if I was running lean a while back and looked for a possible flapper in the Y pipe, if you remove the drive you can see the bottom of the Y pipe. Also with drive removed you can run a rigid fish tape thru both side (if risers are removed 1st.

Good Idea Mike!

 

[94OMC]

Re: spark plug picture after 10 hours...running lean?

UPDATE: took the boat for a spin, and everything is running great now that the flapper isn't blocking all the exhaust! I'll keep an eye on the plugs now that the engine is running well.