Noisy Starboard transmission...rich engine

[waybomb]

I agree, on a stock pleasure boat, on stuff like this, oem is best. Takes the guess work out of future issues.

Id be concerned with how much sludge was in that plenum.

Me, I'd start wuth a leakdown test to check the ring and valve condition.

[tomschauer]

I always (almost) subscribe to the KISS (Keep It Simple Stupid) method before buying parts etc, maybe because I am a bit simple. If the oil in the plenum is clean and has no carbon in it only misc dust, it may have been placed there by someone over zealously fogging the engine(s).

Just an idea....

[405driver]

Took all this great advice and bought a Merc OEM PCV valve.

I got my injectors back from Witchhunter. I am attaching the performance report for your casual viewing pleasure. Witchhunter has a good section on their web site about their testing and cleaning procedures and a section that offers definitions of the test results found on the attached report. I understand the results, but I don't know how much an injector has be "down" in performance before it might effect the performance of the engine. If you read the other posts, my problem has been a slightly rough idle and the engine running rich (trans rattling).

In looking at the report, my guess would be that the injectors are not the problem. It seems that a pulsed variance of 4.5% would not be enough to cause what's going on in my engine. However, as usual, I haven't a clue as to what I am talking about. Anyway, I now have clean injectors. Hopefully one "maybe" problem eliminated.

My mechanic can't help me put it back together until Tuesday, so more then on how it runs.

Concerning blow by, there is nothing coming out of the oil fill cap when removed and the compression is 165-170 on each cylinder. I know that that neither of these is "all defining" but at least there are a few good signs.

Interestingly enough, I talked with the previous owner ( I've owned the boat since last October) and he said that the trans has rattled a long as he could remember. He bought the boat new in 1998. Said his mechanic told him it was normal. Well, fuel in the exhaust and black plugs doesn't seem to be normal to me.

By the way, can anyone describe if there is a difference between the appearance of oil and gas in the exhaust?

Again, thanks for all the good input. Next week should move us along in this endeavor.

[bud37]

Thanks for the update, long process heh, I am sure you will get to the bottom of it yet, hang in there. Actually IMO if your engine was being overfueled to the extent the plugs showed it is quite possible to wash the cylinder walls a bit therefore showing oil in the exhaust as well as raw fuel.....you will have to put back together with known good stuff ( pcv and injectors) and then see the result to make a reasonable conclusion and hopefully that will be that .....

[405driver]

I like the "hopefully that will be it" part....

[hausherrs]

For what it’s worth my port trans rattles and my sbd does not. I obsessed over it for a week. Changed plugs and caps and a couple other things. Then decided to not worry about it because, well, everything works and more often than not you’ll have a rattler.

The spray pattern on those two that are "Fair" would cause the fuel to burn less than what it would if they were clean and running at their best. You might see some improvement from that but I wouldn’t hold my breath. But maybe you will be pleasantly surprised.

If I were in your shoes I would just put it back together and enjoy it for a while. I’ve had my 96 400 since summer 2016. It’s my first boat. I wait until I have about 4-5 repairs that need to be made before I start working on it. That way I don’t spend every week working on something. Today I am replacing the duck bill valves on the vacu-flush vacuum pump. I had the leaking rudder post stuffing box re-stuffed and an updated certified 450sq ft FM-200 fire suppression tank installed in the engine room. Mine was filled with recycled halon and would not pass for other reasons. I paid someone to do those things because I need proof for my insurance that they were done. I started a thread about engines not going over 2xxx rpm that turned out to be the UFO Flying Saucer filter had a bunch of junk in it.

Anyhow, good luck and keep us posted. You got a few people keeping an eye on this thread.

Thanks,

Steven

[405driver]

Thanks....where is the Flying Saucer filter, I might try that.... I have come to exactly your conclusion. If this whole thing doesn't help, I'm going to forget about it until fall.

About all we do is go out and park with my son, my grandchildren and his houseboat. I'm not driving the boat from Tennessee to the Bahamas any time soon. With that said, I'm the kind of person who wants everything to work as it should. From what I have learned so far, I don't think anything on the starboard side is about to come apart, but for some reason it doesn't sound like the port side. "Deal with it...lets go enjoy the boat"...........that's what my wife said yesterday after we sat on the back deck and watched the Masters. Doesn't get much better than that.

This coming week after we get the motor back together, I have to change the Y valve, it is leaking slightly. UGH. Then, that's about it for the summer.

Just out of curiosity, why did you change your duckbills? I wonder if mine have ever been changed.....? Takes about twenty seconds for mine to stop cycling.

I don't have a lot of hope that a new fuel pressure regulator, cleaning the injectors and a PCV valve is going to fix it, but if it doesn't, we will have eliminated a few things. If it's still running rich, I may replace the MAP sensor depending on the next computer check. We'll see.

More tomorrow night.

Thanks

[km1125]

If you get the fuel pressure corrected, I think your "rich" condition will be gone.

I wonder if the rattle might be more related to rotation. Both your engines are RH engines, correct? The reversing rotation happens in the trans or reduction drives right? So one shaft rotates the same as the engine it's attached to but the other is opposite?

[Viper]

I think you mean LH

[405driver]

Being a previous career pilot, I'm accustomed to fairly detailed manuals. I guess I should buy a set of maintenance manuals for the engines and the drives. The Carver manuals just sort of skim over the systems and say if something doesn't work, call the dealer. So, I don't really know for sure which way everything turns. As above, the guy who did the survey said that the drives turn in reverse of each other, therefore the rattle. However, I have another friend who has a 405 and neither drive rattles, his drives are very near silent and we are comparing apples to apples.
If somebody has a definitive answer as to which way everything turns in a 405 with velvet drives, it might be helpful. Probably a topic for discussion with my mechanic while we are putting the engine back together tomorrow morning.

One thing for sure, the engine is running rich and the theory is that if we can get the engine idling a little smoother, it might have a positive effect on the rattling.