Exhaust Batching

[sastanley]

Don,

I do not think the flow has decreased using the bypass valve. This, of course, is a subjective assessment. I haven't actually tested the flow with a timer or bucket, etc.., as compared to the bypass being completely open.

FYI - I have run hotter plugs in my engine in the past, but I am currently running the Champion RJ12C's, which were new last summer...they might have 25 hours on them.. & they seem to perform admirably. I'll try to get some pictures soon, as well as a more definitive assessment on the flow characteristics with the bypass open & closed.

[Mo]

Hi Guys,
I was told the NGK XR4 plugs were the cross match for the Champion hot running plugs. Don I got those from Nova Automotive in Dartmouth NS when AC Delco plugs (3 weeks old) were just terrible. That would be worth checking on though. The engine is not burning oil so that helps.

That said, Shawn described my plugs - slight sooty plugs prior to me adjusting mixture. I did spend considerable time tweaking the mixture screw on the carb. I have it set up now where the engine starts immediately with choke and slowly ease it back in...about 30 seconds after start the choke cable is all the way back in. (if the engine is warm no choke...that doesn't change) I used my nose (smell) to adjust the richness (believe it or not). I eased the screw out until I didn't have the pronounced exhaust smell...when I got there then had to make sure I had power and started fine cold...a couple of days trial and error and I think it is pretty close to where it should be. Seems to work OK. Just tinkered with it and noticed fuel consumption better also...I was running way too rich last year.

[sastanley]

Mo..do you have the adjustable main jet? I have a fixed main jet.

I am wondering where this poll is going? I wonder if it is to gather some data related to the bypass valve being set such that it allows the engine to run too cold and thus creating sooty plugs?

[Mo]

We shall see.

Hi Shawn,

I don't have an adjustable main jet...same as you. I just played with it until I got it pretty good.

I think perhaps they want to see generally how people's engines are working and what they are doing to keep them there .... or a combination there-of.

Don mentioned my plugs might be a slightly hotter running. They are supposed to be for this engine. There is also a serious danger associated with using plugs that are too hot...they can literally burn a hole in the top of the piston.

My cooling is not exactly by the book. I want to be able to lay my finger tips to the block and the head and hold them...that's just me. The only parts on the engine that are too hot to handle when running are:
- the exhaust manifold
-and a small area at the front portion of the block around where the blow-by tube comes out to the carb...pretty warm there too.
Otherwise not bad at all.

The great thing about this forum is people get enough good information to maintain the engine. They have the additional opportunity to gain an understanding of:
- it's workings
- weak areas
- troubleshooting skills,
- obtaining parts and spares
- and fixing it
...........not bad at all.

Each boat is different. Exhaust configurations on various boats; where to place additional filters...the list goes on....the knowledge is priceless to owners. Where else would they get that kind of detail from guys who own the same boat and the same engine.

So, I'll throw in my little bit and we'll see where it goes.

[sastanley]

Mo, I agree...100%. It is kind of flattering when a legend like Don Moyer asks you to do something to your motor & provide feedback...even if you don't exactly know what the master is after...just yet..

[Mo]

Something to be carefull about also.

Quote from post 30)
I have one question for you, Shawn, which relates to your reference to reducing the water flow from your exhaust by controlling the valve in your bypass loop. In a normal configuration, the bypass valve only controls the amount of water that's passing through the block and head, and unless there is a significant restriction within the block or head, the flow out the back of the boat should be approximately the same. So the question is, are you sure the flow out of the back of your boat is decreasing as you close the bypass valve?[/QUOTE]

In response to Don's above remark I can't tell a difference on mine judging by sound or looking. Attached is a picture of the valve. I have to be very careful not to forget to check the position of my valve lever after leaning in over to check the oil. Changed a condenser recently and started the boat from the cockpit to see how it ran. Heard my usual batching and had my glance over the stern...all normal.

Feeling good about correcting my ignition malfunction I went into the cabin to put everything away. I noticed my lever had pushed upward (likely by my chest) into the fully closed position. I reset it to where you see it but I didn't notice any difference in exhaust water output. So I said to myself .. "Self" ( I knew it was me because I recognized the voice!) you better not make that mistake again. I think I may remove the handle in position and save myself some trouble...that could have caused down-time on my sailing.

Hence the reason they invented a Thermostat to regulate coolant water to the head automatically. Although I don't use a T-stat I am not "anti" T-stat. I like to know that I have water to the head.

[Mo]

Mr. Moyer...Oh Great One.

Shawn,

Speaking of Don. When I bought the boat I looked at the engine and wasn't too impressed with what I saw. Fooled with it a day or two and it wouldn't stay running. I was a phone call from ordering a Beta Marine 30 hp diesel. Then I found this site, Don helped me out and the rest is history...she been a good engine.

Mr. Moyer...Oh Great One. (I'm bowing gratefully)

[roadnsky]

Nice steady flow both at idle and at cruise (1800rpm)
Pretty short run though compared to everyone else.